Headline
Win32.Ransom.BlueSky MVID-2022-0632 Code Execution
The BlueSky Win32.Ransom.BlueSky ransomware looks for and executes arbitrary DLLs in its current working directory. Therefore, we can hijack a DLL, execute our own code, and control and terminate the malware pre-encryption. The exploit DLL checks if the current directory is “C:\Windows\System32” and if not we grab our own process ID and terminate. All basic tests were conducted successfully in a virtual machine environment.
Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022Original source: https://malvuln.com/advisory/961fa85207cdc4ef86a076bbff07a409.txtContact: [email protected]: twitter.com/malvulnThreat: Win32.Ransom.BlueSkyVulnerability: Arbitrary Code ExecutionDescription: The BlueSky ransomware looks for and executes arbitrary DLLs in its current working directory. Therefore, we can hijack a vuln DLL, execute our own code, control and terminate the malware pre-encryption. The exploit dll checks if the current directory is "C:\Windows\System32", if not we grab our own process ID and terminate. All basic tests were conducted successfully in a virtual machine environment.Family: BlueSkyType: PE32MD5: 961fa85207cdc4ef86a076bbff07a409Vuln ID: MVID-2022-0632Disclosure: 08/13/2022PoC Video URL: https://www.youtube.com/watch?v=osuS8GjdERMExploit/PoC:1) Compile the following C code as "CRYPTSP.dll" 32-bit2) Place the DLL in same directory as the vuln BlueSky ransomware3) Run malware#include "windows.h"//By malvuln - August 2022//Purpose: PWN BlueSky ransomware MD5: 961fa85207cdc4ef86a076bbff07a409//gcc -c CRYPTSP.c -m32//gcc -shared -o CRYPTSP.dll CRYPTSP.o -m32/** DISCLAIMER:Author is NOT responsible for any damages whatsoever by using this software or improper malwarehandling. 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, "BlueSky Ransom\nPWNED!!! by Malvuln", "Code Exec PoC", MB_OK); TCHAR buf[MAX_PATH]; if(GetCurrentDirectory(MAX_PATH, buf)) if(strcmp("C:\\Windows\\System32", buf) != 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).