Trojan-Dropper.Win32.Demp.rft Insecure Permissions ≈ Packet Storm

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/db01783710e0c5aff92156a0e76deade.txt
Contact: Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser.
Media: twitter.com/malvuln

Threat: Trojan-Dropper.Win32.Demp.rft
Vulnerability: Insecure Permissions
Description: The specimen creates a dir named "tmp" under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename the "DaumCleans.exe" 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: db01783710e0c5aff92156a0e76deade
Vuln ID: MVID-2021-0138
Dropped files: DaumCleans.exe
Disclosure: 3/20/2021

Exploit/PoC:
C:\>cacls tmp
C:\tmp 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 tmp

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

Directory of C:\tmp

03/20/2021 09:27 PM 38,824 DaumCleans.exe
1 File(s) 38,824 bytes

#include "windows.h"

void main(void){

system("rename C:\\tmp\\DaumCleans.exe 13");

puts("[+] Disabled by renaming C:\\tmp\\DaumCleans.exe to 13 ...");
puts("[+] Reboot your machine");

Sleep(1000);

puts("[+] Trojan-Dropper.Win32.Demp.rft PWNED!");
puts("[+] MD5: db01783710e0c5aff92156a0e76deade");
puts("[+] By Malvuln");
system("pause");

}

Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).