Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/de613b96174056ef22b42e112d0e61a5.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Trojan-Spy.Win32.KeyLogger.qt Vulnerability: Insecure Permissions Description: KeyLogger.qt creates a hidden insecure dir named "config" under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename "rundll32.exe" dropped by the keylogger to disable it or replace with their own executable. Then wait for a privileged user to logon to the infected machine to potentially escalate privileges. Type: PE32 MD5: de613b96174056ef22b42e112d0e61a5 Vuln ID: MVID-2021-0124 Dropped files: rundll32.exe Disclosure: 03/10/2021 Exploit/PoC: #include "windows.h" void main(void){ system("attrib -s -h C:\\config\\rundll32.exe"); system("rename C:\\config\\rundll32.exe 13"); Sleep(1000); puts("[+] Disabled by renaming C:\\config\\rundll32.exe to 13 ...\n"); Sleep(1000); puts("[+] Trojan-Spy.Win32.KeyLogger.qt PWNED!"); puts("[+] MD5: de613b96174056ef22b42e112d0e61a5"); puts("[+] By Malvuln"); system("pause"); } C:\config>cacls \config C:\config 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:\config>dir Volume in drive C has no label. Directory of C:\config File Not Found C:\config>dir /a Volume in drive C has no label. Directory of C:\config 06/16/2012 12:54 AM 585,778 rundll32.exe 1 File(s) 585,778 bytes 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).