A time-of-check time-of-use vulnerability in PulseSecureService.exe in Pulse Secure Client versions prior to 9.1.6 down to 5.3 R70 for Windows (which runs as NT AUTHORITY/SYSTEM) allows unprivileged users to run a Microsoft Installer executable with elevated privileges.
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state.
| Link | Tags |
|---|---|
| https://kb.pulsesecure.net/?atype=sa | vendor advisory |
| https://twitter.com/sepcali/status/1262551597990711296 | third party advisory |
| http://seclists.org/fulldisclosure/2020/Jun/25 | third party advisory mailing list |
| https://www.redtimmy.com/privilege-escalation/pulse-secure-client-for-windows-9-1-6-toctou-privilege-escalation-cve-2020-13162/ | third party advisory exploit |
| http://packetstormsecurity.com/files/158117/Pulse-Secure-Client-For-Windows-Local-Privilege-Escalation.html | third party advisory vdb entry |
| https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44503 | vendor advisory |
| https://twitter.com/gsepcali/status/1262551597990711296 | third party advisory |
| https://twitter.com/gsepcali/status/1272927080909623297 | third party advisory |
| http://seclists.org/fulldisclosure/2020/Sep/15 | third party advisory mailing list |
| http://packetstormsecurity.com/files/159065/Pulse-Secure-Windows-Client-Privilege-Escalation.html | third party advisory vdb entry |