Brocade Security Advisory
An authenticated client can do the 'three way handshake' (P_HARD_RESET, P_HARD_RESET, P_CONTROL), where the P_CONTROL packet is the first that is allowed to carry payload. If that payload is too big, the OpenVPN server process will stop running due to an ASSERT() exception. That is also the reason why servers using tls-auth/tls-crypt are protected against this attack - the P_CONTROL packet is only accepted if it contains the session ID we specified, with a valid HMAC (challenge-response). This affects OpenVPN 2.3.12 and newer. OpenVPN versions 2.3.15, 2.4.2 and later include these fixes.
Products Confirmed Not Vulnerable
Brocade Fabric OS, Brocade FastIron OS, Brocade NetIron OS, Brocade Network OS, Brocade ServerIron ADX, Brocade Services Director, Brocade SLX-OS, and Brocade Virtual ADX, Brocade Virtual Traffic Manager, and Brocade Virtual Web Application Firewall are confirmed not affected by this vulnerability.
There are no workarounds that address this vulnerability.
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