FreeBSD : krb5 -- multiple checksum handling vulnerabilities (11bbccbc-03ee-11e0-bcdb-001fc61c2a55)
Low Nessus Plugin ID 51101
SynopsisThe remote FreeBSD host is missing one or more security-related updates.
DescriptionThe MIT Kerberos team reports :
MIT krb5 clients incorrectly accept an unkeyed checksums in the SAM-2 preauthentication challenge.
An unauthenticated remote attacker could alter a SAM-2 challenge, affecting the prompt text seen by the user or the kind of response sent to the KDC. Under some circumstances, this can negate the incremental security benefit of using a single-use authentication mechanism token.
MIT krb5 incorrectly accepts RFC 3961 key-derivation checksums using RC4 keys when verifying KRB-SAFE messages.
An unauthenticated remote attacker has a 1/256 chance of forging KRB-SAFE messages in an application protocol if the targeted pre-existing session uses an RC4 session key. Few application protocols use KRB-SAFE messages.
SolutionUpdate the affected packages.