This script is Copyright (C) 2013-2014 Tenable Network Security, Inc.
The remote Red Hat host is missing one or more security updates.
Updated kernel packages that fix two security issues and four bugs are
now available for Red Hat Enterprise Linux 5.6 Extended Update
The Red Hat Security Response Team has rated this update as having
moderate security impact. Common Vulnerability Scoring System (CVSS)
base scores, which give detailed severity ratings, are available for
each vulnerability from the CVE links in the References section.
The kernel packages contain the Linux kernel, the core of any Linux
This update fixes the following security issues :
* The way IPv4 and IPv6 protocol sequence numbers and fragment IDs
were generated could allow a man-in-the-middle attacker to inject
packets and possibly hijack connections. Protocol sequence numbers and
fragment IDs are now more random. (CVE-2011-3188, Moderate)
* A flaw was found in the Linux kernel's clock implementation on
32-bit, SMP (symmetric multiprocessing) systems. A local, unprivileged
user could use this flaw to cause a divide error fault, resulting in a
denial of service. (CVE-2011-3209, Moderate)
Red Hat would like to thank Dan Kaminsky for reporting CVE-2011-3188,
and Yasuaki Ishimatsu for reporting CVE-2011-3209.
In addition, this update fixes the following bugs :
* When the Global File System 2 (GFS2) file system is suspended, its
delete work queue is also suspended, along with any pending work on
the queue. Prior to this update, if GFS2's transaction lock was
demoted while the delete work queue was suspended, a deadlock could
occur on the file system because the file system tried to flush the
work queue in the lock demotion code. With this update, the delete
work queue is no longer flushed by the lock demotion code, and a
deadlock no longer occurs. Instead, the work queue is flushed by the
unmount operation, so that pending work is properly completed.
* A previously applied patch introduced a regression for third-party
file systems that do not set the FS_HAS_IODONE2 flag, specifically,
Oracle Cluster File System 2 (OCFS2). The patch removed a call to the
aio_complete function, resulting in no completion events being
processed, causing user-space applications to become unresponsive.
This update reintroduces the aio_complete function call, fixing this
* Certain devices support multiple operation modes. For example, EMC
CLARiiON disk arrays support ALUA mode and their own vendor specific
mode for failover. In Red Hat Enterprise Linux 5.5, a bug was
discovered that prevented tools such as multipath from being able to
select the device/hardware handler plug-in to use. This resulted in
the application (for example, multipath) not working properly. With
this update, the kernel has been modified to allow applications to
select the device/hardware handler to use, thus resolving this issue.
* This update improves the performance of delete/unlink operations in
a GFS2 file system with large files by adding a layer of metadata
read-ahead for indirect blocks. (BZ#743805)
Users should upgrade to these updated packages, which contain
backported patches to resolve these issues. The system must be
rebooted for this update to take effect.
See also :
Update the affected packages.
Risk factor :
Medium / CVSS Base Score : 6.8
CVSS Temporal Score : 5.9
Public Exploit Available : true