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Old 5th November 2014
J65nko J65nko is offline
Join Date: May 2008
Location: Budel - the Netherlands
Posts: 3,588
Default FreeBSD-Security Advisory for SSHD


II. Problem Description

Although OpenSSH is not multithreaded, when OpenSSH is compiled with
Kerberos support, the Heimdal libraries bring in the POSIX thread
library as a dependency. Due to incorrect library ordering while
linking sshd(8), symbols in the C library which are shadowed by the
POSIX thread library may not be resolved correctly at run time.

Note that this problem is specific to the FreeBSD build system and
does not affect other operating systems or the version of OpenSSH
available from the FreeBSD ports tree.

III. Impact

An incorrectly linked sshd(8) child process may deadlock while
handling an incoming connection. The connection may then time out or
be interrupted by the client, leaving the deadlocked sshd(8) child
process behind. Eventually, the sshd(8) parent process stops
accepting new connections.

An attacker may take advantage of this by repeatedly connecting and
then dropping the connection after having begun, but not completed,
the authentication process.
You don't need to be a genius to debug a pf.conf firewall ruleset, you just need the guts to run tcpdump
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