Welcome!

Related Topics: Cloud Security

Cloud Security: Blog Post

Malware Analysis - A Cost Effective and Quick "How To"

Full time malware analysis is expensive, this method provides a fast and simplified approach that produces results.

Malware analysis can be a time consuming process, especially when dealing with a sample from skilled attackers with time and money on their side . There is no doubt that fully reversing malware and finding out how it works is the most effective way to learn how to defend against it, but most businesses don't have the time or the professional resources to do it.

There are ways in which you, a Computer Network Defender, can glean enough information from malware to be used in IDS and AV signature creation, DNS poisoning and blocking as well as sharing with the CND community. This can be accomplished in a cost effective manner (maybe even free) and in an efficient manner that can rival very long code based analysis.  There are even cases where in depth knowledge of how to fully reverse the sample is not needed.

It should be noted that this is a low tech, high level mechanism for capturing indicators from malware. It should not be considered a substitute for fully analyzing malicious software, as sophisticated samples can defeat a lab environment similar to this quite easily. I will not be covering anything related to debugging the malware, that is outside of the intention of this "How-to".

Requirements
Before we start, you will need to procure a few bits and pieces:

  • Host machine with enough storage and memory to run at least 2 virtual machines concurrently, 4GB of ram and at least 30GB would be the minimum requirement.
  • A virtualization platform, there are several on the market, some of them are free to use, VirtualBox and Xen to name a couple. I will be using VMWare Fusion for this demonstration.
  • A copy of "REMNUX", a reverse-engineering malware linux distribution available at http://zeltser.com/remnux/.
  • A licensed copy of MS Windows (this will be your victim host). I will be using WindowsXP for this demonstration.
  • Free and open source tools for analysis of the Windows host (Putty, RegShot, Sysinternals, etc etc)

Setting Up the Victim Host Machine
Something to consider when setting up your victim host machine is system and software patches. Depending on what you are testing on your victim host, it may only affect a certain version of Windows, or possibly only to a certain patch level. Something I like to do is to "snapshot" my "victim" host machines through various patch stages, that way if I need to roll back, it's as easy as choosing a snapshot and "rolling back". This also applies to the types of software you install on your victim, snapshot your host with different versions of java, flash and adobe reader to be able to quickly select a vulnerable configuration. Consider outfitting your malware analysis lab setup with hosts that mimic your native operating environment. If you only utilize Windows 7 and do not allow Firefox on your network, then set up your victim machines to match that configuration.

A screenshot of the VMWare Fusion "Snapshot" process

Once you have finished patching your host, downloading and installing various types of software to aid in allowing successful exploitation you are going to setup a new network adapter, and set it for "host-only". This will keep your host from accidentally reaching the Internet once infected. It will also allow you to send the traffic to another machine to analyze what your victim is trying to do once successful exploitation has taken place.

  • Set the IP on your victim host to a non-routable address, for instance 10.1.1.10.
  • Set your router or gateway to be 10.1.1.1, this will the IP address of your REMNUX virtual machine.

Setting Up the REMNUX Host Machine
One of the main purposes for the REMNUX virtual machine in this demonstration is simply to act as a catch-all for network traffic originating from your now exploited victim host. REMNUX has many uses and capabilities both for the beginner and advanced malware reverse engineer, but we want fast indicators from our malware sample so that we can start defending against it immediately.

The REMNUX virtual machine is ready to go once imported into your virtualization platform with minimal modifications.  We are simply going to add a network adapter in "host-only" mode and set the IP address to a non-routable IP. REMNUX will act as the internet "gateway" and DNS server for our victim machine. This will allow us to see all network requests and DNS requests that come from our infected victim host.

A screenshot of the "REMNUX" desktop
A screenshot of the "REMNUX" network interfaces config, modify to suite your needs.

