Extracting credentials from Windows minidumps

// Scenario Overview

In a penetration test or incident response, you may encounter Windows systems with compromised processes. Sometimes these processes are terminated, but their memory can still hold valuable artifacts like credentials. Mini dumps, which are lightweight representations of a process's memory, can be leveraged for this purpose.

// Setting Up Your Environment

To extract credentials from minidumps, you’ll need a few tools. Install the following on your analysis machine:

1. WinDbg: This is part of the Windows Debugging Tools. You can download it as part of the Windows SDK. 2. DumpCheck: Useful for validating dump files. It can be found in the Sysinternals suite. 3. Mimikatz: This tool will help extract passwords and hashes from memory.

Installation Example

For installing Mimikatz, you can clone its repository:

git clone https://github.com/gentilkiwi/mimikatz.git

// Acquiring Minidump Files

To analyze a running process, you need to capture its minidump. Use the following command from an elevated command prompt to create a minidump of a specific process:

procdump -ma <PID> <path_to_dump_file>.dmp

• <PID>: Replace this with the Process ID of the target process.
• <path_to_dump_file>: Specify where you want the dump saved.

Workflow Steps

1. Identify the target process using Task Manager, Process Explorer, or via command line:

   tasklist

Note the PID of the process you want to analyze.

2. Capture the minidump using procdump:

   procdump -ma <PID> dumpfile.dmp

Ensure you run this command with administrative privileges.

3. Validate the dump file using DumpCheck:

   DumpChk.exe <path_to_dump_file>.dmp

Check for any errors that may indicate an incomplete dump.

// Analyzing the Minidump with WinDbg

Once you have the valid minidump file, open it in WinDbg. The debugging process involves a few commands to retrieve the credentials:

1. Load the dump file:

   File -> Open Crash Dump

Locate your .dmp file and open it.

2. Set the correct symbol path:

   .sympath srv*C:\symbols*https://msdl.microsoft.com/download/symbols

This ensures you have the necessary symbols to analyze the dump.

3. Run the following command to load the process:

   !analyze -v

This will provide an overview of the process state at the time of the dump.

4. Search for the relevant credential data. For example, to find credentials stored in LSASS, use:

   !process 0 0

Then identify the address of the LSASS process and query it for credentials, typically in the Process and Thread sections.

5. Use Mimikatz within WinDbg to extract passwords. Load Mimikatz in WinDbg:

   !load <path_to_mimikatz.dll>

Then extract the credentials:

   sekurlsa::minidump <path_to_dump_file>.dmp
   sekurlsa::dumpcerts

This extracts any credentials stored in the LSASS dump.

// Errors and Troubleshooting

If you encounter issues:

• Ensure you have permissions to access the process and capture dumps.
• Verify the dump file is not corrupted.
• Check if the target process is still in memory or actively running.

Be wary of antivirus and endpoint protection solutions that may flag or block these actions.

// Defensive Considerations

Extracting credentials from minidumps is a potent technique for attackers. To defend against such exploits, consider the following:

• Implement strict access controls on sensitive processes like LSASS.
• Regularly update and patch systems to minimize vulnerabilities.
• Monitor for unusual process behaviors or unauthorized dump captures.

// Checklist for Extracting Credentials

• [ ] Identify target process.
• [ ] Capture minidump using Procdump.
• [ ] Validate dump file with DumpCheck.
• [ ] Open dump in WinDbg and set symbols.
• [ ] Load Mimikatz and extract credentials.

This method of extracting credentials can be a double-edged sword. With appropriate controls and oversight, it can be invaluable in incident response scenarios while also being a reminder of the importance of securing sensitive processes and data.

--- // FIELDOPS REPORT AUTHORIZED BY: Rachel H. //