Thursday, April 24, 2008

RegRipper Video Posted

Hogfly emailed me last night to let me know that he'd posted a video on how to use F-Response and RegRipper together in live response. There's no audio to the video, but it's cool nonetheless...Hogfly does a great job of putting in cues, and focusing in so that the viewer can see what's going on up-close.

One thing that I wanted to address, though, is something that Hogfly stated in his blogpost:

Harlan has said this tool is not designed for live response...

For the record, I never said that. What I did say is:

RegRipper is NOT intended to be run on live Registry hive files.

There's a difference. RegRipper was NOT intended to be run against C:\Documents and Settings\hcarvey\NTUSER.DAT while I'm logged into my system...the hive file is live and locked by the system (populating the HKEY_CURRENT_USER hive in RegEdit). However, what Hogfly did was completely different...he used the excellent tool F-Response to access the remote drives as read-only physical disks, and then used FTK Imager to extract the hive files. You can do this on your own system as up FTK Imager, add your physical disk as an evidence item, and extract your hive files into another location in the file system. At that point, when you fire up RegRipper, you're not longer really doing "live response".

Thanks, Hogfly...great video! And a mighty THANKS goes out to Matt Shannon for coming up with F-Response...for recognizing and filling a very important need. With what's coming down the road with F-Response, as well as with other tools, the face of incident response and computer forensic analysis is now changing, in a very positive direction!

Sunday, April 20, 2008

Updated RegRipper

I posted an updated version of RegRipper (2.01A, Basic Edition) up on had a couple of small updates to the GUI, mostly in the area of input validation (thanks to sippy for the input on that), but nothing to warrant a new version number, really. A quick run-down of updates includes:

- GUI input validation stuff (thanks to sippy)

- Added '-c' switch to rip.exe, so that when you list the plugins (ie, 'rip -l') you can now get the output in CSV format

- Added some new plugins (SAMParse, WinNT_CV, ProfileList, BitBucket, etc.), as well as made some minor updates to a couple of others, based on my own testing and use, as well as a suggestion from a user

This download includes all of the plugins from the previous download, plus the ones mentioned above. Installing this package is as simple a extracting the files from the zip archive into the same directory you used with the previous version.

A couple of notes and reminders on the use of these tools...

- RegRipper is NOT intended to be run on live Registry hive files - feel free to do so, but please...if it doesn't work, I already know that! =)

- If you find that RegRipper did not apparently work properly, or you think it didn't, then please feel free to contact me...but please also include the log file generated by RegRipper (ie, rr-.log). If at all possible, the actual hive file you were running against would be very helpful, but in most cases the log file should contain some useful info, albeit nothing customer- or case-specific.

- Keep in mind that while the edition of RegRipper you're using is fully functional, there is additional functionality that has been incorporated into the Advanced edition of the tool, such as support for selecting and using arbitrary plugins files, etc. I've included this in the if you have feature requests, please consult the FAQ and file named "regripper.pdf" first.

- Please be sure to read the documentation (FAQ, regripper.pdf) if you have any questions. I have received requests to provide plugins for USB removable storage devices...after I put in the effort to write and test the plugin, and included it in the distribution.

For those of you who have tried/used RegRipper, I hope you've found it as useful as I continue to find it just about every day. For those of you who have commented or provided feedback, I thank you very much for that.

Other stuff...
On a side note, I added an experimental '-g' switch to the version of rip.exe that I keep with the Advanced edition of RegRipper...this switch does some guessing as to what kind of hive file the analyst is pointing to. One of the things I've been toying with on the side, something requested by a friend, is the ability to parse not only a specific hive file, but to then access the Restore Points on XP, and run that same plugin against the appropriate hive file within each RP. I've got most of the code working, at this point it's simply a matter of tying it together and having the output in a readable format.

Free Analysis

What??!? "Free" (as in 'beer') analysis? A bit ago, I blogged about Forensic Analysis on the Cheap, and I wanted to revisit that topic, particularly to mention a couple of tools I've run across since then...

