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vulnerability bulletin CVE-2009-0845
MIT krb5: denial of service via SPNEGO
Synthesis of the vulnerability
| An attacker can use a SPNEGO authentication in order to stop MIT Kerberos. |
Severity: 2/4.
Creation date: 26/03/2009.
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Impacted products
Description of the vulnerability
The SPNEGO (Simple and Protected GSSAPI NEGOtiation Mechanism, RFC 4178) mechanism is used to negotiate an authentication protocol. The MIT Kerberos server implements SPNEGO.
Two token types are defined: negTokenInit and negTokenResp. The NegTokenInit token contains a bit field named ContextFlags.
When the Kerberos client sends a NegTokenInit with an invalid ContextFlags flag, a NULL pointer is dereferenced in the spnego_gss_accept_sec_context() function of the lib/gssapi/spnego/spnego_mech.c file. This error stops the MIT Kerberos server.
An attacker can therefore use a malicious SPNEGO authentication in order to stop MIT Kerberos. |
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Characteristics
Title: MIT krb5: denial of service via SPNEGO.
Keywords: 4178 ContextFlags GSSAPI Kerberos MIT Mechanism NEGOtiation NULL NegTokenInit Protected RFC SPNEGO Simple denial krb5 negTokenInit negTokenResp service spnego_gss_accept_sec_context spnego_mech.
Identifiers: 256728, 6822062, 6822066, BID-34257, CVE-2009-0845, DSA 1766-1, FEDORA-2009-2834, FEDORA-2009-2852, MDVSA-2009:082, MITKRB5-SA-2009-001, MITKRB5-SA-2009-002, SUSE-SA:2009:019, VIGILANCE-VUL-8568, VMSA-2010-0016, VMSA-2010-0016.1.
Pointed by: VIGILANCE-VUL-8608.
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Information sources
Solutions for this vulnerability
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