Date: Mon, 9 May 2022 00:34:53 -0400
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] APT28 FancyBear / Code Execution

Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source:
https://malvuln.com/advisory/d6751b148461e0f863548be84020b879.txt
Contact: malvuln13@...il.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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