In DFIR, one of the worst situations is facing a cyber incident unprepared. Imagine the chaos (or don’t, as it’s a reminder of the last big incident) when you’re looking at the incident response playbook for the first time during the actual incident. We’ve all been there before. While the playbook does help, it chews into the investigation time which can be better spent gathering IOC’s and containing the cyber intrusion.
This post is aligned to Episode 2 of TLP – The Digital Forensics Podcast
A common risk that incident responders face is the reliability of forensic tools. Often, tools in the forensic lab environment may not function as anticipated when they’re run for the first time or after an update. For instance, various log types may require modifications to the log parser, or command line switches to ensure that the logs are processed (plaso has often had challenges here). Additionally, software issues, such as broken dependencies—something Linux administrators are familiar with—can disrupt the process. These problems are especially found in remote evidence acquisition, where user accounts might not work or firewalls get in the way. Even in dead box forensics, unexpected issues can arise.
Use Case: Consider a scenario where you’re conducting a full hard drive acquisition with an estimated completion time of 4, 6, 8, or even 12 hours. You decide to let the process run overnight. The next morning, you find that the acquisition has either failed, or, deceptively, it has completed but with critical issues like broken encryption or incomplete imaging. This not only wastes valuable time but also hampers the entire investigation process.
Ensuring Readiness
To avoid the disappointment and re-processing time, we must have good (and tested) evidence acquisition procedures in place. This includes having a well-built forensic lab, thoroughly tested tools, and a deep understanding of how to use these tools. Similar to preparing for an exam, you need to have commands written out and a solid grasp of how each tool functions.
Side note: If you update your tools, don’t just leave them without testing. Ensure that the update has not broken anything by running evidence through the tool that has previously been processed (using a known good command and expected output).
When an incident occurs, being well-prepared allows for quicker responses, reducing the pressure of troubleshooting under pressure. This preparation is vital when dealing with potential lateral movement by attackers, who may continue to cause damage while you’re still extracting Indicators of Compromise (IOCs) and working to contain the threat.
The forensic landscape includes a variety of tools for Windows, Linux, mobile, and OSX. However, these tools can become outdated or abandoned, posing significant challenges. Some artifact acquisition tools, particularly in memory acquisition, can sometimes cause more issues than they solve. For instance, live memory acquisition tools often modify the captured memory to some extent, which can vary between tools.
There has been research comparing tools like FTK, DumpIt, and Axiom Memory Capture has highlighted differences in the extent of memory modification. For internal incident response and digital forensics—where the case is not going to court—slight modifications in memory may be acceptable as long as the overall image is useful for analysis. No tool offers a perfect bit-by-bit copy, a limitation that we all should be aware of. In reality though, this doesn’t affect most analysis.
Looking ahead, the integration of AI in forensic tools presents exciting possibilities. AI could enhance the speed and accuracy of forensic investigations, matching the rapid pace at which adversaries use AI for malicious purposes. However, these tools will require rigorous testing before they can be fully trusted.
Envisioning a future where AI systems combat each other—malicious AI generating obfuscation methods and forensic AI counteracting these efforts—highlights the potential advancements in Security Operations Centers (SOCs) and digital forensics. The evolution of these fields will be fascinating to watch, particularly with the potential of AI to streamline forensic processes and improve incident response efficiency.
In conclusion, effective preparation, continuous tool evaluation, and staying up to date with tool updates and new methods of evidence processing will make responding to an incident easier and facilitate back-to-normal more quickly. As the cybersecurity landscape evolves, so must our strategies and tools, ensuring we remain on par with tool vendors in the DFIR space.