Richard J. Bocchinfuso

The submissions for this assignment are posts in the assignment’s discussion. Below are the discussion posts for Richard Bocchinfuso, or you can view the full discussion.

Assignment

The submissions for this assignment are posts in the assignment’s discussion. Below are the discussion posts for Richard Bocchinfuso, or you can view the full discussion.

server {
    listen 80;
    server_name site.foo.com;
    location / {
        access_log on;
        client_max_body_size 500 M;
        proxy_pass http: //INTERNAL_HOSTNAME_OR_IP;
            proxy_set_header X - Real - IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X - Forwarded - For $proxy_add_x_forwarded_for;
    }
}

server {
    listen 80;
    server_name site.bar.com;
    location / {
        access_log on;
        client_max_body_size 500 M;
        proxy_pass http: //INTERNAL_HOSTNAME_OR_IP;
            proxy_set_header X - Real - IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X - Forwarded - For $proxy_add_x_forwarded_for;
    }
}

$ dig bocchinfuso.net A +short
173.63.111.136
$ dig gotitsolutions.org A +short
173.63.111.136

$ dig google.com A google.com AAAA +short
172.217.3.46
2607:f8b0:4004:80e::200e

Assignment

The submissions for this assignment are posts in the assignment’s discussion. Below are the discussion posts for Richard Bocchinfuso, or you can view the full discussion.

from 2.3 Discussion

Jul 13, 2018 10:48pm

Richard Bocchinfuso

What is the reason behind packet loss? What can protocols do to limit packet loss? Are there tools available for providers and consumers that identify the source of packet loss?

What is the reason behind packet loss?

“A primary cause of packet loss is the finite size of the buffer involved”  (Wu & Irwin, 2017, p. 15)

Link congestion can cause packet loss. This is where one of the devices in the packet’s path has no room in the buffer to queue the packet, so the packet has to be discarded. Increasing available bandwidth can be a resolution to link congestion, this allows buffers can empty quicker to reduce or eliminate queuing.  The use of QoS to prioritize traffic like voice and video can lower the probability of a dropped packet for traffic that does not tolerate packet loss and retransmission.

Bandwidth constraints, too much data on too small of a pipe creates congestion and packet loss.

As you can see above congestion is just like this is like a four-lane road merging into one lane road. Packet loss can be an intentional thing where packets are dropped because a rule is in place to drop packets at a certain limit, hosting providers use this to control how customers use available bandwidth. Packet loss can also just occur because of unintentional congestion, where the traffic just exceeds the available bandwidth.

Device performance can also cause packet loss. This occurs in a situation where you may increase the bandwidth of the route the packet will take, but the device (router, switch, firewall, etc…) is not able to handle the load. In this case, a new device is likely required to support the network load.

For example, a Cisco ASA 5505 (Links to an external site.)Links to an external site. is meant to handle 150 Mbps of throughput, if the device is will likely begin to have issues, maybe the CPU of the device can’t process the throughput and then device experiences congestion and begins dropping packets.

Faulty hardware, software or misconfiguration. Issues can occur here from a faulty component, like an SFP (small form-factor pluggable), a cable, a bug in the device software, or a configuration issue like a duplex mismatch, can cause packet loss.

Examples of software issues which have caused packet loss: (Links to an external site.)Links to an external site.

• Cisco Bug: CSCub04965 – TCP Session hung causing Packet loss (Links to an external site.)Links to an external site.
• Cisco Bug: CSCej43682 – packet loss with CEF and GRE (Links to an external site.)Links to an external site.
• Cisco Bug: CSCtx55513 – ASA: Packet loss during phase 2 rekey (Links to an external site.)Links to an external site.

Network attacks like a Denial of Service (DoS) attack can result in packets being dropped because the attack is overwhelming a device with traffic.

What can protocols do to limit packet loss?

TCP (Transmission Control Protocol) is a connection-oriented protocol which is built to detect packet loss and to retransmit data. The protocol itself is built to handle packet loss.

UDP (User Datagram Protocol) is a connectionless protocol that will not detect packet loss and will not retransmit. We see UDP used for streaming connect like stock ticker data, video feeds, etc… UDP is often used in conjunction with multicast where data is transmitted one-to-many or many-to-many. You can probably visualize the use cases here, and how packet loss can impact the user experience. With UDP data is lost rather than the system experiencing slow or less than optimal response times.

Layer 4 Transport Optimizations

• RIP (Routing Information Protocol) and BGP (Border Gateway Protocol) make routing (pathing) decisions based on paths, policies, and rules.
• TCP Proxy and TFO (Traffic Flow Optimization)
• Compression
• DRE (Data Redundancy Elimination):  A technique used to reduce traffic by removing redundant data transmission.  This can be extremely useful for chatty protocols like CIFS (SMB).

Layer 2 and 3 Optimizations

• OSPF (Open Shortest Path First) and IS-IS (Intermediate System to Intermediate System) use link state routing (LSR) algorithms to determine the best route (path).
• EIGRP (Enhanced Interior Gateway Routing Protocol) is an advanced distance-vectoring routing protocol to automate network routing decisions.
• Network Segmentation and QoS (Quality of Service): Network congestion is a common cause of packet loss, network segmentation and QoS can ensure that the right traffic is given priority on the network while less critical traffic is dropped.

Are there tools available for providers and consumers that identify the source of packet loss?

There are no hard and fast rules for detecting packet loss on a network but there are tools and an approach that can be followed.

Some tools I use for diagnosis and troubleshooting:

• Ping (Links to an external site.)Links to an external site.: Send an ICMP (Internet Control Message Protocol) echo request packet from a source to a destination and wait for the reply.
• Traceroute (Links to an external site.)Links to an external site.: Display the route (path) and transmit time of packets from a source to a destination.
• MTR (Matt’s or My Traceroute) (Links to an external site.)Links to an external site.: an open-source utility that combines both traceroute and ping. Users can send ICMP traffic to a target and watch the path of the packets to see where packets are being dropped. This is a little tricking because ICMP traffic is often blocked by firewalls and it is also the lowest priority traffic and it’s common for an ICMP packet
• iPerf (Links to an external site.)Links to an external site.: iPerf is a tool to create and measure network bandwidth. iPerf is a client and server application that can test TCP, UDP and SCTP on but IPV4 and IPV6 networks.
• Network Sniffers: Many network sniffers work in a similar fashion, sniffers like Microsoft Network Monitor (Links to an external site.)Links to an external site. and Capsa network analyzer (Links to an external site.)Links to an external site. capture packets and allow for inspection of traffic, but undisputed leader here is Wireshark (Links to an external site.)Links to an external site. (formerly known as ethereal).
  Wireshark is a sniffer which can be used to capture traffic, isolate a TCP session and analyze the session. Once the session is isolated a filter can be applied in wireshark to view lost packets (tcp.analysis.lost_segment).
• Tcpdump and tcpreplay: tcpdump (Links to an external site.)Links to an external site. can be used to capture packets on a network, just like Wireshared and saved them to a pcap file. tcpreplay (Links to an external site.)Links to an external site. can then be used to replay this pcap. The use of tcpdump and tcpreplay is a great way to troubleshoot an issue with an application where the app is experiencing an issue and you want to troubleshoot and test in an automated fashion.
• Netcat (Links to an external site.)Links to an external site.: Allows for user controlled reading and writing to network connections using TCP or UDP. Can be a very valuable tools for troubleshooting.
• Host based application inspection: Tools like TCPView (Links to an external site.)Links to an external site.which map the host based application communication very useful.
• Etc., etc., etc.

