Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/ee22eea131c0e00162e4ba370f396a00.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Trojan.Win32.Pluder.o Vulnerability: Insecure Permissions Description: Creates an insecure dir named "z_Drivers" under c:\ drive, granting change (C) permissions to authenticated user group. Pluder.o also creates several registry key entries under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run for persistence. Standard users can rename the malware and reboot to disable it or replace it with their own executable to escalate privileges when a privileged user logs on. When renaming the malware it checks the dir and creates a new "svchost.exe" each time so we need to take additional step to create our own fake one in order to disable it. To successfully rename the malware we have to call Windows "attrib -h" command to unhide the executable or the rename will fail. Type: PE32 MD5: ee22eea131c0e00162e4ba370f396a00 Vuln ID: MVID-2021-0103 Dropped files: svchost.exe Disclosure: 02/21/2021 Exploit/PoC: #include "stdio.h" #include "windows.h" void main(void){ system("attrib -h C:\\z_Drivers\\svchost.exe"); puts("Unhiding the malware to rename it..."); system("RENAME C:\\z_Drivers\\svchost.exe 13"); system("DEL /F C:\\z_Drivers\\svchost.exe"); system("echo > C:\\z_Drivers\\svchost.exe"); Sleep(1000); puts("[+] Disabled persistence by renaming the malware to 13 ...\n"); puts("Created fake svchost.exe to prevent recreation"); puts("Restart your computer ..."); puts("[+] Trojan.Win32.Pluder.o PWNED!\n"); puts("[+] MD5: ee22eea131c0e00162e4ba370f396a00\n"); puts("[+] By Malvuln\n"); system("pause"); } C:\>cacls \z_Drivers C:\z_Drivers 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 \z_Drivers Volume in drive C has no label. Directory of C:\z_Drivers .. 12/30/2019 03:58 AM 255,488 svchost.exe 1 File(s) 255,488 bytes 2 Dir(s) 49,774,018,560 bytes free 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).