Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022  
Original source:  
Threat: Trojan.Ransom.Ryuk.A  
Vulnerability: Arbitrary Code Execution  
Description: The ransomware looks for and executes DLLs in its current directory. Therefore, we can potentially hijack a vuln DLL execute our own code, control and terminate the malware pre-encryption. Once loaded the exploit dll will check if the current directory is "C:\Windows\System32", if not we grab our process ID and terminate. All basic tests were conducted successfully in a virtual machine environment.  
Family: Ryuk  
Type: PE32  
MD5: 5ac0f050f93f86e69026faea1fbb4450  
Vuln ID: MVID-2022-0640  
Disclosure: 09/19/2022  
1) Compile the following C code as "urlmon.dll"  
2) Place the DLL in same directory as the ransomware  
3) Optional - Hide it: attrib +s +h "urlmon.dll"  
4) Run the malware  
#include "windows.h"  
//By malvuln  
//Purpose: Exploit Ryuk  
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 urlmon.c -m32  
//gcc -shared -o urlmon.dll urlmon.o -m32  
BOOL APIENTRY DllMain(HINSTANCE hInst, DWORD reason, LPVOID reserved){  
switch (reason) {  
MessageBox(NULL, "Ryuk\nPWNED By MALVULN", "Code Exec PoC", MB_OK);  
GetCurrentDirectory(MAX_PATH, TEXT(buf));  
int rc = strcmp("C:\\Windows\\System32", TEXT(buf));  
if(rc != 0){  
HANDLE handle = OpenProcess(PROCESS_TERMINATE, FALSE, getpid());  
if (NULL != handle) {   
TerminateProcess(handle, 0);  
return TRUE;  
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