CERT warns of DHCP vulnerabilities

Several potentially serious security flaws exist in the Internet Software Consortium’s Dynamic Host Configuration Protocol software, which is shipped as part of several operating systems, the CERT Coordination Center warned Thursday.

In an internal audit, ISC discovered multiple buffer overflow flaws in Versions 3.0 through 3.0.1RC10 of its DHCP product, according to a CERT advisory.

The flaws lie in a feature of ISC’s DHCP product that allows the DHCP server to automatically update a DNS server. An attacker could take over an affected system by sending a DHCP message containing a large hostname, according to CERT.

The ISC DHCP software ships as part of products from Red Hat and SuSE Linux AG; the vulnerability status of many other vendors is still unknown, CERT said. Red Hat already has a patch available; SuSE is working on a software update, according to CERT.

DHCP software is used to automatically assign users IP addresses when they sign on to a network. Typically a DHCP server is not accessible externally, limiting the threat of attacks.

ISC, which also provides the widely used BIND DNS software, has released an update fixing the DHCP flaws. CERT maintains a list of vendors whose software could contain the ISC software and may also be vulnerable.

The CERT advisory is at: http://www.cert.org/advisories/CA-2003-01.html