References

Bocchinfuso, R. (2008, January 15). Fs Cisco Event V6 Rjb. Retrieved July 13, 2018, from https://www.slideshare.net/rbocchinfuso/fs-cisco-event-v6-rjb

Hurley, M. (2015, April 28). 4 Causes of Packet Loss and How to Fix Them. Retrieved July 13, 2018, from https://www.annese.com/blog/what-causes-packet-loss

Packet Loss – What is it, How to Diagnose and Fix It in your Network. (2018, May 01). Retrieved July 13, 2018, from https://www.pcwdld.com/packet-loss

Wu, Chwan-Hwa (John). Irwin, J. David. (2013). Introduction to computer networks and cybersecurity. Hoboken: CRC Press.

from 2.3 Discussion

Jul 15, 2018 1:31pm

Richard Bocchinfuso

Andrew, good post.  The only comment I would make is to be careful with using ping as the method to diagnose packet loss, great place to start if the problem is really overt, but often the issues are more complex and dropped ICMP packets can be expected behavior because they typically are prioritized out by QoS.

I typically recommend the use of paping (https://code.google.com/archive/p/paping/ (Links to an external site.)Links to an external site.) or hping3 (https://tools.kali.org/information-gathering/hping3 (Links to an external site.)Links to an external site.) to send a TCP vs ICMP request.

If you are going to use ping I would also suggest increasing the ICMP payload size, assuming the target is not rejecting ICMP requests or dropping them because of a QoS policy.

Lastly, there are lots of hops between your computer and using MTR is a great way to see where packets are being dropped, where the latency is, etc.

from 2.3 Discussion

Jul 15, 2018 8:50pm

Richard Bocchinfuso

Jonathan, couple of comments on your post.  While TCP packet loss and dropped packets have the same result, a discarded packet requiring retransmission.  Packet loss has an implied context stating that the the discarded packet was unintentional because of the reasons you mention above.  Dropped packets can also be intentional, for example ICMP (ping) traffic is often traffic deprioritized by QoS so these packets are intentionally dropped so they do not impact higher priority traffic.

UDP is a connectionless protocol so there is no ACK from the receiver.  Packets are sent and if they are lost there is no retransmit because there is no way for the protocol to know the packet was not delivered, with UDP data can be lost or delivered out of order.  There are implementations or UDP (e.g. – RUDP) where checks can be added to UDP to increase the reliability of protocol. UDP is often used in conjunction with multicast, if you think about multicast and how TCP and UDP work it becomes obvious why multicast works with a connectionless protocol like UDP and why TCP can only be used in unicast applications.

from 2.3 Discussion

Jul 15, 2018 9:35pm

Richard Bocchinfuso

For anyone looking to play with packet sniffing, regardless of the sniffer it is always good to capture a quality workload, be able to modify your lab environment and replay the workload to see what happens.  Windump (tcpdump (Links to an external site.)Links to an external site. for Windows) is great tools to capture traffic to a pcap file, but I would also become familiar with tcpreplay (Links to an external site.)Links to an external site..  You probably want to trade in that Windows box for Linux, my distro of choice for this sort of work is Parrot Security OS (Links to an external site.)Links to an external site..  There is one Windows tool I really like, called NetworkMiner (Links to an external site.)Links to an external site., check it out.  I would also get familiar with GNS3 (Links to an external site.)Links to an external site. and the NETem (Links to an external site.)Links to an external site. appliance.  So many great tools out there but GNS3 is a critical tool for learning.  Capturing a quality workload to a pcap, modifying your lab network with GNS3 and using tcpreplay to replay the workload while observing behavior provides a great way to experiment and see the impact. Looking ahead, GNS3 provides a way to apply the routing and subnetting theory that it looks like we’ll be diving into in week three.

Assignment

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The submissions for this assignment are posts in the assignment’s discussion. Below are the discussion posts for Richard Bocchinfuso, or you can view the full discussion.

Assignment

Essay Assignment

You are the CISO of a large company. Using your own machine as an example, tell me how you would harden your own machine and how you would harden machines across the company, using ideas garnered from this class.

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Final Exam

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Discussion Post

Desktop Virtualization
Discuss whether desktop virtualization is a panacea.

No, virtualization (desktop or server) is not a panacea. While complex, attackers can exploit hypervisor technology by virtualizing an operating system and running the malware at a level below the virtualized workloads, at the hypervisor layer. This approach makes the malware very hard to detect and operating system agnostic. (Ford, 2018) This type of malware has become know as a virtual-machine based rootkit (VMBR). A VMBR installs a virtual-machine monitor (VMM) underneath an existing operating system (guest os or virtual machine) and hoists the original operating system into a virtual machine. (King & Chen, 2006)

Virtualization can be very helpful for malware analysis. Virtualization can provide isolation, it can create a trusted monitor so the hypervisor can watch how the system works preventing the hypervisor from being tampered with, and it can allow for rollback or disposable computing which can be very useful for malware testing. (Ford, 2018) While countless benefits are derived from virtualization, the hypervisor is just software, and like any other software, it can have vulnerabilities. If the hypervisor were to be exploited, it could provide an attacker with low-level system access which could have serious, widespread implications. Successful exploitation of the hypervisor would give the attacker full control over everything in the hypervisor environment, all virtual machines, data, etc. (Obasuyi & Sari, 2015)

The “cloud” makes extensive use of virtualization technologies. (Ford, 2018) For example, Amazon Web Services (AWS), is built on the Xen hypervisor. Given the security concerns mentioned above and associated with the hypervisor, you can see the concern given the scale and multi-tenancy of cloud providers. (Vaughan-Nichols, 2015) Let’s face it the cloud is one giant honeypot; it’s hard to say “if” and more likey “when” will a low-level exploit happen in the cloud. Only time will tell.

