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TITLE:
MIT Kerberos Telnet Client Buffer Overflow Vulnerabilities

SECUNIA ADVISORY ID:
SA14745

VERIFY ADVISORY:
http://secunia.com/advisories/14745/

CRITICAL:
Moderately critical

IMPACT:
System access

WHERE:
>From remote

SOFTWARE:
Kerberos V5
http://secunia.com/product/556/

DESCRIPTION:
Gael Delalleau has reported two vulnerabilities in Kerberos V5, which
can be exploited by malicious people to compromise a vulnerable
system.

1) A boundary error in the "slc_add_reply()" function in the included
telnet client when handling LINEMODE suboptions can be exploited to
cause buffer overflow via a specially crafted reply containing a
large number of SLC (Set Local Character) commands.

2) A boundary error in the "env_opt_add()" function in the included
telnet client when handling NEW-ENVIRON suboptions can be exploited
to cause a heap-based buffer overflow via a specially crafted reply
containing a large number of characters that need escaping.

Successful exploitation allows execution of arbitrary code, but
requires that a user connects to a malicious server with the
vulnerable telnet client.

The vulnerabilities affect versions up to and including release
krb5-1.4.

SOLUTION:
Apply patch:
http://web.mit.edu/kerberos/advisories/2005-001-patch_1.4.txt
http://web.mit.edu/kerberos/advisories/2005-001-patch_1.4.txt.asc

PROVIDED AND/OR DISCOVERED BY:
Gaël Delalleau

ORIGINAL ADVISORY:
MIT:
http://web.mit.edu/kerberos/www/advisories/MITKRB5-SA-2005-001-telnet.txt

iDEFENSE:
http://www.idefense.com/application/poi/display?id=220&type=vulnerabilities
http://www.idefense.com/application/poi/display?id=221&type=vulnerabilities

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