Backdoor.Win32.Mechbot.a / Insecure Permissions

[malvuln <malvuln13 () gmail com>]

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/8c9e7906d0ad5d0f2267be0057f2a8e3.txt
Contact: malvuln13 () gmail com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Mechbot.a
Vulnerability: Insecure Permissions
Description: The malware creates a dir with insecure permissions under c:\
drive granting change (C) permissions to the authenticated user group.
Standard users can rename the executable 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: 8c9e7906d0ad5d0f2267be0057f2a8e3
Vuln ID: MVID-2021-0417
Disclosure: 12/11/2021


Exploit/PoC:
C:\>cacls "TitanZone BOT"
C:\TitanZone BOT 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 "TitanZone BOT"
 Volume in drive C has no label.

 Directory of C:\TitanZone BOT

06/15/2003  11:24 AM               591 checkmech
06/15/2003  11:24 AM            21,854 configure
11/19/2021  12:13 AM    DIR          CONTRIB
05/10/2003  02:07 PM           201,216 CYGWIN1.DLL
05/10/2003  02:07 PM             4,305 GENUSER
07/02/2003  08:44 PM                35 LinkEvents
06/15/2003  11:24 AM             1,391 Makefile
05/10/2003  02:07 PM            22,882 mech.help
07/02/2003  08:40 PM                 6 MECH.PID
07/02/2003  08:45 PM             2,464 MECH.SET
05/10/2003  02:07 PM               796 MKINDEX
11/19/2021  12:13 AM    DIR          randfiles
11/19/2021  12:13 AM    DIR          SRC
06/26/2003  09:09 PM               213 titanzone.bat
11/19/2021  12:13 AM    DIR          TOOLS
05/10/2003  02:07 PM           192,512 WinMech.exe
07/02/2003  08:45 PM               155 winmech.users


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