Trojan-Dropper.Win32.Dycler.yhb malware suffers from an insecure permissions vulnerability.
e29fc69ff4dda14c4e8383ddc91f5ffdDiscovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/04a5a52f12d2a130bb88f98c3bc14aa8.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Trojan-Dropper.Win32.Dycler.yhb
Vulnerability: Insecure Permissions
Description: Dycler.yhb creates a dir named "RECYCLER" under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename the "cft_mon.exe" 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: 04a5a52f12d2a130bb88f98c3bc14aa8
Vuln ID: MVID-2021-0140
Dropped files: cft_mon.exe
Disclosure: 03/23/2021
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:\>cd \RECYCLER
C:\RECYCLER>dir /a
Volume in drive C has no label.
Directory of C:\RECYCLER
06/17/2012 01:56 AM 463,591 cft_mon.exe
1 File(s) 463,591 bytes
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