Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/20863ba09c31037b1b3220fc6da100e1.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Neakse.bit
Vulnerability: Insecure Permissions
Description: The malware creates two insecure dirs housing DLLs 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: 20863ba09c31037b1b3220fc6da100e1
Vuln ID: MVID-2021-0238
Disclosure: 06/06/2021

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

 Directory of C:\codecs

04/06/2004  12:04 AM           548,919 colorcvt.dll
04/06/2004  12:05 AM            65,602 cook.dll
04/06/2004  12:07 AM           266,306 erv3.dll
04/06/2004  12:08 AM           479,298 erv4.dll
04/06/2004  12:05 AM           155,702 ralf.dll
04/06/2004  12:05 AM           102,465 sipr.dll
               6 File(s)      1,618,292 bytes

C:\>cacls common
C:\common 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 common
 Volume in drive C has no label.

 Directory of C:\common

12/06/2002  02:02 PM           395,776 encn3260.dll
04/06/2004  12:08 AM           368,732 rembrdcst.dll
               2 File(s)        764,508 bytes


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