Lockbit version 3.0 ransomware looks for and executes DLLs in its current directory. Therefore, we can hijack a DLL, in this case “RstrtMgr.dll”, execute our own code, and terminate the malware pre-encryption. The exploit DLL checks if the current directory is “C:WindowsSystem32” and if not we grab our process ID and terminate. All basic tests were conducted successfully in a virtual machine environment.
Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source: https://malvuln.com/advisory/38745539b71cf201bb502437f891d799_B.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Ransom Lockbit 3.0
Vulnerability: Code Execution
Description: The ransomware apparently now requires a password to execute as noted by "@vxunderground" E.g. "-pass db66023ab2abcb9957fb01ed50cdfa6a". Lockbit looks for and executes DLLs in its current directory. Therefore, we can hijack a vuln DLL in this case "RstrtMgr.dll", execute our own code and terminate the malware pre-encryption. The exploit dll checks if the current directory is "C:WindowsSystem32", if not we grab our process ID and terminate. All basic tests were conducted successfully in a virtual machine environment.
Family: Lockbit
Type: PE32
MD5: 38745539b71cf201bb502437f891d799
Vuln ID: MVID-2022-0621
Disclosure: 07/04/2022
Video PoC URL: https://www.youtube.com/watch?v=tAXrRcsnzjY
Exploit/PoC:
1) Compile the following C code as "RstrtMgr.dll"
2) Place the DLL in same directory as Lockbit 3.0
3) Optional - Hide it: attrib +s +h "RstrtMgr.dll"
4) Run Lockbit 3.0 {04830965-76E6-6A9A-8EE1-6AF7499C1D08}.exe -k LocalServiceNetworkRestricted -pass db66023ab2abcb9957fb01ed50cdfa6a
#include "windows.h"
//By malvuln - 7/4/2022
//Purpose: RCE in Lockbit 3.0 ransomware
//MD5: 38745539b71cf201bb502437f891d799
//gcc -c RstrtMgr.c -m32
//gcc -shared -o RstrtMgr.dll RstrtMgr.o -m32
/** 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.
**/
BOOL APIENTRY DllMain(HINSTANCE hInst, DWORD reason, LPVOID reserved){
switch (reason) {
case DLL_PROCESS_ATTACH:
MessageBox(NULL, "Ransom Lockbit 3.0 aka LockShitnPWNED by Malvuln", "Code Exec PoC", MB_OK);
TCHAR buf[MAX_PATH];
if(GetCurrentDirectory(MAX_PATH, buf))
if(strcmp("C:WindowsSystem32", buf) != 0){
HANDLE handle = OpenProcess(PROCESS_TERMINATE, FALSE, getpid());
if (NULL != handle) {
TerminateProcess(handle, 0);
CloseHandle(handle);
}
}
break;
}
return TRUE;
}
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