Infecting the Host
Now that you have the infrastructure in place, test your connectivity between the victim virtual machine and the gateway virtual machine. Have Wireshark running on the gateway box to verify successful connectivity. Attempt to SSH from your victim host to the gateway using putty. You can use "pscp.exe" within the Putty suite to move the original malware, and any malicious files the malware creates or drops onto your victim. Once you have moved the file over to your REMNUX host, you can take the MD5 of the original malware, before it is run. This will help in creating virus signatures and give you the required information for sharing within the CND community.

The victim host pre-infection with Process Explorer running.

Utilizing "Regshot", take a snapshot of the "C:" drive pre infection, that way you will have something to compare after your host is infected. Regshot will record the current windows registry, all windows directories and files before infection, allow you to record again after infection, and then compare the changes made to the host.

The victim host running Regshot and Process Explorer

You can now move your malware sample to the victim host. Ensure that you are running the necessary services and tools on your REMNUX host to capture the traffic. If you are not looking to interact with the malware, Wireshark can provide a wealth of data with not much in-depth knowledge. If you are looking to interact however, please consult the REMNUX readme for more information on "honeyd", "farpd" and "fakedns".

I also recommend running some kind of process explorer on the victim host to monitor what the malware does, any new processes it may spawn or kill. Sysinternals suite has several great tools, Process Explorer and Process Monitor are my two favorites.

Capturing the Indicators
Once executed on your victim host, you can record the information being fed to ProcMon, allowing you to watch what the malware does. You may see new applications start, processes get killed and new processes start. These are all indicators of the malware, and essential data to capture.

The victim host has a new process running attached to an executable with PID 2168

Watch your REMNUX host, check to see if any callouts are being made by the malware and see if it attempts to resolve DNS addresses. Often times once the DNS has successfully resolved, you will witness the malware attempt to connect to the Command & Control domain over an HTTP/HTTPS port.

A screenshot of Wireshark capturing the first DNS resolution attempt by the malware.
A screenshot of Wireshark capturing the second DNS resolution attempt by the malware.

A Note on DNS Resolution with Malware
The malware may attempt to resolve a known good website, this can be for internet connectivity checking as well as an attempt to fool someone monitoring it. If the malware is unable to resolve lets say “google.com” it may simply die on the victim host, and never try to reach the real command and control domain (CnC). This is when you want to have “fakedns” running on your REMNUX host, it will resolve any domain asked, this will then give the malware the positive connectivity test it is looking for, at which point may try to resolve the actual CnC domain.

Once you are satisfied with the length of time you have let the malware run, 10 minutes or less usually suffices, you can take the second “Regshot’ of the system. This will capture any changes made to the system by the malware. Once it has completed the second pass, compare the two and analyze the output. “Regshot” will reveal any new files created, deleted or modified. It will show you if any new registry keys were added or changed and any services that were created. It is an essential tool in the analysis toolbox.

A screenshot of the "Regshot" compare results.

As you can see with the "dir /ah" command, the files that were hidden on the victim. These files were all dropped from the malicious word document.

A screenshot showing the hidden files added to the temp directory on the victim host.

Once you have located the dropped or newly added malware on the victim host, you should move them over to your "REMNUX" host for analysis. These files are also indicators of a positive infection and should be included in your analysis of the initial malware. The MD5 hashes of these files are just as relevant for blocking and signature development as the principle delivery of these files, e.g. malicious word document, can easily change in future attempts.

Share Your Findings - One of the Most Important Pieces to Computer Network Defense
From this quick, and high level analysis of the malicious word document you were presented with several indicators that can benefit other Computer Network Defenders. One thing that I  have learned is that not everyone catches or sees something the way I may I see it.  So when I look at a piece of malware, no matter how simple I think it may be, I share it with the hopes that the indicators could assist others.

It is essential that you share as much information as you are comfortable with, as it may help to thwart future attempts against other targets. Collaboration amongst teams can help to stop these types of infections and identify current infections if they exist within your network. If possible, share any Command & Control Domains, MD5 Hashes, IP addresses, File Names and Sizes and anything else you feel is relevant to the infection.

