Ransom.LockBit / DLL Hijacking

2022.05.02
us malvuln (US) us
Risk: Medium
Local: Yes
Remote: No
CVE: N/A
CWE: N/A

Discovery / credits: Malvuln - malvuln.com (c) 2022 Original source: https://malvuln.com/advisory/96de05212b30ec85d4cf03386c1b84af.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Ransom.LockBit Vulnerability: DLL Hijacking Description: LockBit ransomware looks for and executes DLLs in its current directory. This can potentially allow us to execute our own code, control and terminate the malware pre-encryption. The exploit dll will check if the current directory is "C:\Windows\System32", if not we grab our process ID and terminate. Endpoint protection systems and or antivirus can potentially be killed prior to executing malware, but this method cannot as theres nothing to kill the DLL just lives on disk waiting. All basic tests were conducted successfully in a virtual machine environment. Family: LockBit Type: PE32 MD5: 96de05212b30ec85d4cf03386c1b84af Vuln ID: MVID-2022-0572 Disclosure: 05/02/2022 Video PoC URL: https://www.youtube.com/watch?v=3i6tv4cpfSc Exploit/PoC: 1) Compile the following C code as "netapi32.dll" 2) Place the DLL in same directory as Lockbit ransomware 3) Optional - Hide it: attrib +s +h "netapi32.dll" 4) Run Lockbit PE file #include "windows.h" #include "stdio.h" //By malvuln - 5/1/2022 //Vuln: DLL Hijacking //Target: Lockbit Ransomware //MD5: 96de05212b30ec85d4cf03386c1b84af /** DISCLAIMER: Author is NOT responsible for any damages whatsoever by using this software or improper malware handling. By using this code you assume and accept all risk implied or otherwise. **/ //gcc -c netapi32.c -m32 //gcc -shared -o netapi32.dll netapi32.o -m32 BOOL APIENTRY DllMain(HINSTANCE hInst, DWORD reason, LPVOID reserved){ switch (reason) { case DLL_PROCESS_ATTACH: MessageBox(NULL, "Code Exec", "by malvuln", MB_OK); TCHAR buf[MAX_PATH]; GetCurrentDirectory(MAX_PATH, TEXT(buf)); //printf("Current directory: %s\n", buf); //check the path, netapi32.dll is sideloaded by lockbit int rc = strcmp("C:\\Windows\\System32", TEXT(buf)); if(rc != 0){ HANDLE handle = OpenProcess(PROCESS_TERMINATE, FALSE, getpid()); if (NULL != handle) { TerminateProcess(handle, 0); CloseHandle(handle); } } break; } return TRUE; } 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).


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