RHSA-2016:1632 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

It was found that the RFC 5961 challenge ACK rate limiting as implemented
in the Linux kernel's networking subsystem allowed an off-path attacker to
leak certain information about a given connection by creating congestion on
the global challenge ACK rate limit counter and then measuring the changes
by probing packets. An off-path attacker could use this flaw to either
terminate TCP connection and/or inject payload into non-secured TCP
connection between two endpoints on the network. (CVE-2016-5696, Important)

Red Hat would like to thank Yue Cao from Cyber Security Group in the CS
department of University of California, Riverside, for reporting this issue.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 7 x86_64
• Red Hat Enterprise Linux for Real Time for x86_64 - Extended Life Cycle Support 7 x86_64

Fixes

• BZ - 1354708 - CVE-2016-5696 kernel: challenge ACK counter information disclosure.

CVEs

• CVE-2016-5696

References

• http://www.redhat.com/security/updates/classification/#normal