Ransom.LockBit DLL Hijacking

`Discovery / credits: Malvuln - malvuln.com (c) 2022  
Original source: https://malvuln.com/advisory/96de05212b30ec85d4cf03386c1b84af.txt  
Contact: [email protected]  
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;  
}  
  
  
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`