Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/341b2c3222122bd25c8509fc09534dec.txt Contact: malvuln13@gmail.com 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 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).