SB2017052401 - CRLF injection in OpenVPN Access Server

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Main Vulnerability Database SB2017052401

SB2017052401 - CRLF injection in OpenVPN Access Server

Published: May 24, 2017

Security Bulletin ID SB2017052401
Severity
Medium
Patch available
NO
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) CRLF injection (CVE-ID: CVE-2017-5868)

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

Remediation

Cybersecurity Help is not aware of any official remediation provided by the vendor.

References