Packed.Win32.Katusha.o Insecure Permissions

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/e184abe44bec183a522d2c66bc3f90e0.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Packed.Win32.Katusha.o (Ransomeware)  
Vulnerability: Insecure Permissions EoP  
Description: The malware create two dirs, one of them under the users home dir. The files dropped are hidden and can be viewed using dir /a command. Then after about 35 secs locks the victims screen, issuing a warning about pirated software and to pay in BTC. If not paid, a warrant will be issued for arrest. However, the malware grants full (F) permissions to everyone for the "bkkYoIYg" dir under that targets users home dir.  
  
C:\>cacls C:\Users\VICTIM\bkkYoIYg\BkkMEYcs.exe  
C:\Users\VICTIM\bkkYoIYg\BkkMEYcs.exe No permissions are set. All user have full control  
  
Type: PE32  
MD5: e184abe44bec183a522d2c66bc3f90e0  
Vuln ID: MVID-2021-0061  
Dropped files: BkkMEYcs.exe, BkkMEYcs, BkkMEYcs.inf, C:\ProgramData\HcgIwoAM\DiAYIoQI.exe, DiAYIoQI.inf  
Disclosure: 01/28/2021  
  
  
Exploit/PoC:  
1) switch user to standard user for PoC  
2) open taskmgr kill the malware  
3) now you are able to place any files under the vuln "bkkYoIYg" dir under the privileged users home dir.  
  
  
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).  
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