Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024
Original source:
Media Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024
Original source:

Threat: TrojanSpy.Win64.EMOTET.A
Vulnerability: Arbitrary Code Execution
Description: The malware looks for and executes a x64-bit "CRYPTBASE.dll" PE file in its current directory. Therefore, we can hijack the DLL and execute our own code to intercept and terminate the malware. Once loaded the exploit dll will check if the current directory is "C:WindowsSystem32", if not we grab our process ID and terminate. Leverage RansomLord v3 for DLL generation, while written as a proof-of-concept to specifically defeat ransomware, it can also be used to generate DLLs to try an exploit other types of malwares. All basic tests were conducted successfully in a virtual machine environment.
Family: EMOTET
Type: PE64
MD5: f917c77f60c3c1ac6dbbadbf366ddd30
SHA256: b76fbc81bbb7f3108d27d9da9e2646aeb3769fba62bf7961f79306812de3486c
Vuln ID: MVID-2024-0684
Disclosure: 05/14/2024

1) Download RansomLord v3
2) Locate the x64 CRYPTBASE.dll entry using the -m flag (DLL Map)
3) Use -g flag (Generate Exploit) to output an x64 DLL CRYPTBASE.dll, based on an existing vulnerable malware in the victims list.
4) (Optional) -e flag to setup Windows event IOC logging in the registry, this will log the SHA256 hash, full path and filename.

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