Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024 Original source: https://malvuln.com/advisory/f917c77f60c3c1ac6dbbadbf366ddd30.txt Contact: [email protected] Media: twitter.com/malvuln 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:\Windows\System32", 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 Exploit/PoC: 1) Download RansomLord v3 https://github.com/malvuln/RansomLord 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. Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).