Synopsis
The remote service is affected by an information disclosure vulnerability.
Description
Based on its response to a TLS request with a specially crafted heartbeat message (RFC 6520), the remote OpenVPN service appears to be affected by an out-of-bounds read flaw.
Because the remote OpenVPN service does not employ the 'HMAC Firewall' feature, this vulnerability can be exploited without authentication.
This vulnerability could allow an attacker to obtain secret keys, cleartext VPN traffic, and other sensitive data.
Solution
Upgrade the version of OpenSSL that OpenVPN is linked against to 1.0.1g or later. Alternatively, recompile OpenSSL with the '-DOPENSSL_NO_HEARTBEATS' flag to disable the vulnerable functionality. For Windows servers, upgrade to OpenVPN version 2.3.2-I004 or later.