Event Logs
In an earlier post, I mentioned some tools you could use to perform Event Log analysis. I still like the functionality in EvtUI (although I may be seen as biased because I wrote it), but if tools like this scare you, there are other options available. For example, Event Log Explorer is a nice little little app, and you can obtain a free license for its use. In direct mode, it works just like EvtUI, accessing the event records directly within a .evt file extracted from an acquired image.

Registry Analysis
I have to say that I'm really partial to RegRipper and its associated CLI utility, rip.exe. A couple of minor tweaks, as well as some new plugins, both of which were recently added, make this an immensely useful (not to mention unique) tool.

When looking for things I may want/need to add as plugins to RegRipper, my favorite Registry Viewer to use is MiTeC's RFV. I can go through the hive file and look at things, and fire rip.exe off against it without having to unload the hive or anything like that. RFV is a great Registry Viewer that facilitates the development of plugins.

File Carving
I've mentioned scalpel before as a tool for file carving...XaberSoft provides a GUI interface for setting up the scalpel config file

Another useful tool for file carving is PhotoRec. Even though its intended for extracting image files, I'm sure that there are a number of folks out there interested in doing just that...

Other Tools
Shadow Explorer - I haven't had an opportunity to try this tool yet, but I'm told that it's great for recovering files using Vista's Volume Shadow Copy Service. If you can boot an acquired image using LiveView, and log into the running image, you may be able to get some useful information or recover some files using this tool.

Friday, April 18, 2008

Cutaway does Windows IR

The Security Ripcord site has a great new article on Windows IR, and using system resources to get the data you need.

I know that some folks are going to have an issue with using system resources (ie, DLLs, etc) when performing any kind of IR, but to be honest, I honestly believe (based on experience) that if more folks had stopped using that as a roadblock for doing any kind of response at all, there would likely be fewer instances of reported breaches, and breaches may have been less severe.

All incident response starts with the same basic elements and questions as any other system troubleshooting. The problem seems to start when admins and responders simply have no idea what it is they need to be looking at, or for. Don's article does a great job of bringing that to light, as well as providing a means of acquiring the necessary data. Not only does Don explain what is accessed and why, he also provides caveats about the artifacts left on the system as a result of the admin or responder's interactions with the system. This is very important, as anytime you access a live system, you're going to leave artifacts of one kind or another...being able to distinguish between your actions and the user's actions may be very important. Scripts such as what Don provided are self-documenting, in that all you have to do is ensure that you keep track of when (as in "what time") you ran the script, and then include a copy of the script along with your case notes.

A great big thanks and Semper Fi to Don for providing this article and script! It's information like this that's going to break down the barriers of inaction and provide for better response to all sorts of issues, large and small.

Tuesday, April 08, 2008

RegRipper on

I've posted RegRipper v2.0A Basic Edition to The archive includes the source and EXEs for RegRipper and rip.exe (as well as the required DLL), an FAQ, whitepaper, list of current plugins, etc.

Sunday, April 06, 2008

Bejtlich on IR, Forensics

Richard Bejtlich, of TaoSecurity fame, recently blogged about an article he'd written for CSO Magazine, entitled Computer Incident Detection, Response, and Forensics: the Basics. It's a very interesting article, and supports a great deal of what I've seen from various sources over the past year, as well as some of my own practical experience as an incident responder.

The biggest thing I picked up on is that here is Richard talking about how "pulling the plug" is not necessarily the immediate-action-of-choice these days...this is very true. For example, a system gets compromised and network logs indicate that there is a significant amount of traffic leaving that system (albeit the fact that the network logs do not contain content...). The first thing that most IT admins tend to do is take the system off-line (off the network), and in some cases even shut down or simply reboot the system. Then the big, $64,000 question that needs to be answered...for the CIO or for an external regulatory, what was going out? Was it some sort of homing beacon, or was it actual data (ie, sensitive data, as defined by CA's SB1386 or AB1298)?

