Security vulnerability in ISC DHCPD
ISC DHCPD in its version 3 introduced new dns-update features. ISC DHCPD is vulnerable to a format string bug attack, while reporting the result of a dns-update request. Since ISC DHCPD runs with root privileges, attackers can use this bug to gain unauthorized access, to the system running ISC DHCPD, as root user.
ISC DHCPDv3 Remote Root Compromise
CERT Advisory CA-2002-12 Format String Vulnerability in ISC DHCPD
Internet Software Consortium released a patch which is added to the CERT Security advisory linked above. Also, version 3.0p1 of the ISC DHCP Distribution has been released and is available on the ISC web site.
Update (10 May 2002) - Conectiva released a Security Advisory (CLA-2002:483) that deals with this issue. It can be read on the following link:
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CERT's quick workaround - "As a temporary measure, it may be possible to limit the scope of this vulnerability by blocking access to DHCP services at the network perimeter".