Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/ca40998b5d62ee7f936537ff3de7993d.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Agent.bjev 
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: ca40998b5d62ee7f936537ff3de7993d
Vuln ID: MVID-2021-0297
Disclosure: 07/18/2021

Exploit/PoC:
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 /a Windupdt
 Volume in drive C has no label.

 Directory of C:\Windupdt

06/15/2012  12:11 AM           264,704 winupdate.exe
               1 File(s)        264,704 bytes


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