In an internal audit, ISC discovered multiple buffer overflow flaws in versions 3.0 through 3.0.1RC10 of its DHCP product, according to the CERT Co-ordination Center (CERT/CC).
The flaws lie in a feature of ISC's DHCP product that allows the DHCP server to update a Domain Name System (DNS) server automattically. An attacker could take over an affected system by sending a DHCP message containing a large host name.
The ISC DHCP software ships as part of products from Red Hat and SuSE Linux, but the vulnerability status of many other vendors is still unknown. Red Hat already has a patch available, while SuSE is working on a software update.
DHCP software is used to assign users Internet Protocol (IP) addresses automatically 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 (Berkeley Internet Name Domain) DNS software, has released an update fixing the DHCP flaws. CERT maintains a list of suppliers whose software could contain the ISC software and may also be vulnerable.
The CERT advisory is at: www.cert.org/advisories/CA-2003-01.html