HEUR.Backdoor.Win32.Agent.gen / Insecure Permissions

[malvuln <malvuln13 () gmail com>]

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/db0b3f4aeccb8d26f14b915a9e2529b4.txt
Contact: malvuln13 () gmail com
Media: twitter.com/malvuln

Threat: HEUR.Backdoor.Win32.Agent.gen
Vulnerability: Insecure Permissions
Description: The malware creates a dir with insecure permissions under c:\
drive and grants 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: db0b3f4aeccb8d26f14b915a9e2529b4
Vuln ID: MVID-2021-0282
Dropped files: xm86.exe
Disclosure: 07/12/2021

Exploit/PoC:
C:\Chrome\XMR2>dir
 Volume in drive C has no label.

 Directory of C:\Chrome\XMR2

03/18/2018  03:26 AM         1,731,080 xm86.exe
               1 File(s)      1,731,080 bytes

C:\Chrome\XMR2>cacls \Chrome
C:\Chrome 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


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