Saturday, February 27, 2021

Backdoor.Win32.Azbreg.amw Insecure Permissions

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/5eb58198721d4ded363e41e243e685cc.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Azbreg.amw
Vulnerability: Insecure Permissions
Description: The backdoor creates an insecure hidden dir named "MSDCSC" granting change (C) permissions to the authenticated user group. Standard users can rename the malware and reboot to disable it or replace with their own executable to escalate privileges when a privileged user logs on to the infected machine.
Type: PE32
MD5: 5eb58198721d4ded363e41e243e685cc
Vuln ID: MVID-2021-0113
Dropped files: msdcsc.exe
Disclosure: 02/25/2021


Exploit/PoC:
#include "windows.h"

void main(void){

system("attrib -h C:\\MSDCSC\\msdcsc.exe");
system("RENAME C:\\MSDCSC\\msdcsc.exe 13");

Sleep(1000);

puts("[+] Disabled by renaming C:\\MSDCSC\\msdcsc.exe to 13 ...\n");

Sleep(1000);

puts("[+] Backdoor.Win32.Azbreg.amw PWNED!");
puts("[+] MD5: 5eb58198721d4ded363e41e243e685cc");
puts("[+] By Malvuln");
system("pause");

}

C:\>cacls \MSDCSC
C:\MSDCSC 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 /a \MSDCSC

Directory of C:\MSDCSC

07/13/2012 01:35 AM 755,712 msdcsc.exe
1 File(s) 755,712 bytes


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