RegRipper

If someone is new to including the Windows Registry as part of their analysis process, and doesn’t understand the purpose of the transaction logs, nor how they work, they’d likely look at this table and think, “Well, I’m not using RegRipper! Handling the transaction logs are important to Chris Ray, and while I don’t know why, I’m going to go along with what Chris recommends!”

The statement, “Does not handle transaction logs” doesn’t tell the whole story, as I purposely wrote RegRipper to not handle the transaction logs. From my perspective, incorporating transaction logs into your analysis needs to be a purposeful, intentional decision. Incorporating transaction logs certainly has it’s place in any analysis process for Windows systems, but it should not happen automagically, without the analyst/examiners knowledge. And it should not  just happen every time. Further, why should I write out code for processing transaction logs, when as it is, there are a number of other tools that already allow you to do so? Why re-write this capability? 

You know, this kind of thing has happened before. In 2012, at a pretty big DF/IR security conference, a Google engineer was presenting on an enterprise-wide response capability, and included a slide that said, “RegRipper does not scale to the enterprise.” I was in the front row, because…you know…DF/IR, and was a little taken aback by this statement. This was like stating that the F-150 truck, the most popular model of light pickup, does not transition to airplane mode. No, because it was never intended to, and it wasn’t designed that way. So, rather than reaching out and engaging the author of the tool, and asking, “hey, what do you think about making this an enterprise tool?”, the presenter simply made their statement, and left it at that.

Now, why did I want handling the transaction logs to be a purposeful, intentional decision? If you’ve ever processed the transaction logs, you’ll notice that when you apply the transaction logs to a Registry hive, the hive file itself remains the same size; keys and values are updated or added, but the file itself remains the same size, even through the hash changes. This means that for the resulting hive file, unallocated space within the hive file is overwritten…deleted keys and values, and possibly even slack space, are overwritten.

Why does this matter? Well, consider the recent write-up on the DEVMAN ransomware variant (from ANY.RUN). The image to the left discusses file lock evasion (the inclusion of “persistence” in the heading is a bit misleading), and states, “Each of these entries is quickly deleted after being written…”, which means these entries become part of unallocated space. Now, this may not be important to you, based on your investigative goals…or it may be very important.

So, to be clear, if you’re at all interested in data deleted from the Registry, and you understand that Registry hive files themselves contain unallocated space, and that values can contain slack space, you might not want to just automatically apply transaction logs. Depending upon the timing of the incident and your investigative goals, you may want to first fully parse the hive file, before applying the transaction logs and applying the same parsing process a second time. Sort of a “before” and “after” snapshot of the hive.

Neither RegRipper v3.0 nor RegRipper v4.0 processes the transaction logs; however, both are open source, and you can write your own plugins, or modify current plugins in any way you choose, such as changing the output format. For example, both versions include multiple plugins that output in 5-field TLN format (for inclusion directly into a timeline events file), and v4.0 has several plugins that output in JSON format. I get it, though…the TLN output is meaningless if you’re not creating timelines.

Also, with RegRipper v4.0, I got Yara working within RegRipper, meaning that you can run Yara rules against Registry values, right from RegRipper.

Finally, both versions include plugins to do various parsing, such as parsing unallocated space, parsing Registry value sizes, locating EXE/PE files in Registry values, etc.