To bring it back to desktop virtualization I might argue that the security concerns with desktop virtualization exceed the security concerns with server virtualization, for one reason, linked clones. The use of linked clones is quite common in desktop virtualization, but with all virtual desktops sharing common executables and libraries, malware can metastasize with each virtual desktop instantiation, and this would not require a compromised hypervisor, but rather a compromised master image. The other thing which we need to consider is transparent page sharing and the potential manipulation of EXEs and DLLs in memory at the hypervisor level and the impact it could have.

References

Ford, R. (2018, June 11). Virtualization. Retrieved June 11, 2018, from http://learningmodules.bisk.com/play.aspx?xml=L0Zsb3JpZGFUZWNoTUJBL01HVDUxNTYvQ1lCNTI4ME0xMFYxL0RhdGEvbW9kdWxlLnhtbA

King, S. T., & Chen, P. M. (2006). SubVirt: Implementing malware with virtual machines. Paper presented at the , 2006 14 pp.-327. doi:10.1109/SP.2006.38

Obasuyi, G. C., & Sari, A. (2015). Security Challenges of Virtualization Hypervisors in Virtualized Hardware Environment. International Journal of Communications, Network and System Sciences, 08(07), 260-273. doi:10.4236/ijcns.2015.87026

Vaughan-Nichols, S. J. (2015, December 04). Hypervisors: The cloud’s potential security Achilles heel. Retrieved June 13, 2018, from https://www.zdnet.com/article/hypervisors-the-clouds-potential-security-achilles-heel/

Discussion Response 1

I enjoyed your post, would like to offer up some food for thought.

There are lot’s of good reasons for Desktop Virtualization, the catalysts that I see typically revolve around centralized command and control, with the desire for centralized command and control often being aided by regulatory and/or compliance requirements. Five or so years ago we were seeing a huge push towards desktop and application virtualization on platforms like Citrix Xen Desktop, Citrix Xen AppA, and VMware View but this trend seems to have slowed, it’s not hard to understand why.

Let’s look at a few of the challenges with desktop virtualization. From a security perspective, you now have the east-west traffic to be concerned, this is the traffic taking place on the same physical hardware, not ingressing or egressing the physical hardware (north-south traffic) so network security protocols don’t really work. This was a general hypervisor problem which has been addressed, but a concern nonetheless. Next, we have the unpredictable performance profile of end-user usage, one user performing an I/O intensive process has the ability to impact all other users on that physical system. Then there is the con of centralization, the risk, a shared component outage has a much larger blast radius. All of these contributing factors make desktop virtualization fairly costly.

New technologies like SasS and browser-based apps, the rich user experience of HTML5, the ease of cross-platform development, the BYOD push, etc… seem to have slowed the desktop virtualization craze. Desktop virtualization is still happening, but it seems to have slowed. I use virtual desktops all the time for remote access or to run thick apps, but the virtual desktop is used more like an application rather than as a day-to-day shell from which I work. IMO as long as there is Java and the umpteen versions of Java, compatibility issues between apps and Java version, etc… we will have a need to use the virtual desktop to solve these issues. VDI also allows us to take think client applications and quickly centralize them, although I know many people who have done this who wish they just did an app rewrite rather than spending the time build VDI.

I agree with the VirtualizedGeek, that DaaS is a better solution than VDI for those of us need a cloud-based Windows desktop. (VirtualizedGeek, 2014) The article is a bit dated and today many of us use AWS Workspaces or another DaaS solution for this very reason. I also agree with Ben Kepes that “Desktop as a Service is last year’s solution to last decade’s problem.” (Kepes, 2014) The bottom line is the move toward mobile and web apps will continue so while VDI may not be dying I don’t expect it to flourish.

References

Kepes, B. (2013, November 06). Death To VDI. Or DaaS. Or Whatever It’s Called This Week. Retrieved June 17, 2018, from https://www.forbes.com/sites/benkepes/2013/11/06/death-to-vdi-or-daas-or-whatever-its-called-this-week/#3e4c3295096a

Rouse, M. (2018, June 17). What is east-west traffic? – Definition from WhatIs.com. Retrieved June 17, 2018, from https://searchsdn.techtarget.com/definition/east-west-traffic

VirtualizedGeek. (2014, February 18). VDI is dying so what now? Retrieved June 17, 2018, from http://www.virtualizedgeek.com/2014/02/vdi-token-ring/

Discussion Response 2

Enjoyed the post, great read as usual, always like the emotion in your writing.

I have one rule about technology, it is to never make a technology decision based on “saving money”. When the primary value proposition is “you’ll save money” it almost always tells the story that there is no other value proposition that is meaningful enough to be a motivator. I have yet to meet someone who made the decision to implement VDI for cost savings that are happy they made the decision. I have met those who had to do it for regulatory and compliance purposes who likely spent and continue to spend more on their virtual desktop infrastructure than they would have spent deploying desktops, these folks still may not be happy but they are committed to the technology to solve a business problem that they have yet to find another solution to.

Desktop virtualization has been around for a long time, Citrix the undisputed leader in the space started in 1989 with the development of their protocol called ICA (Independent Computing Architecture). In the late 1990s Citrix release MetaFrame 1.0 to match the release of Microsoft Terminal Server. Citrix capitalized on the weakness of Microsoft RDP protocol and MetaFrame and the ICA protocol became the defacto standard for multi-tenancy at scale. The mainframe and mini-computer world was used to multi-tenancy but Citrix had brought multi-tenancy to the micro-computer and Wintel platform. This market pivot actually has close parallels to the cloud pivot we are seeing in enterprise computing today. In the 90s and early 2000s consumers listened to vendors, today consumers listen to the community, the biggest voices are those consuming the platform at scale, fortunately for Citrix this wasn’t the case as they rose to market prominence. There is no doubt that today Netflix holds as much weight on a new user using AWS as AWS itself, Netflix is the 900-pound consumer gorilla and their lessons learned are consumer lessons, not the lessons of AWS who want you on the platform. The Netflix lessons are extremely relevant to the cloud, but they are also relevant to a move to multi-tenancy in any way, VDI being one example. I think we are quickly moving past the days where “a guy with a huge handlebar mustachio with a cape on the back of a wagon” can espouse a cure-all. And for those willing to buy, well, in today’s day and age it feels more like natural selection than someone being bamboozled.

Here are some of the publically available Netflix lessons with some personal commentary. I love these lessons learned and I use them in different contexts all the time. (Netflix Technology Blog, 2010) (Townsend, 2016)

1. Dorothy, you’re not in Kansas anymore. It’s going to be different, new challenges, new methods and a need to unlearn much of what you are used to doing.
2. It’s not about cost savings. Focus on agility and elasticity.
3. Co-tenancy is hard. Architecture and process matter more than ever.
4. The best way to avoid failure is to fail constantly. This is one that many enterprises are unwilling to accept. Trading the expectation of uptime for the expectation of failure and architecting to tolerate failure.
5. Learn with real scale, not toy models. Buying a marketecture is not advisable, you need to test with your workloads, at scale.
6. Commit yourself. The cost motivator is not enough, the motivator has to me more.
7. Talent. The complexity and blast radius of what you are embarking on is significant, you need the right talent to execute.

