Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/001fc372acc853aa1cf92588a43a7deb.txt
Contact: malvul...@gmail.com
Media: twitter.com/malvuln
Threat: Virus.Win32.Renamer.a
Vulnerability: Insecure Permissions
Description: The malware creates an 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: 001fc372acc853aa1cf92588a43a7deb
Vuln ID: MVID-2021-0352
Dropped files: GUESSNUM.EXE
Disclosure: 10/04/2021
Exploit/PoC:
C:\>cacls "RECYCLER.{645FF040-5081-101B-9F08-00AA002F954E}"
C:\RECYCLER.{645FF040-5081-101B-9F08-00AA002F954E}
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.{645FF040-5081-101B-9F08-00AA002F954E}"
Volume in drive C has no label.
Directory of C:\RECYCLER.{645FF040-5081-101B-9F08-00AA002F954E}
06/17/2012 06:06 AM 818,211 GUESSNUM.EXE
1 File(s) 818,211 bytes
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