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Mod_auth_kerb: Denial of Service


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200701-14 / mod_auth_kerb
Release Date January 22, 2007
Latest Revision December 30, 2007: 02
Impact normal
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
www-apache/mod_auth_kerb < 5.0_rc7-r1 >= 5.0_rc7-r1 All supported architectures

Related bugreports: #155782


Mod_auth_kerb is vulnerable to a buffer overflow possibly allowing a Denial of Service.

2.  Impact Information


Mod_auth_kerb is an Apache authentication module using Kerberos.


Mod_auth_kerb improperly handles component byte encoding in the der_get_oid() function, allowing for a buffer overflow to occur if there are no components which require more than one byte for encoding.


An attacker could try to access a Kerberos protected resource on an Apache server with an incorrectly configured service principal and crash the server process. It is important to note that this buffer overflow is not known to allow for the execution of code.

3.  Resolution Information


There is no known workaround at this time.


All mod_auth_kerb users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apache/mod_auth_kerb-5.0_rc7-r1"

4.  References


Page updated January 22, 2007

Summary: This is a Gentoo Linux Security Advisory

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