Discovery / credits: Malvuln - malvuln.com (c) 2022
Original source: https://malvuln.com/advisory/8201ba6b542fc91c004110b2fc5395aa.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Prosti.b
Vulnerability: Insecure Permissions
Description: The malware writes a ".dll" PE file 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: 8201ba6b542fc91c004110b2fc5395aa
Vuln ID: MVID-2022-0492
Disclosure: 02/16/2022


Exploit/PoC:
C:\>cacls Backdoor.dll
C:\Backdoor.dll BUILTIN\Administrators:(ID)F
                NT AUTHORITY\SYSTEM:(ID)F
                BUILTIN\Users:(ID)R
                NT AUTHORITY\Authenticated Users:(ID)C


C:\>dir Backdoor.dll
 Volume in drive C has no label.

 Directory of C:\

02/13/2022  02:33 AM           117,248 Backdoor.dll
               1 File(s)        117,248 bytes
               0 Dir(s)  26,682,523,648 bytes free

C:\>type Backdoor.dll
MZP          ╕       @


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