In pulling the plug, other questions are also difficult to answer...was this system as stepping stone to other systems, or was itself attacked from another system? If so, what/where are those systems? more network connection I have query every system in the infrastructure, and because I shut this system down, I don't have a recognizable footprint to look for. =(

Had the first responders had the right tools and training available, they could have captured necessary data prior to taking those immediate actions.

One aspect of the article I don't agree with is the statement that prevention eventually fails. Ever since I was in the military, I had a problem with folks saying that something was failure when it was never proper implemented in the first place. While it's true that defenders have to protect all avenues of ingress and an attacker only needs to find one way in, incident analysts have seen enough intrusion incidents over the past couple of years to know that a great many infrastructures (small and large) have enough poorly configured systems (not rogue or unknown...all of these systems are known, and quite simply not properly configured) as to not have much in the way of defenses. I do agree that detection needs to be properly implemented alongside prevention, but I'd like to see prevention properly implemented before we simply rule it a failure.

Overall, the article is a very good read...and like many articles that make predictions that this is the Year of Whatever, we'll have to wait and see.

Saturday, April 05, 2008

Ripping the Registry w/ rip.exe

While I was developing the RegRipper, I found that I could use some means of testing plugins without having to fire up the RegRipper GUI each time, particularly if I just wanted to modify how the output was displayed...for example, once I got all the information I needed, say that I wanted to parse it and have it displayed based on the Registry key LastWrite times (so that it's easier to correlate to an incident timeline...). Do I want to fire things up all over again, or simply re-run the last command line?

So I wrote rip.exe, a small CLI utility that uses the same plugin structure as RegRipper, and lets me either run a single plugin against a hive file, or run an entire plugins file against a hive file. Here's what the syntax for rip.exe looks like:

Rip [-r Reg hive file] [-f plugin file] [-p plugin module] [-l] [-h]
Parse Windows Registry files, using either a single module, or a plugins file.
All plugins must be located in the "plugins" directory; default plugins file
used if no other filename given is "plugins\plugins".

-r Reg hive file...Registry hive file to parse
-f [plugin file]...use the plugin file (default: plugins\plugins)
-p plugin module...use only this module
-l ................list all plugins
-h.......................Help (print this information)

Ex: C:\>rr -r c:\case\system -f system
C:\>rr -r c:\case\ntuser.dat -p
C:\>rr -l

All output goes to STDOUT; use redirection (ie, > or >>) to output to a file.

copyright 2008 H. Carvey

Pretty cool. I even threw in a switch to just list all of the plugins in the plugins directory; the output includes the name of the plugin, the version, which hive file each plugin is for (ie, NTUSER.DAT, System, Software, etc.), and brief description of what the plugin does. Here are a couple of examples:

7. auditpol v.20080327 [Security]
- Get audit policy from the Security hive file

8. bho v.20080325 [Software]
- Gets Browser Helper Objects from Software hive

9. cmd_shell v.20080328 [Software]
- Gets shell open cmds for various file types

10. comdlg32 v.20080324 [NTUSER.DAT]
- Gets contents of user's ComDlg32 key

11. compdesc v.20080324 [NTUSER.DAT]
- Gets contents of user's ComputerDescriptions key

12. compname v.20080324 [System]
- Gets ComputerName value from System hive

13. devclass v.20080331 [System]
- Get USB device info from the DeviceClasses keys in the System hive

14. fw_config v.20080328 [System]
- Gets the Windows Firewall config from the System hive

So let's say that I have an image of a Windows system, and I've either extracted the Registry hive files from the image and placed them in a directory, or I've mounted the image file as a read-only file system using Mount Image Pro or VDKWin. If I want to take a cursory look at some things to sort of get an idea of what I'm looking at, I can run rip.exe to collect info for me:

C:\tools>rip rip -r d:\cases\ntuser.dat -p userassist

Let's say that I want to run an entire plugins file against a hive file...

