The spnego_gss_accept_sec_context function in lib/gssapi/spnego/spnego_mech.c in the SPNEGO GSS-API functionality in MIT Kerberos 5 (aka krb5) 1.7 before 1.7.2 and 1.8 before 1.8.1 allows remote attackers to cause a denial of service (assertion failure and daemon crash) via an invalid packet that triggers incorrect preparation of an error token.

Emmanuel Bouillon discovered that Kerberos did not correctly handle certain message types. An unauthenticated remote attacker could send specially crafted traffic to cause the KDC to crash, leading to a denial of service. (CVE-2010-0283)

Nalin Dahyabhai, Jan iankko Lieskovsky, and Zbysek Mraz discovered that Kerberos did not correctly handle certain GSS packets. An unauthenticated remote attacker could send specially crafted traffic that would cause services using GSS-API to crash, leading to a denial of service. (CVE-2010-0628).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

A GSSAPI-authenticated service could be remotely forced to trigger an assertion failure by sending it certain invalid messages (MITKRB5-SA-2010-002, CVE-2010-0628). The included patch for adding PAM support to the bundled FTP server contained a bug which would cause the service to crash if a client attempted to authenticate as a user who was not known to the server system. In the default xinetd configuration, the service would be invoked with the -a flag, and this would therefore only be possible if the client authenticated using GSSAPI beforehand.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Two vulnerabilities in krb5 can be used by remote attackers in denial of service attacks. The MIT security advisories report this as follows :

An unauthenticated remote attacker can send an invalid request to a KDC process that will cause it to crash due to an assertion failure, creating a denial of service.

An unauthenticated remote attacker could cause a GSS-API application, including the Kerberos administration daemon (kadmind) to crash.

MITKRB5-SA-2010-002: unauthenticated remote attacker could cause a GSS-API application including the Kerberos administration daemon (kadmind) to crash. CVE-2010-0628 has been assigned to this issue.

ID	Name	Product	Family	Severity
65122	Ubuntu 9.10 : krb5 vulnerabilities (USN-916-1)	Nessus	Ubuntu Local Security Checks	high
47369	Fedora 12 : krb5-1.7.1-6.fc12 (2010-4677)	Nessus	Fedora Local Security Checks	medium
47366	Fedora 13 : krb5-1.7.1-7.fc13 (2010-4608)	Nessus	Fedora Local Security Checks	medium
45571	FreeBSD : krb5 -- multiple denial of service vulnerabilities (9ac0f9c4-492b-11df-83fb-0015587e2cc1)	Nessus	FreeBSD Local Security Checks	high
45354	openSUSE Security Update : krb5 (krb5-2188)	Nessus	SuSE Local Security Checks	medium

Detections

Analytics

CVE-2010-0628

high

Tenable Plugins

high

medium

medium

high

medium