Discovery / credits: Malvuln - (c) 2021  
Original source:  
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  
C:\>cacls tmp  
C:\tmp BUILTIN\Administrators:(OI)(CI)(ID)F  
NT AUTHORITY\Authenticated Users:(ID)C  
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(ID)C  
C:\>cd tmp  
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");  
puts("[+] Trojan-Dropper.Win32.Demp.rft PWNED!");  
puts("[+] MD5: db01783710e0c5aff92156a0e76deade");  
puts("[+] By Malvuln");  
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