The consumption and effective use of ever-changing and complex services require us to think differently. Netflix consumes services on AWS and because they don’t have to build hardware, install operating systems, build object storage platforms, write APIs to abstract and orchestrate the infrastructure, etc… they can focus on making their application more resilient by building platforms like the Simian Army (Netflix Technology Blog, 2011) and other tools like Hystrix (Netflix Technology Blog, 2012) and Visceral (Netflix Technology Blog, 2016). The biggest problem with technologies that seemingly make things simpler is that the mass-market consumer looks for cost saving, they look for things to become easier, to lessen the hard dollar spend, to lessen the spend on talent, etc… and they don’t redirect time or dollars to the new challenges created by new technologies, this is a recipe for disaster.

References

InfoQ. (2017, February 22). Mastering Chaos – A Netflix Guide to Microservices. Retrieved June 17, 2018, from https://youtu.be/CZ3wIuvmHeM

Netflix Technology Blog. (2010, December 16). 5 Lessons We’ve Learned Using AWS – Netflix TechBlog – Medium. Retrieved June 17, 2018, from https://medium.com/netflix-techblog/5-lessons-weve-learned-using-aws-1f2a28588e4c

Netflix Technology Blog. (2011, July 19). The Netflix Simian Army – Netflix TechBlog – Medium. Retrieved June 17, 2018, from https://medium.com/netflix-techblog/the-netflix-simian-army-16e57fbab116

Netflix Technology Blog. (2012, November 26). Introducing Hystrix for Resilience Engineering – Netflix TechBlog – Medium. Retrieved June 17, 2018, from https://medium.com/netflix-techblog/introducing-hystrix-for-resilience-engineering-13531c1ab362

Netflix Technology Blog. (2016, August 03). Vizceral Open Source – Netflix TechBlog – Medium. Retrieved June 17, 2018, from https://medium.com/netflix-techblog/vizceral-open-source-acc0c32113fe

Townsend, K. (2016, February 17). 5 lessons IT learned from the Netflix cloud journey. Retrieved June 17, 2018, from https://www.techrepublic.com/article/5-lessons-it-learned-from-the-netflix-cloud-journey/

Essay Assignment

In an essay form, develop an example of an XSS vulnerability and an exploit which displays it. You will be expected to include a snippet of code which illustrates an XSS vulnerability and also provides some general discussion of XSS vulnerabilities.

[google-drive-embed url=”https://docs.google.com/document/d/1bdAAfGcwrgux3_DYSNcyIbWBvUGIDzyRMDYtLuv1u2g/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 7 – Assignment 1″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Web Vulnerabilities Module Assignment

[google-drive-embed url=”https://docs.google.com/document/d/1-mA202z2ANNYRwkeK_LE-vOWVR-ioXGF9TD9TLRRVqk/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 7 – Assignment 2″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Discussion Post

Discuss how testing of ani-malware should be conducted.

The only absolute rule seems to be, don’t conduct anti-malware testing on your production systems. Testing of anti-malware should be performed in an isolated malware testing environment, and care should be taken to ensure that the system is completely isolated. For example, if you construct a malware test lab using a hypervisor and virtual machines, but keep the virtual machines on your production network, well, let’s say that’s not isolated. If correctly set up and configured hypervisors and virtual machines can be a testers best friend.

The Anti-Malware Testing Standards Organization (AMTSO) had developed and documented all sorts of testing guidance from Principles of Testing to Facilitating Testing. The key here is that the testing method must be safe and it must use methods which are generally accepted (consistent, unbiased, transparent, empirical, etc.) (AMTSO, 2018)

The use of generally accepted tools and toolkits for malware research, testing and analysis can easily overcome certain testing obstacles, allowing the analyst to focus on the testing methodology rather than the acceptance of a specific testing tool or platform. Safely conducting testing and ensuring that you are not endangering yourself and others is the burden of the analyst; the complexity of the technologies being used to construct isolated environments and the malware itself can make this complicated, so there is plenty of room for error.

My two favorite toolkits for malware testing are:

• Flare VM (Kacherginsky, 2017) is essentially a PowerShell script that used BoxStarter and Chocolatey to turn a >= Windows 7 machine into a malware analysis distribution by quickly loading all the tools you need to do malware analysis.
• REMnux is a Linux distribution for malware analysis and reverse-engineering. Like Flare VM, REMnux contains a set of tools to perform malware analysis and reverse engineering. Because REMnux is built on Linux (an open source operating system), it can be deployed using an install script like Flare VM or via a virtual machine (VM) image which packages the OS and tools making it easy to download, deploy and use.

There are a plethora of security-focused Linux distributions like Kali Linux, Backbox Linux, and the distribution which I use, Parrot Linux. All of these Linux based security-focused distributions offer some of the tools required for malware analysis, but none are focused on malware analysis like REMnux.

Anti-malware is a requirement; it is the last line of defense. Simple malware scanners, heuristics, activity/anomaly-based detection, is not enough. Next generation anti-malware and real-time scanning and discovery is a necessity. Malware can be identified using real-time detection technologies by monitoring activities like:

• Attempts to alter restricted locations such as registry or startup files.
• Attempts to modify executables.
• Opening, deleting or editing files.
• Attempts to write to or modify the boot sector.
• Creating, accessing or adding macros to documents.

Not all anti-virus and anti-malware is created equal. avtest.org conducts independent analysis on the efficacy of anti-virus and anti-malware solutions, services like this can be an excellent resource for those looking to make the right decision when selecting anti-virus and anti-malware solutions.

