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ipsec -- reply attack vulnerability


Problem Description

IPsec provides an anti-replay service which when enabled prevents an attacker from successfully executing a replay attack. This is done through the verification of sequence numbers. A programming error in the fast_ipsec(4) implementation results in the sequence number associated with a Security Association not being updated, allowing packets to unconditionally pass sequence number verification checks.


An attacker able to to intercept IPSec packets can replay them. If higher level protocols which do not provide any protection against packet replays (e.g., UDP) are used, this may have a variety of effects.


No workaround is available.



portaudit: ipsec -- reply attack vulnerability

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If you have found a vulnerability in a FreeBSD port not listed in the database, please contact the FreeBSD Security Officer. Refer to "FreeBSD Security Information" for more information.

Oliver Eikemeier <>