Scientific Linux Security Update : krb5 on SL7.x x86_64

Medium Nessus Plugin ID 87560


The remote Scientific Linux host is missing one or more security updates.


It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.

A flaw was found in the OTP kdcpreauth module of MIT kerberos. An unauthenticated remote attacker could use this flaw to bypass the requires_preauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack against the user's password. (CVE-2015-2694)

The krb5 packages have been upgraded to upstream version 1.13.2, which provides a number of bug fixes and enhancements over the previous version.

Notably, this update fixes the following bugs :

- Previously, the RADIUS support (libkrad) in krb5 was sending krb5 authentication for Transmission Control Protocol (TCP) transports multiple times, accidentally using a code path intended to be used only for unreliable transport types, for example User Datagram Protocol (UDP) transports. A patch that fixes the problem by disabling manual retries for reliable transports, such as TCP, has been applied, and the correct code path is now used in this situation.

- Attempts to use Kerberos single sign-on (SSO) to access SAP NetWeaver systems sometimes failed. The SAP NetWeaver developer trace displayed the following error message :

No credentials were supplied, or the credentials were unavailable or inaccessible Unable to establish the security context

Querying SSO credential lifetime has been modified to trigger credential acquisition, thus preventing the error from occurring. Now, the user can successfully use Kerberos SSO for accessing SAP NetWeaver systems.


Update the affected packages.

See Also

Plugin Details

Severity: Medium

ID: 87560

File Name: sl_20151119_krb5_on_SL7_x.nasl

Version: $Revision: 2.3 $

Type: local

Agent: unix

Published: 2015/12/22

Modified: 2016/08/02

Dependencies: 12634

Risk Information

Risk Factor: Medium


Base Score: 5.8

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N

Vulnerability Information

CPE: x-cpe:/o:fermilab:scientific_linux

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/RedHat/release, Host/RedHat/rpm-list

Patch Publication Date: 2015/11/19

Reference Information

CVE: CVE-2014-5355, CVE-2015-2694