ISC see a little silhouetto of a DHCP flaw
Thunderbolt and lightning - not so very frightening
Multiple buffer overflow vulnerabilities in the Internet Software Consortium (ISC) implementation of the Dynamic Host Configuration Protocol (DHCP) have come to light.
An advisory by security clearing house CERT on Wednesday night warns the flaws (in common with buffer overflow bugs in general) might allow remote attackers to execute arbitrary code on affected systems. It's not believed that the flaws have been coded up into s'kiddie-friendly exploits, and the majority of systems based on ISC DHCPD omit the flawed component. That includes the ISC's popular BIND implementation, since you ask.
So the problem is not as bad as it might otherwise have been, and there is a fix.
The root cause of the problem, such as it is, is within the error handling routines of the minires library, which is used by NSUPDATE (a feature that supports for dynamic DNS updates) to resolve hostnames.
During an internal source code audit, developers from the ISC discovered several stack-based buffer overflows that may be exploitable (because of the flaw) by sending a DHCP message containing a large hostname value.
Admins are encouraged to review CERT's advisory, which provides links to vendor-supplied patches, to see if any of the products they use are affected.
For example, Red Hat distributes a vulnerable version of ISC DHCP in Red Hat Linux 8.0 but has released an update tool here designed to address the problem.
The Internet Software Consortium itself has also supplied updates. A patched version of ISC DHCP 3.0 (3.0pl2) and a new release candidate for the next bug-fix release (3.0.1RC11) are both available form here. ®
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