| A number of vulnerabilities were discovered in OpenVPN that were fixed in
the 2.0.1 release:
A DoS attack against the server when run with "verb 0" and without
"tls-auth" when a client connection to the server fails certificate
verification, the OpenSSL error queue is not properly flushed. This could
result in another unrelated client instance on the server seeing the error
and responding to it, resulting in a disconnection of the unrelated client.
A DoS attack against the server by an authenticated client that sends a
packet which fails to decrypt on the server, the OpenSSL error queue was
not properly flushed. This could result in another unrelated client
instance on the server seeing the error and responding to it, resulting in
a disconnection of the unrelated client.
A DoS attack against the server by an authenticated client is possible in
"dev tap" ethernet bridging mode where a malicious client could
theoretically flood the server with packets appearing to come from hundreds
of thousands of different MAC addresses, resulting in the OpenVPN process
exhausting system virtual memory.
If two or more client machines tried to connect to the server at the same
time via TCP, using the same client certificate, a race condition could
crash the server if --duplicate-cn is not enabled on the server. | 