full-disclosure - [FD] Backdoor.Win32.DarkKomet.aspl / Insecure Permissions

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Message-ID: <CAAHK0WQL4=QGsVGVJ7d1Nd+2WzckwcJperjzbNLQ3s6HH_VAdg@mail.gmail.com>
Date: Mon, 30 Aug 2021 21:56:03 -0400
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] Backdoor.Win32.DarkKomet.aspl / Insecure Permissions

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/5c644104f96ccad7a8cf324c2e523530.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.DarkKomet.aspl
Vulnerability: Insecure Permissions
Description: The malware creates an insecure dir under c:\ drive and grants
change (C) permissions to the authenticated user group. Standard users can
rename the executables dropped by the malware to disable it or replace it
with their own executable. Then wait for a privileged user to logon to the
infected machine to potentially escalate privileges.
Type: PE32
MD5: 5c644104f96ccad7a8cf324c2e523530
Vuln ID: MVID-2021-0320
Dropped files: winupdate.exe
Disclosure: 08/30/2021

Exploit/PoC:
C:\>cacls Windupdt
C:\Windupdt 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:\>dir Windupdt
 Volume in drive C has no label.

 Directory of C:\Windupdt

07/05/2021  11:27 PM           245,760 winupdate.exe
               1 File(s)        245,760 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).

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