C:\tools>rip rip -r f:\windows\system32\config\software -f software

Pretty straight-forward, simple, and quick. Very efficient, and keeps mistakes down. Rip.exe can also be incorporated into a batch file, to further enhance processing and reduce an analyst's interaction with the data even further.

Registry Analysis Myths

No, sorry...I don't have a lisp...

Based on a recent comment, it occurred to me that there are several myths regarding Registry analysis that are apparently accepted as fact...and I'd like to address those myths...

Myth #1
Registry analysis is time intensive.
Anything we don't understand is inherently "time intensive" due to the learning curve. However, think about when you were a teen-ager (for folks like me, that era is lost in the mists of time...) and you had a passionate desire to learn to drive. Learning to drive was time intensive, wasn't it? After all, in most cases, we didn't know how and had to learn...which took time (more so if you were learning to drive a stick). Leap forward to adulthood, and think about how "time intensive" it was to learn to do computer forensic analysis, either on your own or through vendor-specific training. Until you understand something, everything is time intensive. Maybe Blade said it best: When you understand the nature of a thing, you know what it's capable of.

Tools like the RegRipper remove the need for opening hive files by hand to search for specific keys, value names and data, and then, if necessary, translating them by hand. How cumbersome would it be to navigate to the UserAssist keys via RegEdit, and have to translate every value name (un-ROT-13) and then translate every FILETIME object? Eesh...I don't wanna think about it...b/c I can do it quickly by firing up the RegRipper, or just use rip.exe. Fast, efficient, and I get my output sorted based on the timestamps. Suh-weet!

Myth #2a
Registry analysis solves everything.
Not any other form of forensic analysis, Registry analysis has its own inherent limitations. For one, if the data isn't there, it can't be analyzed...kind of simplistic, I know, but thanks to shows like CSI, some folks think that computer forensics can show files copied to and from a hard drive, without the other piece of media. There are limits to everything.

Myth #2b
Registry analysis has absolutely no benefit.
Again, not true. Registry analysis can show things not evident through traditional forensic analysis, such as associating specific activities with a specific user account, or showing that certain files (by name) were viewed long after the files themselves have been deleted from the system and overwritten. The same is true with applications on the system...information about EXEs that had once been on the system can be found in the UserAssist, MUICache, App Paths, and possibly even in the Uninstall key values.

Registry analysis can also show that certain files had been accessed...not only that they had been, but possibly even when and how/in what manner, by a specific user. Sometimes, this information can't be found through normal ASCII text searches, because the data itself if stored as a binary data type, and must be parsed into something that is human readable.

More about the Registry...

While my recent posts have been about Registry analysis, I didn't want to ignore the work that has been done with regards to extracting Registry information (key, values, etc.) from other sources, such as RAM and process dumps, unallocated space, the pagefile, etc.

Moyix over at the Push The Red Button blog has posted some really good information lately on Registry cell index translation, even going back to his enumerating Registry hives post from Feb. He's got a great deal of excellent information in these posts that can be used to merge Registry and physical memory analysis.

Segue: While we're on the subject of memory analysis, check out this "Practical of "15 Minute Virus Analysis"" post from the ForensicZone...seems someone found a good use for lspm.exe. ;-)

Registry Slack
Also, there's a question of Registry slack...cells within a hive file that contain key or value data, but are not recognized by the MS API. This is different from unused keys and values that still exist after an application has been removed from the system...largely due to the fact that these keys and values may still be viewable via RegEdit or any other tool. What I'm referring to is this...Registry key cells contain pointers to other key cells, as well as basically, everything you see in most Registry viewers is a result of following links from root key, in much the same way as every file within an active file system will have a path back to the root directory. However, the question of Registry slack...cells within the hive file that may be valid key or value cells but are not linked into the visible Registry structure...still remains unanswered. Hopefully, though, not for long...there's a thesis student in Europe who has taken on the exercise of exploring this area.

Windows Oddities

Here are a couple of odd things about forensic analysis of Windows systems that I thought I'd share...

