RHEL 5 : dnsmasq (RHSA-2009:1238)
Medium Nessus Plugin ID 40834
SynopsisThe remote Red Hat host is missing a security update.
DescriptionAn 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 Red Hat Security Response Team.
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.
SolutionUpdate the affected dnsmasq package.