I love this quote: “People have to understand that anti-virus is more like a seatbelt than an armored car: It might help you in an accident, but it might not,” Huger said. “There are some things you can do to make sure you don’t get into an accident in the first place, and those are the places to focus because things get dicey real quick when today’s malware gets past the outside defenses and onto the desktop.” (Kerbs, 2010)

References

Adams, J. (2016, June 8). Building a Vulnerability/Malware Test Lab. Retrieved June 6, 2018, from https://westoahu.hawaii.edu/cyber/building-a-vulnerability-malware-test-lab/

AMTSO. (2018, June 6). Welcome to the Anti-Malware Testing Standards Organization. Retrieved June 6, 2018, from https://www.amtso.org/

Kacherginsky, P. (2017, July 26). FLARE VM: The Windows Malware Analysis Distribution You’ve Always Needed! « FLARE VM: The Windows Malware Analysis Distribution You’ve Always Needed! Retrieved June 6, 2018, from https://www.fireeye.com/blog/threat-research/2017/07/flare-vm-the-windows-malware.html

Kerbs, B. (2010, June 25). Krebs on Security. Retrieved June 6, 2018, from https://krebsonsecurity.com/2010/06/anti-virus-is-a-poor-substitute-for-common-sense/

REMnux. (2018, June 6). REMnux: A Linux Toolkit for Reverse-Engineering and Analyzing Malware. Retrieved June 6, 2018, from https://remnux.org/

Williams, G. (2018, June 6). Detecting and Mitigating Cyber Threats and Attacks. Retrieved June 6, 2018, from https://www.coursera.org/learn/detecting-cyber-attacks/lecture/xE8ns/snort

Discussion Response 1

Good post. IMO it’s essential when discussing anti-malware to consider attack vectors. While anti-malware heuristics are getting better, aided by deep learning, the primary attack vector remains the user, and it seems unlikely that a change in trajectory is on the near-term horizon. Attackers use numerous attack vectors, and when I think about the needle used to inject the virus I think about examples such as:

• Spam: Where email or social media are the delivery mechanism for malware.
• Phishing, Spear Phishing, Spoofing, Pharming: Where attackers impersonate legitimate sources or destinations to trick unsuspecting victims to sites that capture personal information, exploit them, etc.

I use the examples above as a way to convey that exploitation often begins with the exploitation of an individual, this happens before the malware infects their system. A lack of knowledge, skill, vigilance, a sense of trust, etc. are all too often the root cause of an issue.

I just recently started taking a Coursera course called “Usable Security” and one area they focus on is HCI (Human-Computer Interaction). They stress how important it is for the designer to make the safeguards understandable and usable, not by the minority of experts but by the majority of casual users. They use two specific examples, at least so far. The first example is a medial cart with a proximity sensor. On paper, the proximity sensor seems like a great idea, but it turns out the doctors didn’t like it, so they covered the proximity sensors with styrofoam cups making the system less effective than the prior system which required the doctor to lock the computer after their session and a reasonable login timeout. The second is the SSL warning system in Firefox, the warning you get about an expired or unsigned certificate, sighting that most people don’t know what this means and add an exception without much thought.

Over the years I have observed the situations like the above with anti-malware software. The software slows the system down, do the tech user disables it or the anti-malware software reports so many false positives that the tech user disables it. The bottom line is there no replacement for human vigilance. I wonder if we can get to a place where the software can protect the user from himself or herself. Whatever the solution, I believe it will need to be frictionless, we aren’t there yet, but maybe someday.

References

Golbeck, J. (2018, June 10). Usable Security. Retrieved June 10, 2018, from https://www.coursera.org/learn/usable-security University of Maryland, College Park

Texas Tech University. (2018, June 10). Scams – Spam, Phishing, Spoofing and Pharming. Retrieved June 10, 2018, from https://www.ttu.edu/cybersecurity/lubbock/digital-life/digital-identity/scams-spam-phishing-spoofing-pharming.php

Discussion Response 2

All good points.  Seems almost inconceivable that a tester would be testing something for which they have no knowledge, but of course, we know this is often the case (and this goes way beyond anti-malware software).

You bring up a good point regarding what the tester is testing for. I think we have seen the era of “total security” products that cover everything from firewall to anti-malware, this is likely born from necessity and the need to move from reactive defensive anti-malware focused on scans to provocative strategies which attempt to keep the malware out rather than just focusing on detection and remediation after the fact. I think we are seeing systems emerge today which leverage data mining and deep learning to better protect users. With the level of sophistication being used in both malware and anti-malware I can’t imagine the role of the tester getting any easier. We live in interesting times and on a positive note, I think we can anticipate that they will only get more interesting.

Discussion Response 3

Good post. We’ve certainly seen some leaders in the security field have their ethics and motives questioned, most notably Kaspersky Lab (Volz, 2017). I have to admit in the case of Kaspersky Lab it’s hard to not wonder if this isn’t just a bunch of legislators who may have a bigger struggle with ethics and motivation than Kaspersky Lab does, this is a slippery slope. We live in a global economy and having read what Kaspersky Lab volunteered to do, I can’t wonder if this move may have some marketing flare associated with it. avtest.org has consistently rated Kaspersky Lab anti-malware among the best in the industry (AV-TEST, 2018). Is it possible that the Kremlin could have an influence on Kaspersky Lab? I suppose it is (Matlack, Riley & Robertson, 2015), but do I think this was the motivation for the legislation, not likely.

References

AV-TEST. (2018, April 06). AV-TEST – The Independent IT-Security Institute. Retrieved June 10, 2018, from https://www.av-test.org/en/award/2017/

Matlack, C., Riley, M., & Robertson, J. (2015, March 19). Cybersecurity: Kaspersky Has Close Ties to Russian Spies. Retrieved June 11, 2018, from https://www.bloomberg.com/news/articles/2015-03-19/cybersecurity-kaspersky-has-close-ties-to-russian-spies

Volz, D. (2017, December 12). Trump signs into law U.S. government ban on Kaspersky Lab software. Retrieved June 10, 2018, from https://www.reuters.com/article/us-usa-cyber-kaspersky/trump-signs-into-law-u-s-government-ban-on-kaspersky-lab-software-idUSKBN1E62V4?utm_source=applenews

Essay Assignment

How does anti-malware software detect viruses? What techniques are available, and how do they differ?

[google-drive-embed url=”https://docs.google.com/document/d/1-5Gmk97WZQ5eKVcsoXGSzJ8VJIklMxLA7U-onkgc5-I/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 6 – Assignment 1″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Viruses and Virus Detection Module Assignment

[google-drive-embed url=”https://docs.google.com/document/d/1tgs93eHUzrPxTmzt2hOQt6XA9naQ3SKi7yvEd1df8w8/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 6 – Assignment 2″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Discussion Post

Wow, week five already! The long weekend helped me get caught up and break the cycle I’ve been on, yay!

While not the latest in malware I decided to discuss WannaCry (also known as WCry or WanaCryptor). (Hunt, 2017) The reason for my choice is I have personal experience with this self-propagating (worm-like) ransomware. I have spent the last year working on various projects to mitigate the potential impact of ransom malware like WannaCry. In this post, I will explain the ransomware approach that WannaCry took, as it does not differ that dramatically from most recent ransomware. I will also talk a bit about some of the projects that I have been involved in, some of my customer’s concerns and some mitigation strategies like WORM (Write once read many, 2018) and Isolated Recovery (Korolov, 2016) that I have helped automate and implement for customers.

