Debian DSA-2129-1 : krb5 - checksum verification weakness

low Nessus Plugin ID 50865

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Synopsis

The remote Debian host is missing a security-related update.

Description

A vulnerability has been found in krb5, the MIT implementation of Kerberos.

MIT krb5 clients incorrectly accept 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.

The Common Vulnerabilities and Exposures project has assigned CVE-2010-1323 to these issues.

Solution

Upgrade the krb5 packages.

For the stable distribution (lenny), these problems have been fixed in version 1.6.dfsg.4~beta1-5lenny6.

The builds for the mips architecture are not included in this advisory. They will be released as soon as they are available.

See Also

https://security-tracker.debian.org/tracker/CVE-2010-1323

https://www.debian.org/security/2010/dsa-2129

Plugin Details

Severity: Low

ID: 50865

File Name: debian_DSA-2129.nasl

Version: 1.18

Type: local

Agent: unix

Published: 12/2/2010

Updated: 1/4/2021

Dependencies: ssh_get_info.nasl

Risk Information

VPR

Risk Factor: Low

Score: 1.4

CVSS v2

Risk Factor: Low

Base Score: 2.6

Temporal Score: 1.9

Vector: AV:N/AC:H/Au:N/C:N/I:P/A:N

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: Low

Base Score: 3.7

Temporal Score: 3.2

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:krb5, cpe:/o:debian:debian_linux:5.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 12/1/2010

Reference Information

CVE: CVE-2010-1323

BID: 45118

DSA: 2129