Backdoor.Win32.GTbot.c malware suffers from an insecure permissions vulnerability.
f9197ea213a468afd052ecf492b6f205Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/8c2acfcc60dda52db9bd9a934284b673.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Backdoor.Win32.GTbot.c
Vulnerability: Insecure Permissions
Description: GTbot creates an insecure dir called "WINNT" under c:\ drive and grants change permissions (C) to the authenticated user group. Standard users can rename the malware to disable it or replace with their own executable. Then wait for a privileged user to logon to the infected machine to potentially escalate privileges.
Type: PE32
MD5: 8c2acfcc60dda52db9bd9a934284b673
Vuln ID: MVID-2021-0122
Dropped files: esman.exe, seman.exe
Disclosure: 03/06/2021
Exploit/PoC:
C:\>cacls WINNT
C:\WINNT 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 WINNT
C:\WINNT>dir
Volume in drive C has no label.
Directory of C:\WINNT
03/02/2021 07:44 K0L4B0R451 <DIR> SYSTEM32
0 File(s) 0 bytes
3 Dir(s) 57,185,968,128 bytes free
C:\WINNT>cd SYSTEM32
C:\WINNT\SYSTEM32>dir
Volume in drive C has no label.
Directory of C:\WINNT\SYSTEM32
04/26/2006 12:06 K0L4B0R451 33,100 esman.exe
04/26/2006 12:07 K0L4B0R451 20,408 seman.exe
2 File(s) 53,508 bytes
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