The Dynamic Host Configuration Protocol (DHCP) server is used to configure clients that dynamically connect to a network (WLAN hotspots, customer networks, ...). The CERT informed us about a buffer overflow in the logging code of the server that can be triggered by a malicious client by supplying multiple hostnames. The hostname strings are concatenated and copied in a fixed size buffer without checking the buffer bounds. Other possible buffer overflow conditions exist in using vsprintf() instead of vsnprintf(). This behavior can be configured during compiletime. The dhcp/dhcp-server package coming with SUSE Linux used the vulnerable vsprintf() function.
Since SUSE Linux 8.1/SUSE Linux Enterprise Server 8 the DHCP server runs as non-root user in a chroot jail. This setup limits the impact of a successful attack.
There is no temporary workaround known.
Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement. Then, install the package using the command "rpm -Fhv file.rpm" to apply the update. Our maintenance customers are being notified individually. The packages are being offered to install from the maintenance web.
With Rapid7 live dashboards, I have a clear view of all the assets on my network, which ones can be exploited, and what I need to do in order to reduce the risk in my environment in real-time. No other tool gives us that kind of value and insight.
– Scott Cheney, Manager of Information Security, Sierra View Medical Center