Backdoor.Win32.DarkKomet.irv Insecure Permissions

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/341b2c3222122bd25c8509fc09534dec.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Backdoor.Win32.DarkKomet.irv  
Vulnerability: Insecure Permissions   
Description: DarkKomet.irv creates an insecure hidden dir named "updter" under c:\ drive and drops executable "updt.exe". The backdoor grants change (C) permissions to the authenticated user group for the "updter" dir. Standard users can rename the malware to disable it or replace with their own executable. Then wait for a privileged user to logon to the infected machine to potentially escalate privileges.  
Type: PE32  
MD5: 341b2c3222122bd25c8509fc09534dec  
Vuln ID: MVID-2021-0118  
Dropped files: updt.exe  
Disclosure: 03/02/2021  
  
  
Exploit/PoC:  
gcc -c DarkKomet_Exploit.c  
gcc -o DarkKomet_Exploit.exe DarkKomet_Exploit.o  
  
"DarkKomet_Exploit.c"  
  
#include "windows.h"  
  
void main(void){  
  
system("attrib -s -h C:\\updter\\updt.exe");  
system("rename C:\\updter\\updt.exe 13");  
  
Sleep(1000);  
  
puts("[+] Disabled by renaming C:\\updter\\updt.exe to 13 ...\n");  
  
Sleep(1000);  
  
puts("[+] Backdoor.Win32.DarkKomet.irv PWNED!");  
puts("[+] MD5: 341b2c3222122bd25c8509fc09534dec");  
puts("[+] By Malvuln");  
system("pause");  
}  
  
C:\>cacls C:\updter BUILTIN\Administrators:(OI)(CI)(ID)F  
NT AUTHORITY\SYSTEM:(OI)(CI)(ID)F  
BUILTIN\Users:(OI)(CI)(ID)R  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
  
  
C:\>cd updter  
  
C:\updter>dir  
Volume in drive C has no label.  
  
Directory of C:\updter  
  
File Not Found  
  
C:\updter>dir /a  
Volume in drive C has no label.  
  
Directory of C:\updter  
  
06/17/2012 12:59 AM 827,392 updt.exe  
1 File(s) 827,392 bytes  
  
  
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`