A simple explanation of WannaCry is that it encrypts files, rendering them useless and demands a ransom be paid in bitcoin, of course, to have the files decrypted.

Some basic information on WannaCry (Berry, Homan & Eitzman, 2017):

1. WannaCry exploits a vulnerability in Microsoft’s Server Message Block (SMB) protocol (also known as CIFS of Common Internet File System). (Microsoft, 2017) For our purposes, we can consider SMB and CIFS are synonymous, but in the interest of education the SMB protocol was invented by IBM in the mid-1980’s and CIFS is Microsoft’s implementation of SMB.
2. The WannaCry malware consists of two key functions, encryption, and propagation.
3. WannaCry leverages an exploit called EternalBlue (NVD, 2017) to exploit the vulnerability in Microsoft’s SMB protocol implementation.
4. What makes WannaCry and other ransomware attacks incredibly dangerous is that once on a corporate network they begin propagating using vulnerabilities in sharing protocols like SMB. It’s difficult to firewall these protocols because they are heavily used by users to share data across secure networks.

Ransomware attacks like WannaCry, NotPetya, and Locky created serious concern across many enterprises who store terabytes and petabytes of data on shares which are accessed using the SMB protocol. Organizations started thinking about how they could mitigate the risk of ransomware and what their recovery plan would be if they were hit with ransomware.

Many customers who share data on the Windows server platform leverage the VSS (Volume Shadow Copy Service) to take snapshots and protect / revision data. The idea of a snapshot is it is a point-in-time copy which a user can rollback to. Developers writing malicious software understand pervasive mitigation techniques like the use of VSS snapshots and they address them. Crafty developers of malicious software use vssadmin.exe to remove VSS snapshots (previous versions) so a user can’t rollback to an unencrypted version of the file(s).  (Abrams, 2016)

The obvious risk of having petabytes of data encrypted has created questions regarding the vulnerability of enterprise NAS (Network Attach Storage) devices from manufacturers like DellEMC, NetApp, etc… Enterprise-class NAS devices provide additional safeguards like filesystems which are NTFS, no hooks to vssadmin, read-only snapshots, etc… so the protections are greater, but corporations are still concerned with zero-day exploits so additional mitigation approaches are being developed. Backing up your data is an obvious risk mitigation practice, but many enterprises are backing up to disk-based backup devices which are accessible via the SMB protocol so this has raised additional questions and cause for concern. A model called “Isolate Recovery” which leverages an air gap (Korolov, 2016) and other protection methods to ensure that data is protected, this is more of a programmatic implementation of a process then it is a technology.

Example Topology
[HOST] <-> [NETWORK] <-> [SHARED STORAGE] <-> [NETWORK] <-> [BACKUP TARGET]
Note: This is a simple representation but what is important to know here is that the HOST, SHARED STORAGE and BACKUP TARGET (could be a disk-based backup target or a replicated storage device) are all SMB accessible.

Example Isolated Recovery Topology
[HOST] <-> [NETWORK] <-> [SHARED STORAGE] <-> [NETWORK] <-> [BACKUP TARGET] <-> [NETWORK] <-> /AIR GAP/ <-> [ISOLATED RECOVERY TARGET]
Note: In this case, there is a tertiary copy of the data which resides in an isolated recovery environment which is air gapped. This paradigm could also be applied with only two copies of the data by air gapping the backup target, little tricker, but it can be done.

From a programmatic process perspective, the process might look something like this: https://gist.github.com/rbocchinfuso/a8b688546fad294d04281ab6eb632bfd#file-isolatedrecovery-md

A WORM (write once read many, not work as in virus) process is triggered via cron or some other scheduler or trigger mechanism might look something like this: https://gist.github.com/rbocchinfuso/b78a8a3a41021fc0df9c/#file-retentionlock-sh
Note:  This script is specific to WORM on a Data Domain disk bases backup device and leverages a feature called Retention Lock. The atime (access time) (Reys, 2008) of the file(s) is changed to a date in the future which places the file in WORM compliant mode until such date, once the date is reached the file reverts back to RW and can be deleted or modified.

References

Abrams, L. (2016, April 04). Why Everyone Should disable VSSAdmin.exe Now! Retrieved May 29, 2018, from https://www.bleepingcomputer.com/news/security/why-everyone-should-disable-vssadmin-exe-now/

Air gap (networking). (2018, May 27). Retrieved May 29, 2018, from https://en.wikipedia.org/wiki/Air_gap_(networking)

Berry, A., Homan, J., & Eitzman, R. (2017, May 23). WannaCry Malware Profile. Retrieved May 29, 2018, from https://www.fireeye.com/blog/threat-research/2017/05/wannacry-malware-profile.html

Hunt, T. (2017, May 18). Everything you need to know about the WannaCry / Wcry / WannaCrypt ransomware. Retrieved May 29, 2018, from https://www.troyhunt.com/everything-you-need-to-know-about-the-wannacrypt-ransomware/

Korolov, M. (2016, May 31). Will your backups protect you against ransomware? Retrieved May 29, 2018, from https://www.csoonline.com/article/3075385/backup-recovery/will-your-backups-protect-you-against-ransomware.html

Reys, G. (2008, April 11). atime, ctime and mtime in Unix filesystems. Retrieved May 29, 2018, from https://www.unixtutorial.org/2008/04/atime-ctime-mtime-in-unix-filesystems/

Microsoft. (2017, October 11). Microsoft Security Bulletin MS17-010 – Critical. Retrieved May 29, 2018, from https://docs.microsoft.com/en-us/security-updates/securitybulletins/2017/ms17-010

NVD. (2017, March 16). NVD – CVE-2017-0144 – NIST. Retrieved May 29, 2018, from https://www.bing.com/cr?IG=F94DFB39323448E6A46972AE19E1BB95&CID=304F78623FEB653F3DCF739C3E166483&rd=1&h=Dh-3S1QaiFT9tJkWNYeBAluFO8Y9ylpehdjBtEs6kAU&v=1&r=https://nvd.nist.gov/vuln/detail/CVE-2017-0144&p=DevEx.LB.1,5527.1

Write once read many. (2018, April 10). Retrieved May 29, 2018, from https://en.wikipedia.org/wiki/Write_once_read_many

Discussion Response 1

Good post on a very relevant and current topic.   IMO this trend will continue, the replacement of ASICs and RTOS with commodity ARM/x86 architecture and Linux makes it a lot easier for someone to create malicious code that can exploit routers across multiple manufacturers like Linksys, MikroTik, Netgear, and TP-Link.  I remember 20 years ago when if you wanted to go fast you used an ASIC and an RTOS like VxWorks, but x86 got so fast that ASICs no longer made sense for most applications, the ability to commoditize the hardware with a general purpose OS like Linux drove down cost and increased release velocity, a win all around.  With that said I think we may be on the doorstep fo a new cycle, we are seeing general purpose GPUs being used for everything from machine learning to crypto mining, these are essentially general purpose integrated circuits.  Power and environmental requirements are a big deal with general purpose GPUs and I believe we are on the doorstep of a cycle that sees the return of the ASIC. The TPU is is the beginning of what I believe will be a movement to go faster, get greener and more secure.

