Switch branches/tags
Nothing to show
Find file History
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


BestXsoftware Best Free Keylogger 5.2.9 Privilege Escalation

  • Author: Martino Sani
  • Release date: 2018-10-19
  • Software: https://bestxsoftware.com/
  • Version: 5.2.9 and probably previous versions
  • CVE: CVE-2018-18519


BestXsoftware Best Free Keylogger 5.2.9 allows local users to gain privileges via a Trojan horse %PROGRAMFILES%\BFK 5.2.9\syscrb.exe file because of insecure permissions for the BUILTIN\Users group.

Attack Vectors

Best Free Keylogger v. 5.2.9 is installed on the system.

The attacker (with arbitrary privileges) replaces the file C:\Program Files\BFK 5.2.9\syscrb.exe. It is world writable (Windows Group: Users).

A victim user opens a session, such as through a RDP client, and C:\Program Files\BFK 5.2.9\syscrb.exe is executed with the logged-in user's privileges.

The attacker can execute arbitrary code impersonating the victim.


  • 2018-09-28: Vendor notification. No response.
  • 2018-10-10: No responses from the vendor. Disclosure.

The author is not responsible for the misuse of the information provided in this advisory.