Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/9fff4c02274c0162880844f27ff91407.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Trojan.Win32.NanoBot.onh Vulnerability: Insecure Permissions Description: NanoBot.onh creates an insecure dir named "AppData" under c:\ drive and grants change (C) permissions to the authenticated user group. Standard users can rename the executables 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. In this case the dropped file "amsiproxy.bat" is actually an PE32 executable as indicated by the presence of MZ header field and binary data. Type: PE32 MD5: 9fff4c02274c0162880844f27ff91407 Vuln ID: MVID-2021-0173 Dropped files: amsiproxy.bat (PE32) Disclosure: 04/17/2021 Exploit/PoC: C:\>cacls AppData C:\AppData 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:\AppData\Register-CimProvider>dir Volume in drive C has no label. Directory of C:\AppData\Register-CimProvider 04/15/2021 10:50 PM 1,101,316 amsiproxy.bat 1 File(s) 1,101,316 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).