Discussion Response 2

Well done, as usual, well researched written and engaging exploration of different types of malware.
Response short this week because I spent most of my reading and responding time on Dr. Ford’s polymorphic coding challenge, a great exercise, wish there was more work like this.

Discussion Response 3

Dr. Ford’s polymorphic coding challenge

Anyone else given Dr. Ford’s polymorphic coding challenge a try?

Here is where I am:

1. I am a Linux user so fired up a Win7 VM (suppose I could have done this in a dosbox or qemu freedos session, like Dr. Ford suggested, but been so long since I worked in 80 columns I find it unbearable).
2. Used Bloodshed Dev-C++ w/ MinGW as C compiler.
3. Got this far but I think I am missing something because obviously, the hex signature is the same for each .com file. Feel like this should not be the expected behavior.

Source Code: https://gist.github.com/5859ee8be77fd188f78b64eaa8538c62#file-hello-c

YouTube video of the compile, execute and hex signature view of hello0.com and hello1.com files: https://youtu.be/2vQOS4E1JB0
Note: Be sure to watch in 1080p HD quality.

I am not sure how I would alter the hex. I believe the hex code at the top of the stack needs to be what it is, the hex code for “Hello World!” just maps back to the hex for the ASCII characters.

When I look at hello0.com, hello1.com, etc… with a hex viewer the hex is the same, as you would expect. Does anyone have any thoughts on this? I would think a virus scanner would pick up this signature pretty easily.

Discussion Response 4

Replying to my own post with disassembled hello0.com and hello1.com files.
Wondering if this is polymorphic because hello.exe and the spawned hello?.com files have differing signatures.

> ndisasm hello0.com
00000000 0E push cs
00000001 1F pop ds
00000002 BA0E01 mov dx,0x10e
00000005 B409 mov ah,0x9
00000007 CD21 int 0x21
00000009 B8014C mov ax,0x4c01
0000000C CD21 int 0x21
0000000E 48 dec ax
0000000F 656C gs insb
00000011 6C insb
00000012 6F outsw
00000013 20576F and [bx+0x6f],dl
00000016 726C jc 0x84
00000018 642124 and [fs:si],sp

bocchrj@WIN7 C:\src\hello
> decompile –default-to ms-dos-com hello0.com

bocchrj@WIN7 C:\src\hello
> decompile –default-to ms-dos-com hello1.com

bocchrj@WIN7 C:\src\hello
> type hello0.asm
;;; Segment code (0C00:0100)

;; fn0C00_0100: 0C00:0100
fn0C00_0100 proc
push cs
pop ds
mov dx,010E
mov ah,09
int 21
mov ax,4C01
int 21
0C00:010E 48 65 He
0C00:0110 6C 6C 6F 20 57 6F 72 6C 64 21 24 llo World!$

bocchrj@WIN7 C:\src\hello
> type hello1.asm
;;; Segment code (0C00:0100)

;; fn0C00_0100: 0C00:0100
fn0C00_0100 proc
push cs
pop ds
mov dx,010E
mov ah,09
int 21
mov ax,4C01
int 21
0C00:010E 48 65 He
0C00:0110 6C 6C 6F 20 57 6F 72 6C 64 21 24 llo World!$

Essay Assignment

What are the financial and other models which drive malware? How do they impact the types of malware seen?

[google-drive-embed url=”https://docs.google.com/document/d/1F9ET0EbuasT_E0f_1TOUqOzaCkrciUfGozEcbCC2JfE/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 5 – Assignment 1″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Malware History Module Assignment

[google-drive-embed url=”https://docs.google.com/document/d/13zIZqwoLdvYj72Hx6F3itdMnmQm3OKI6OjxohvzCJ_8/preview?usp=drivesdk” title=”Bocchinfuso – FIT – MGT5156 – Week 5 – Assignment 2″ icon=”https://drive-thirdparty.googleusercontent.com/16/type/application/vnd.google-apps.document” width=”100%” height=”400″ style=”embed”]

Discussion Post

Discuss ROP and code injection.

Late yet again, probably later than I needed to be, but like Dr. Ford said this week at the beginning of the lecture, this was the week I was waiting for, and I had to get a little dirty and break some stuff.

Code injection typically refers to getting something (data) that is not machine code to run as code. Code injection tries to take control of a machine by gaining privilege, the privilege that code injection works to obtain is the ability to run binary code.

To understand code injection and buffer overflows understanding the stack is essential. Return-Oriented Programming (ROP) focuses on overwriting a buffer on the stack, which overwrites the return address and allowing the attacker to jump back onto the stack and execute an instruction, to prevent this, a few defense mechanisms have been developed. (Ford, 2018)

• The no-execute flag marks something in makes memory non-executable. Data Execution Prevention (DEP) works by using the no-execute flag to prevent attackers from executing data as if it were code. Attackers are unable to execute code from the stack.
• Address Space Layout Randomization (ASLR) works by randomly moving segments of a program around memory; this prevents the attacker from predicting gadget addresses.
• Stack cookies (canaries) is a random value written to the stack immediately preceding the return address. Before the return address is executed the system checks to see if the canary has been overwritten, it the canary has been overwritten the system will trap execution.

ROP is based on the Return-to-Libc exploit technique but uses gadgets from different areas of memory to create an executable program.

ROP gadgets may look like:
0x1000b516 : pop eax ; pop ebp ; ret
0x10015875 : pop eax ; pop ebp ; ret 0x1c
0x1000ffe3 : pop eax ; pop ecx ; xchg dword ptr [esp], eax ; jmp eax
(apriorit, 2017)

While the widespread adoption of DEP which ensures that all writable pages in memory are non-executable has made classic code injection attacks difficult, ROP has become the approach for all modern attacks. Rather than injecting malicious code the attacker chains together existing code which already exists in the stack, these code snippets which are taken from the stack and are called gadgets. (TehAurum, 2015)

I was really interested in getting some hands-on experience here to see how this worked in the real world. A bit of googling and I happened across this website: https://samsclass.info/127/proj/lbuf1.htm – I fired up a Linux machine with Vagrant on my desktop and started playing.

