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Red Hat: RHSA-2009:1238-01 Critical TFTP Exploits in dnsmasq

red hat
Calendar Grey August 31, 2009
Dist Redhat Esm H88
The latest dnsmasq update addresses serious vulnerabilities impacting Red Hat Enterprise Linux 5.
An updated dnsmasq package that fixes two security issues is now available for Red Hat Enterprise Linux 5. This update has been rated as having important security impact by the Re...

Solution

Before applying this update, make sure that all previously-released errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at

Summary

Dnsmasq is a lightweight and easy to configure DNS forwarder and DHCP server.
Core Security Technologies discovered a heap overflow flaw in dnsmasq when the TFTP service is enabled (the "--enable-tftp" command line option, or by enabling "enable-tftp" in "/etc/dnsmasq.conf"). If the configured tftp-root is sufficiently long, and a remote user sends a request that sends a long file name, dnsmasq could crash or, possibly, execute arbitrary code with the privileges of the dnsmasq service (usually the unprivileged "nobody" user). (CVE-2009-2957)
A NULL pointer dereference flaw was discovered in dnsmasq when the TFTP service is enabled. This flaw could allow a malicious TFTP client to crash the dnsmasq service. (CVE-2009-2958)
Note: The default tftp-root is "/var/ftpd", which is short enough to make it difficult to exploit the CVE-2009-2957 issue; if a longer directory name is used, arbitrary code execution may be possible. As well, the dnsmasq package distributed by Red Hat does not have TFTP support enabled by default.
All users of dnsmasq should upgrade to this updated package, which contains a backported patch to correct these issues. After installing the updated package, the dnsmasq service must be restarted for the update to take effect.

Topics%20covered

Topics Covered

security advisory Red Hat important heap overflow NULL pointer dnsmasq TFTP

References

https://www.cve.org/CVERecord?id=CVE-2009-2957 https://www.cve.org/CVERecord?id=CVE-2009-2958 https://access.redhat.com/security/updates/classification#important

Package List

Red Hat Enterprise Linux Desktop (v. 5 client):
Source:
i386: dnsmasq-2.45-1.1.el5_3.i386.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.i386.rpm
x86_64: dnsmasq-2.45-1.1.el5_3.x86_64.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.x86_64.rpm
Red Hat Enterprise Linux (v. 5 server):
Source:
i386: dnsmasq-2.45-1.1.el5_3.i386.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.i386.rpm
ia64: dnsmasq-2.45-1.1.el5_3.ia64.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.ia64.rpm
ppc: dnsmasq-2.45-1.1.el5_3.ppc.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.ppc.rpm
s390x: dnsmasq-2.45-1.1.el5_3.s390x.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.s390x.rpm
x86_64: dnsmasq-2.45-1.1.el5_3.x86_64.rpm dnsmasq-debuginfo-2.45-1.1.el5_3.x86_64.rpm
These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key#package


Severity
important
Lowest
Low
Medium
High
Critical

Advisory ID: RHSA-2009:1238-01
Product: Red Hat Enterprise Linux
Advisory URL: https://access.redhat.com/errata/RHSA-2009:1238.html
Issue date: 2009-08-31

Topic

An updated dnsmasq package that fixes two security issues is now availablefor Red Hat Enterprise Linux 5.This update has been rated as having important security impact by the RedHat Security Response Team.

Topics%20covered

Topics Covered

security advisory Red Hat important heap overflow NULL pointer dnsmasq TFTP

Relevant Releases Architectures

Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64

Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64

Bugs Fixed

519020 - CVE-2009-2957, CVE-2009-2958 dnsmasq: multiple vulnerabilities in TFTP server

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