Scientific Linux Security Update : kernel on SL5.x i386/x86_64 (Dirty COW)

High Nessus Plugin ID 94432


The remote Scientific Linux host is missing one or more security updates.


Security Fix(es) :

- A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged, local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system.
(CVE-2016-5195, Important)

- It was found that stacking a file system over procfs in the Linux kernel could lead to a kernel stack overflow due to deep nesting, as demonstrated by mounting ecryptfs over procfs and creating a recursion by mapping /proc/environ. An unprivileged, local user could potentially use this flaw to escalate their privileges on the system. (CVE-2016-1583, Important)

Bug Fix(es) :

- In some cases, a kernel crash or file system corruption occurred when running journal mode 'ordered'. The kernel crash was caused by a NULL pointer dereference due to a race condition between two journal functions. The file system corruption occurred due to a race condition between the do_get_write_access() function and buffer writeout. This update fixes both race conditions. As a result, neither the kernel crash, nor the file system corruption now occur.

- Prior to this update, some Global File System 2 (GFS2) files had incorrect time stamp values due to two problems with handling time stamps of such files. The first problem concerned the atime time stamp, which ended up with an arbitrary value ahead of the actual value, when a GFS2 file was accessed. The second problem was related to the mtime and ctime time stamp updates, which got lost when a GFS2 file was written to from one node and read from or written to from another node. With this update, a set of patches has been applied that fix these problems. As a result, the time stamps of GFS2 files are now handled correctly.


Update the affected packages.

See Also

Plugin Details

Severity: High

ID: 94432

File Name: sl_20161028_kernel_on_SL5_x.nasl

Version: $Revision: 2.6 $

Type: local

Agent: unix

Published: 2016/10/31

Modified: 2017/01/16

Dependencies: 12634

Risk Information

Risk Factor: High


Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C


Base Score: 7.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: x-cpe:/o:fermilab:scientific_linux

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/RedHat/release, Host/RedHat/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2016/10/28

Exploitable With


Core Impact

Reference Information

CVE: CVE-2016-1583, CVE-2016-5195

IAVA: 2016-A-0306