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Scientific Linux Security Update : dnsmasq on SL6.x i386/x86_64 (20130221)
medium Nessus Plugin ID 64950
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Synopsis
The remote Scientific Linux host is missing one or more security updates.Description
It was discovered that dnsmasq, when used in combination with certain libvirtd configurations, could incorrectly process network packets from network interfaces that were intended to be prohibited. A remote, unauthenticated attacker could exploit this flaw to cause a denial of service via DNS amplification attacks. (CVE-2012-3411)In order to fully address this issue, libvirt package users are advised to install updated libvirt packages.
This update also fixes the following bug :
- Due to a regression, the lease change script was disabled. Consequently, the 'dhcp-script' option in the /etc/dnsmasq.conf configuration file did not work. This update corrects the problem and the 'dhcp-script' option now works as expected.
This update also adds the following enhancements :
- Prior to this update, dnsmasq did not validate that the tftp directory given actually existed and was a directory. Consequently, configuration errors were not immediately reported on startup. This update improves the code to validate the tftp root directory option. As a result, fault finding is simplified especially when dnsmasq is called by external processes such as libvirt.
- The dnsmasq init script used an incorrect Process Identifier (PID) in the 'stop', 'restart', and 'condrestart' commands. Consequently, if there were some dnsmasq instances running besides the system one started by the init script, then repeated calling of 'service dnsmasq' with 'stop' or 'restart' would kill all running dnsmasq instances, including ones not started with the init script. The dnsmasq init script code has been corrected to obtain the correct PID when calling the 'stop', 'restart', and 'condrestart' commands. As a result, if there are dnsmasq instances running in addition to the system one started by the init script, then by calling 'service dnsmasq' with 'stop' or 'restart' only the system one is stopped or restarted.
- When two or more dnsmasq processes were running with DHCP enabled on one interface, DHCP RELEASE packets were sometimes lost. Consequently, when two or more dnsmasq processes were running with DHCP enabled on one interface, releasing IP addresses sometimes failed. This update sets the SO_BINDTODEVICE socket option on DHCP sockets if running dnsmasq with DHCP enabled on one interface. As a result, when two or more dnsmasq processes are running with DHCP enabled on one interface, they can release IP addresses as expected.
Solution
Update the affected dnsmasq, dnsmasq-debuginfo and / or dnsmasq-utils packages.See Also
Plugin Details
Severity: Medium
ID: 64950
File Name: sl_20130221_dnsmasq_on_SL6_x.nasl
Version: 1.6
Type: local
Agent: unix
Published: 3/1/2013
Updated: 1/14/2021
Supported Sensors: Nessus Agent, Nessus
Risk Information
VPR
Risk Factor: Low
Score: 3.6
CVSS v2
Risk Factor: Medium
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Vulnerability Information
CPE: p-cpe:/a:fermilab:scientific_linux:dnsmasq, p-cpe:/a:fermilab:scientific_linux:dnsmasq-debuginfo, p-cpe:/a:fermilab:scientific_linux:dnsmasq-utils, x-cpe:/o:fermilab:scientific_linux
Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu
Patch Publication Date: 2/21/2013
Vulnerability Publication Date: 3/5/2013
Reference Information
CVE: CVE-2012-3411