Here is my ASLR example
Note:  I ran in debug mode to show all the commands.  Lines prefixed by the + symbol are input commands and lines with no prefix are output.
vagrant@vagrant-ubuntu-trusty-64:~$ sh -x aslr.sh
+ echo Let’s make sure ASLR is enabled
Let’s make sure ASLR is enabled
+ sudo tee /proc/sys/kernel/randomize_va_space
+ sudo echo 1
1
+ echo Let’s look at the C code that will print the esp (pointer) memory address
Let’s look at the C code that will print the esp (pointer) memory address
+ cat esp.c
#include <stdio.h>
void main() {
register int i asm(“esp”);
printf(“$esp = %#010x\n”, i);
}
+ echo Let’s compile the source code into an executable program
Let’s compile the source code into an executable program
+ gcc -o esp esp.c
+ echo Let’s execute the the binary executable esp three times
Let’s execute the the binary executable esp three times
+ ./esp
$esp = 0xd47931b0
+ ./esp
$esp = 0x5526d700
+ ./esp
$esp = 0xf7542b00
+ echo You can see that the memory address changes each time (ASLR at work here)
You can see that the memory address changes each time (ASLR at work here)
+ echo Let’s disable ASLR
Let’s disable ASLR
+ sudo tee /proc/sys/kernel/randomize_va_space
+ sudo echo 0
0
+ echo Lets’ execute the binary executable esp three more times
Lets’ execute the binary executable esp three more times
+ ./esp
$esp = 0xffffe620
+ ./esp
$esp = 0xffffe620
+ ./esp
$esp = 0xffffe620
+ echo You can see that now the memory ddress remaind the same each tiem (ASLR disabled)
You can see that now the memory ddress remaind the same each tiem (ASLR disabled)
vagrant@vagrant-ubuntu-trusty-64:~$

I pushed on to more more complex exercises; these are both excellent ones:

• Exploiting “Vulnerable Server” for Windows 7
• Defeating DEP with ROP

A couple of pointers to get started:

1. Get Virtualbox to build your sandbox. (https://www.virtualbox.org/wiki/Downloads)
2. Download a Windows 7 Vbox image (https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/) to run the vulnserver executable you will get above on (note: get vulnserver.zip from the alternate link)
3. Download Kali Linux for Vbox image (https://www.offensive-security.com/kali-linux-vm-vmware-virtualbox-hyperv-image-download/)

I left a bunch of stuff out like how to configure networking, getting going with Immunity Debugger, etc… but it’s about the journey, not the destination. Right?

References

Carlini, N., & Wagner, D. (2014, August). ROP is Still Dangerous: Breaking Modern Defenses. In USENIX Security Symposium (pp. 385-399).

Ford, R. (2018, May 23). Vulnerabilities: How Things Go Wrong, Part 2. Retrieved May 23, 2018, from http://learningmodules.bisk.com/play.aspx?xml=L0Zsb3JpZGFUZWNoTUJBL01HVDUxNTYvQ1lCNTI4ME04VjEvRGF0YS9tb2R1bGUueG1s

Shacham, H. (2007, October). The geometry of innocent flesh on the bone: Return-into-libc without function calls (on the x86). In Proceedings of the 14th ACM conference on Computer and communications security (pp. 552-561). ACM.

TehAurum. (2015, December 30). Exploit Development: Stack Buffer Overflow – Bypass NX/DEP. Retrieved May 25, 2018, from https://tehaurum.wordpress.com/2015/06/24/exploit-development-stack-buffer-overflow-bypass-nxdep/

apriorit. (2017, June 02). ROP Chain. How to Defend from ROP Attacks (Basic Example). Retrieved May 25, 2018, from https://www.apriorit.com/dev-blog/434-rop-exploit-protection

Discussion Response 1

Good post, given that you were interested in tips I thought I would respond with a toolkit for playing with buffer overflows and code injection.
The toolkit (assuming you are a Windows user):

• Code:Blocks:  http://www.codeblocks.org/downloads/binaries
  • This is a good free C IDE and Compiler
  • Note:  Grab either codeblocks-17.12mingw-setup.exe or codeblocks-17.12mingw-nosetup.zip
  • Note:  To use the debugger you will need to set it up Setting -> Debugger -> Default, and enter path to gdb32 (on my system this is  path_to\codeblocks-17.12mingw-nosetup\MinGW\gdb32\bin\gdb32.exe but it will vary, just find gdb32.exe and enter full path here).  You will also need to make sure you create a project and add .c files to the project otherwise you won’t be able to debug.
• OllyDbg:  http://www.ollydbg.de/ or IDA https://www.hex-rays.com/products/ida/support/download.shtml
  • Both good debuggers and disassemblers that will let you view the stack.

Some code to get started with:
/* vuln.c */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int func (char *str)
{
char buffer[5];
strcpy(buffer, str);
return 1;
}
int main(int argc, char **argv)
{
char str[517];
FILE *inputfile;
inputfile = fopen(“inputfile.txt”, “r”);
fread(str, sizeof(char), 517, inputfile);
func (str);
printf(“Returned Properly\n”);
return 1;
}

– Create a text file called inputifile.txt and place at least 517 characters in it.
– Compile and execute vuln.c
– Set a breakpoint at main() and debug to see what happens.

Play around with the size of the read or write buffer:
By Changing the value of 5 in “char buffer[5]” in func() to 517
OR
By changing the value of 517 “char str[5]” and “fread(str, sizeof(char), 5, inputfile)” in main() to 5

If you debug while you play you will start to see things happen.

Happy hacking!

Discussion Response 2

I’ve started doing some additional research and sandboxing because I am wondering about Return Oriented Programming (ROP) as a method to circumvent Address Space Layout Randomization (ASLR).  Need some hands-on time to really understand how gadgets can be chained given that the address space is randomized.

Doing some additional reading and experimenting to better understand the topic:

• Exploit writing tutorial part 10: Chaining DEP with ROP – the Rubik’s[TM] Cube
• Universal DEP/ASLR bypass with msvcr71.dll and mona.py
• Lec07: Return-oriented Programming
• Also playing with Ropper and Ropa to discover and build gadget chains.

Anyway, I feel like I have a good handle on buffer overflows and ROP when ALSR is disabled.  I have played with this on Linux by disabling ASLR on Linux (sudo echo 1 | sudo tee /proc/sys/kernel/randomize_va_space) and when debugging I can see that instructions always reside in the same stack address.  OK, back to the sandbox.

Discussion Response 3

Sharing this link
All here is a good free sample from a Coursera and the University of Maryland that reviews much of what we spoke about this week. I found it helpful to reinforce the concepts so I am sharing with you.

https://www.coursera.org/learn/software-security/lecture/Lz5GW/low-level-security-introduction

Essay Assignment

Describe in detail code injection attacks and the countermeasures that exist to stop them. What future solutions are there?

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Midterm Exam

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Grade: 98%