+++ This bug was initially created as a clone of Bug #157103 +++ The MIT krb5 Key Distribution Center (KDC) implementation can corrupt the heap by attempting to free memory at a random address when it receives a certain unlikely (but valid) request via a TCP connection. This attempt to free unallocated memory can result in a KDC crash and consequent denial of service. [CAN-2005-1174] Additionally, the same request, when received by the KDC via either TCP or UDP, can trigger a bug in the krb5 library which results in a single-byte overflow of a heap buffer. Additionally, application servers are vulnerable to a highly improbable attack, provided that the attacker controls a realm sharing a cross-realm key with the target realm. [CAN-2005-1175] An unauthenticated attacker may be able to use these vulnerabilities to execute arbitrary code on the KDC host, potentially compromising an entire Kerberos realm. No exploit code is known to exist at this time. Exploitation of these vulnerabilities is believed to be difficult.
FC4 will be out before the embargo on this issue is lifted, we'll have to keep that in mind.
According to MIT, in order to exploit CAN-2005-1175 the attacker must control a realm sharing a cross-realm key with the target realm. I'm lowering the severity to "moderate" for that particular issue.
public at http://web.mit.edu/kerberos/www/advisories/ removing embargo
This report targets the FC3 or FC4 products, which have now been EOL'd. Could you please check that it still applies to a current Fedora release, and either update the target product or close it ? Thanks.
Issue was fixed in upstream version 1.4.2. All current Fedora versions ship version 1.6+. Closing.