RHEL 2.1 / 3 : krb5 (RHSA-2004:236)
Critical Nessus Plugin ID 12502
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionUpdated Kerberos 5 (krb5) packages which correct buffer overflows in the krb5_aname_to_localname function are now available.
Kerberos is a network authentication system.
Bugs have been fixed in the krb5_aname_to_localname library function.
Specifically, buffer overflows were possible for all Kerberos versions up to and including 1.3.3. The krb5_aname_to_localname function translates a Kerberos principal name to a local account name, typically a UNIX username. This function is frequently used when performing authorization checks.
If configured with mappings from particular Kerberos principals to particular UNIX user names, certain functions called by krb5_aname_to_localname will not properly check the lengths of buffers used to store portions of the principal name. If configured to map principals to user names using rules, krb5_aname_to_localname would consistently write one byte past the end of a buffer allocated from the heap. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2004-0523 to this issue.
Only configurations which enable the explicit mapping or rules-based mapping functionality of krb5_aname_to_localname() are vulnerable.
These configurations are not the default.
Users of Kerberos are advised to upgrade to these erratum packages which contain backported security patches to correct these issues.
SolutionUpdate the affected packages.