CVE-2016-5389: linux kernel - challange ack information leak.

[Wade Mealing <wmealing () redhat com>]

Gday,

Red Hat Product Security has been made aware of an important issue in
the Linux kernel's implementation of challenge ACKS as specified in
RFC 5961. An attacker which knows a connections client IP, server IP
and server port can abuse the challenge ACK mechanism
to determine the accuracy of a normally 'blind' attack on the client or server.

Successful exploitation of this flaw could allow a remote attacker to
inject or control a TCP stream contents in a connection between a
Linux device and its connected client/server.

* This does NOT mean that cryptographic information is exposed.
* This is not a Man in the Middle (MITM) attack.

This was reported to Red Hat by Yue Cao, part of the Cyber Security
Group in the University of California

Thanks,

Wade Mealing
Red Hat Product Security Team

Red Hat Bugzilla:

https://bugzilla.redhat.com/show_bug.cgi?id=1354708

Patch:

https://www.mail-archive.com/netdev () vger kernel org/msg118677.html