Untrusted search path in PureVPN - CVE-2018-7484

Detailed vulnerability description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

An issue was discovered in PureVPN through 5.19.4.0 on Windows. The client installation grants the Everyone group Full Control permission to the installation directory. In addition, the PureVPNService.exe service, which runs under NT AuthoritySYSTEM privileges, tries to load several dynamic-link libraries using relative paths instead of the absolute path. When not using a fully qualified path, the application will first try to load the library from the directory from which the application is started. As the residing directory of PureVPNService.exe is writable to all users, this makes the application susceptible to privilege escalation through DLL hijacking.

How to mitigate CVE-2018-7484

Sources

• http://www.defensecode.com/advisories/DC-2018-02-001-PureVPN-Windows-Privilege-Escalation.pdf
• https://www.securityfocus.com/archive/1/541803