FreeBSD Security Advisory FreeBSD-SA-05:15 - Two problems have been discovered in the FreeBSD TCP stack. First, when a TCP packets containing a timestamp is received, inadequate checking of sequence numbers is performed, allowing an attacker to artificially increase the internal "recent" timestamp for a connection. Second, a TCP packet with the SYN flag set is accepted for established connections, allowing an attacker to overwrite certain TCP options.
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