Daily Blog #758: Sunday Funday 2/23/25

 

Hello Reader,

It's Sunday! This week's challenge is all about the windows search index! While we have parsers that support its contents its unclear to me when the database is updated/cleared when a file is deleted. Let's see what you all can do!

The Prize:

$100 Amazon Giftcard

The Rules:

1. You must post your answer before Friday 2/28/25 7PM CST (GMT -5)
2. The most complete answer wins
3. You are allowed to edit your answer after posting
4. If two answers are too similar for one to win, the one with the earlier posting time wins
5. Be specific and be thoughtful
6. Anonymous entries are allowed, please email them to dlcowen@gmail.com. Please state in your email if you would like to be anonymous or not if you win.
7. In order for an anonymous winner to receive a prize they must give their name to me, but i will not release it in a blog post
8. AI assistance is welcomed but if a post is deemed to be entirely AI written it will not qualify for a prize. 

The Challenge:

 On a Windows 11 or Windows 10 system:

1. Make sure windows search is enabled

2. Create files with unique phrases such as "This is the smoking gun"

3. Make sure the files are indexed and present in the windows search db

4. Delete the document and determine what the trigger method is and the timing for the contents to be deleted from the search database

Bonus: Determine if the deleted records are recoverable

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Daily Blog #757: Solution Saturday 2/22/25

 

Hello Reader,

  This week the real question is, can anyone stop Ilya Kobzar's winning streak? Here again is he back with another winning answer and some very thorough research all about what happens when credentials are taken via IMDS on AWS.

The Challenge:

 AWS IAM Roles are often targeted by threat actors after they get access to a running virtual machine. While AWS IMDS v2 may prevent some attacks the functionality is still there and is being actively exploited to get credentials and act as a service or role. In this challenge I want you to try the following and document what logs are left that could be used to detect or determine these actions occurred. 

1. Retrieve a temporary AWS access key credential from IMDS v1

2. Retrieve a temporary AWS access key credential from IMDS v2

3. Use the temporary access key within an AWS vm

4. Use the temporary access key from outside of AWS

From all four scenarios determine what logs are created.

bonus: Try and document other scenarios of theft and use and additional sources of evidence.  

The winning answer:

https://www.ilyakobzar.com/p/ec2-iam-role-sts-credentials-compromise

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Daily Blog #756: Forensic test kitchen, using the AWS CloudTrail Downloader v2!

 

Hello Reader,

Today I decided to do a live demonstration of how the AWS CloudTrail Downloader v2 from our FOR509 class works! So I fired it up and showed off all the new features like AWS profile support and most importantly resume functionality! I hope you like it!

 

 

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Daily Blog #755: A new blog is born!

 

Hello Reader,

 It's always great when new people start blogging, and Evan Anderson has started a new blog! His blog Offensive Context is all about offensive security techniques and applied leanings.  Evan and I have known each other for a long time and have done National CCDC redteaming together for over 15 years. So if you are looking to learn more about how threat actors actually work Evan's blog is a great place to learn!

https://www.offensivecontext.com/abusing-dns-part-1-how-does-dns-do-what-it-do/

https://www.offensivecontext.com/simple-python-tricks/

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Daily Blog #754: Pagefile carving with Page Brute

 

Hello Reader,

I’m often surprised by how many effective open source DFIR tools are overlooked. One of my favorites is page_brute. This tool tackles a tricky problem: parsing logical data chunks from the page file without accidentally merging memory segments from different programs.

Page_brute accomplishes this elegantly by carving the page file into segments equal to a single memory page. It then applies YARA rules to categorize each chunk. I mainly use it to recover AJAX fragments and other temporary web objects that never make it to disk. Since the content I’m after is usually small enough to fit within one memory page, this approach works exceptionally well for webmail investigations.

If you’re looking for a reliable method to recover and categorize page file contents, I highly recommend giving page_brute a try: GitHub - matonis/page_brute.

 

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Daily Blog #753: Windows hello challenge part 4

 

Hello, Reader,

The bonus question in this challenge asked where Windows stores the biometric data used for facial recognition or fingerprint authentication. It turns out that this information is kept in a database located at:

\Windows\System32\WinBioDatabase

Inside this folder, you’ll find files named with GUIDs and a .DAT extension, for example:

DC576DA6-D676-4A15-906D-C0CEAF949543.DAT

These files contain an encrypted and hashed version of a user’s identity that Windows uses for system authentication. This process is part of the Windows Biometric Framework. For more details, check out the Biometric Framework Overview on Microsoft Learn.

The encryption key being used remains unclear, and it’s possible that these keys are stored in a TPM chip. I’ll take a closer look at this file in my next post to see if the Data Protection API is also being utilized.

Stay tuned!

 

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Daily Blog #752: Windows hello challenge part 3 fingerprints

 

Hello Readers,

Believe it or not, I recently purchased a Windows Hello-compatible fingerprint reader purely to test its capabilities and examine the logs it generates. I’m pleased to report that the investment paid off—there’s now an event log entry in Microsoft-Windows-Biometrics that confirms a successful fingerprint-based authentication.

Here’s the log entry it's event id 1004:

The Windows Biometric Service successfully identified <hostname>\<username> (S-1-5-21-3400467401-1001) using sensor: VeriMark DT Fingerprint Key (USB\VID_047D&PID_00F2&MI_01\7&163AA6B8&0&0001).

Much like facial recognition, this distinct log entry clearly indicates that a person (or someone who managed to spoof the sensor) was present at the keyboard.

 

 

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Daily Blog #751: Sunday Funday 2/16/25

 

Hello Reader,

It's Sunday! This week's challenge is all about whats left behind when someone is able to get a temporary access key from an IAM role in AWS. Let's see who is able to build out the best detection set!

The Prize:

$100 Amazon Giftcard

The Rules:

1. You must post your answer before Friday 2/21/25 7PM CST (GMT -5)
2. The most complete answer wins
3. You are allowed to edit your answer after posting
4. If two answers are too similar for one to win, the one with the earlier posting time wins
5. Be specific and be thoughtful
6. Anonymous entries are allowed, please email them to dlcowen@gmail.com. Please state in your email if you would like to be anonymous or not if you win.
7. In order for an anonymous winner to receive a prize they must give their name to me, but i will not release it in a blog post
8. AI assistance is welcomed but if a post is deemed to be entirely AI written it will not qualify for a prize. 

The Challenge:

 AWS IAM Roles are often targeted by threat actors after they get access to a running virtual machine. While AWS IMDS v2 may prevent some attacks the functionality is still there and is being actively exploited to get credentials and act as a service or role. In this challenge I want you to try the following and document what logs are left that could be used to detect or determine these actions occurred. 

1. Retrieve a temporary AWS access key credential from IMDS v1

2. Retrieve a temporary AWS access key credential from IMDS v2

3. Use the temporary access key within an AWS vm

4. Use the temporary access key from outside of AWS

From all four scenarios determine what logs are created.

bonus: Try and document other scenarios of theft and use and additional sources of evidence. 

Read More