Vulnerability identifier: #VU6662
Vulnerability risk: Medium
CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID:
CWE-ID:
CWE-113
Exploitation vector: Network
Exploit availability: No
Vulnerable software:
OpenVPN Access Server
Server applications /
Remote access servers, VPN
Vendor: OpenVPN
Description
The vulnerability allows a remote attacker to inject arbitrary session cookies and gain control over victim's VPN session.
The vulnerability exists due to insufficient sanitization of user-supplied data (e.g. %0A character), passed via URL. A remote attacker can create a specially crafted link, trick the victim into following it and spoof HTTP headers, used by OpenVPN Access Server to authenticate users.
Successful exploitation of the vulnerability may allow an attacker to inject arbitrary cookie values, including session identifier, and gain full access to victim's session.
Exploitation example for injecting victim's session identifier, controlled by the attacker:
https://[host]/__session_start__/%0aSet-Cookie: openvpn_sess_******=******cf23; Path=/; Secure; HttpOnly
Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.
Vulnerable software versions
OpenVPN Access Server: 2.1.0 - 2.1.4
External links
https://seclists.org/oss-sec/2017/q2/332
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.