Windows Accounts
A user on one of the lists recently sent in an email with a question that I thought others might be interested in...well, interested in the question, and the answer...

The user said that they'd found profiles on an XP system with the following format for the directory names:


Evidently, according to this information on EvilBytes, this can occur when the user looses "Full Control" to their profile directory.

Fortunately, MS has something to say about this, as well...
Ch. 7 - Intro to Config and Mgmt
If another user with an account name jeffsmith logs on to the same Windows 2000 Professional–based computer from an identically named source (either a domain or local computer) and the SIDs of the two accounts are not the same, a new folder is created with an extension indicating how many times the user account name was used. This occurs when the user accounts are re-created and the user logs on to the same computer...

Also see:
How to restore a user profile in Windows 2000
How to restore a user profile in Windows 2003

I was looking up something related to running a checked build of netlogon.dll today and I ended up in the %SystemRoot%\Debug directory. I saw a couple of log files, one of them named "mrt.log". Evidently, this is an MS Malicious Software Removal Tool log file...follow the previous link to get a list of software that is detected and removed by MSRT. This can be useful information for a forensic examiner, particularly when coupled with any AV software that is installed on the get a version number, the date/time that it was last run, as well as the results. Say you're examining a system that has Symantec's product installed, as well as would then make sense to review the data available in these logs, and then use a disparate product when scanning for malware.

While looking at the mrt.log file, I noticed that in the same directory is a passwd.log file and thought that was curious. Not surprisingly I found NO information at MS about this file whatsoever...however, I did find one post that indicated that the file is used by lsass.exe to record information about the TSInternetUser account's password attempts, changes, etc. Granted, the post is six years old...but still, this may remain a valid use for the file. Additional posts found on Google (by searching the Web and Groups...) indicate that it may be associated with more than just the TSInternetUser account, but it definitely appears to be associated with the SamChangePasswordUser2 API.

If your passwd.log file has entries approximately every 24 hrs, associated with the TSInternetUser account, you may want to look to MS KB Q244057 for some useful info.

A Guide to Basic Computer Forensics

Tuesday, April 01, 2008

More Registry Analysis...

I think that in discussing Registry analysis, one of the shortcomings we're facing is the translation to the analyst of why something like this is (or can be) important, and how it can be used to benefit the analyst, as well as support an examination. After all, I think that most folks understand, perhaps somewhat intuitively, the usefulness of files within the active file system (as well as file metadata, such as MAC times), log file entries, etc. Where Registry analysis is falling short (from an adoption perspective) is (a) a solid understanding by the analyst of how this can benefit an exam, and (b) easy, intuitive tools for conducting Registry analysis.

Well, I think we've covered (b) pretty well...or, at the very least, started addressing it.

A short, Reader's Digest version of (a) is that the Registry holds a great deal of configuration information about the system, as well as information specific to the user's activities on the system. Much of this information is timestamped, as well (Note: recent experience shows that Win98/ME Registry keys do not enjoy the privilege of a LastWrite time...), making the Registry extremely useful and akin to a log file.

Now, Registry analysis will not benefit every exam, of course...each exam has it's own unique twists, and if you're a consultant, requirements. However, a great deal of Registry analysis is straightforward, simple, and easily accomplished...and in some cases can greatly benefit your exam. For example, consider this blog post by SynJunkie...a while back, I'd figured out that some AV vendors we're maybe passing some spurious info in their malware write-ups, and decided to look into the MUICache key. In the absence of any credible documentation from the vendor, some folks have found something very useful about this key.

Traditional file system-based computer forensic analysis may show the analyst that an image or movie is or was on a system...Registry analysis will show you who viewed it, and possibly even when. In the past, I've used Registry analysis to show that one employee was connecting to another employee's system and grabbing copies of her Trillian logs, and reading all of her conversations...I was even able to demonstrate that he'd viewed some of her log files and then deleted them, as well as the most recent time that he'd read one of those log files.