Local Privilege Escalation via Weak Service Binary Permissions

Vulnerability Description

Attackers with local access to the medical office computer can escalate their Windows user privileges to "NT AUTHORITY\SYSTEM" by overwriting one of two Elefant service binaries with weak permissions. The default installation directory of Elefant is "C:\Elefant1" which is writable for all users. In addition, the Elefant installer registers two Firebird database services which are running as “NT AUTHORITY\SYSTEM”.  Path: C:\Elefant1\Firebird_2\bin\fbserver.exe Path: C:\Elefant1\Firebird_2\bin\fbguard.exe Both service binaries are user writable. This means that a local attacker can rename one of the service binaries, replace the service executable with a new executable, and then restart the system. Once the system has rebooted, the new service binary is executed as "NT AUTHORITY\SYSTEM".

References

• https://r.sec-consult.com/hasomed
• https://hasomed.de/produkte/elefant/