More Stories By Cory Marchand

Cory Marchand is a trusted subject matter expert on topics of Cyber Security Threats, Network and Host based Assessment and Computer Forensics. Mr. Marchand has supported several customers over his 10+ years within the field of Computer Security including State, Federal and Military Government as well as the Private sector. Mr. Marchand holds several industry related certificates including CISSP, EnCE, GSEC, GCIA, GCIH, GREM, GSNA and CEH.

Latest Stories
@DevOpsSummit at Cloud taking place June 6-8, 2017, at Javits Center, New York City, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long developm...
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this ca...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
DevOps and microservices are permeating software engineering teams broadly, whether these teams are in pure software shops but happen to run a business, such Uber and Airbnb, or in companies that rely heavily on software to run more traditional business, such as financial firms or high-end manufacturers. Microservices and DevOps have created software development and therefore business speed and agility benefits, but they have also created problems; specifically, they have created software securi...
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business. Though, IoT is far more complex than most firms expected with a majority of IoT projects having failed. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, Chief IoTologist at Wipro, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology portfolios and business models to adopt and leverage IoT. He will delve in...
In the enterprise today, connected IoT devices are everywhere – both inside and outside corporate environments. The need to identify, manage, control and secure a quickly growing web of connections and outside devices is making the already challenging task of security even more important, and onerous. In his session at @ThingsExpo, Rich Boyer, CISO and Chief Architect for Security at NTT i3, will discuss new ways of thinking and the approaches needed to address the emerging challenges of securit...
One of the hottest areas in cloud right now is DRaaS and related offerings. In his session at 16th Cloud Expo, Dale Levesque, Disaster Recovery Product Manager with Windstream's Cloud and Data Center Marketing team, will discuss the benefits of the cloud model, which far outweigh the traditional approach, and how enterprises need to ensure that their needs are properly being met.
As cloud adoption continues to transform business, today's global enterprises are challenged with managing a growing amount of information living outside of the data center. The rapid adoption of IoT and increasingly mobile workforce are exacerbating the problem. Ensuring secure data sharing and efficient backup poses capacity and bandwidth considerations as well as policy and regulatory compliance issues.
In his session at 20th Cloud Expo, Chris Carter, CEO of Approyo, will discuss the basic set up and solution for an SAP solution in the cloud and what it means to the viability of your company. Chris Carter is CEO of Approyo. He works with business around the globe, to assist them in their journey to the usage of Big Data in the forms of Hadoop (Cloudera and Hortonwork's) and SAP HANA. At Approyo, we support firms who are looking for knowledge to grow through current business process, where even...
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions with...
Cloud Expo, Inc. has announced today that Andi Mann and Aruna Ravichandran have been named Co-Chairs of @DevOpsSummit at Cloud Expo 2017. The @DevOpsSummit at Cloud Expo New York will take place on June 6-8, 2017, at the Javits Center in New York City, New York, and @DevOpsSummit at Cloud Expo Silicon Valley will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
@DevOpsSummit has been named the ‘Top DevOps Influencer' by iTrend. iTrend processes millions of conversations, tweets, interactions, news articles, press releases, blog posts - and extract meaning form them and analyzes mobile and desktop software platforms used to communicate, various metadata (such as geo location), and automation tools. In overall placement, @DevOpsSummit ranked as the number one ‘DevOps Influencer' followed by @CloudExpo at third, and @MicroservicesE at 24th.
What are the new priorities for the connected business? First: businesses need to think differently about the types of connections they will need to make – these span well beyond the traditional app to app into more modern forms of integration including SaaS integrations, mobile integrations, APIs, device integration and Big Data integration. It’s important these are unified together vs. doing them all piecemeal. Second, these types of connections need to be simple to design, adapt and configure...