RHEL 6 : kernel (RHSA-2015:1623)

critical Nessus Plugin ID 85396

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Synopsis

The remote Red Hat host is missing one or more security updates for kernel.

Description

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2015:1623 advisory.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Two flaws were found in the way the Linux kernel's networking implementation handled UDP packets with incorrect checksum values. A remote attacker could potentially use these flaws to trigger an infinite loop in the kernel, resulting in a denial of service on the system, or cause a denial of service in applications using the edge triggered epoll functionality. (CVE-2015-5364, CVE-2015-5366, Important)

This update also fixes the following bugs:

* When removing a directory, and a reference was held to that directory by a reference to a negative child dentry, the directory dentry was previously not killed. In addition, once the negative child dentry was killed, an unlinked and unused dentry was present in the cache. As a consequence, deadlock could be caused by forcing the dentry eviction while the file system in question was frozen. With this update, all unused dentries are unhashed and evicted just after a successful directory removal, which avoids the deadlock, and the system no longer hangs in the aforementioned scenario. (BZ#1243400)

* Due to the broken s_umount lock ordering, a race condition occurred when an unlinked file was closed and the sync (or syncfs) utility was run at the same time. As a consequence, deadlock occurred on a frozen file system between sync and a process trying to unfreeze the file system. With this update, sync (or syncfs) is skipped on a frozen file system, and deadlock no longer occurs in the aforementioned situation. (BZ#1243404)

* Previously, in the scenario when a file was opened by file handle (fhandle) with its dentry not present in dcache (cold dcache) and then making use of the unlink() and close() functions, the inode was not freed upon the close() system call. As a consequence, the iput() final was delayed indefinitely. A patch has been provided to fix this bug, and the inode is now freed as expected. (BZ#1243406)

* Due to a corrupted Executable and Linkable Format (ELF) header in the /proc/vmcore file, the kdump utility failed to provide any information.
The underlying source code has been patched, and kdump now provides debuging information for kernel crashes as intended. (BZ#1245195)

* Previously, running the multipath request queue caused regressions in cases where paths failed regularly under I/O load. This regression manifested as I/O stalls that exceeded 300 seconds. This update reverts the changes aimed to reduce running the multipath request queue resulting in I/O completing in a timely manner. (BZ#1246095)

All kernel users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL kernel package based on the guidance in RHSA-2015:1623.

Plugin Details

Severity: Critical

ID: 85396

File Name: redhat-RHSA-2015-1623.nasl

Version: 2.16

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 8/14/2015

Updated: 11/4/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2015-5364

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS Score Source: CVE-2015-5366

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel, p-cpe:/a:redhat:enterprise_linux:kernel-headers, p-cpe:/a:redhat:enterprise_linux:kernel-firmware, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-kdump, p-cpe:/a:redhat:enterprise_linux:kernel-bootwrapper, p-cpe:/a:redhat:enterprise_linux:python-perf, p-cpe:/a:redhat:enterprise_linux:kernel-kdump-devel, p-cpe:/a:redhat:enterprise_linux:kernel-devel, p-cpe:/a:redhat:enterprise_linux:kernel-debug, p-cpe:/a:redhat:enterprise_linux:perf

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/4/2015

Vulnerability Publication Date: 8/31/2015

Reference Information

CVE: CVE-2015-5364, CVE-2015-5366

CWE: 835

RHSA: 2015:1623

Detections

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