Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/e4737fb6c231bfb84d1a55ec2fb61641.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Worm.Win32.Recyl.dp
Vulnerability: Insecure Permissions 
Description: creates a dir named "RECYCLER" 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: e4737fb6c231bfb84d1a55ec2fb61641
Vuln ID: MVID-2021-0143
Dropped files: abcd.exe, cft_mon.exe, ctf_mon.exe
Disclosure: 03/24/2021


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

 Directory of C:\RECYCLER

10/23/2012  04:56 AM            61,952 abcd.exe
07/06/2012  04:17 PM           886,669 cft_mon.exe
11/14/2012  12:11 PM           861,137 ctf_mon.exe
03/24/2021  03:11 PM             1,388 InstallLog.log


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