VULHUB ™

Petya ransomware looks for and loads a DLL named "wow64log.dll" in Windows\System32. Therefore, we can drop our own DLL to intercept and terminate the malware pre-encryption. The exploit DLL will simply display a Win32API message box and call exit(). The exploit DLL must export the "InterlockedExchange" function or it fails with an error. We do not need to rely on hash signature or third-party products as the malware will do the work for us. Endpoint protection systems and or antivirus can potentially be killed prior to executing malware, but this method cannot as there's nothing to kill the DLL that just lives on disk waiting. From a defensive perspective you can add the DLLs to a specific network share containing important data as a layered approach. All basic tests were conducted successfully in a virtual machine environment.

Petya ransomware looks for and loads a DLL named "wow64log.dll" in Windows\System32. Therefore, we can drop our own DLL to intercept and terminate the malware pre-encryption. The exploit DLL will simply display a Win32API message box and call exit(). The exploit DLL must export the "InterlockedExchange" function or it fails with an error. We do not need to rely on hash signature or third-party products as the malware will do the work for us. Endpoint protection systems and or antivirus can potentially be killed prior to executing malware, but this method cannot as there's nothing to kill the DLL that just lives on disk waiting. From a defensive perspective you can add the DLLs to a specific network share containing important data as a layered approach. All basic tests were conducted successfully in a virtual machine environment.