3.5 - USN-918-1

Executive Summary

Summary
Title	Samba vulnerability

Informations
Name	USN-918-1	First vendor Publication	2010-03-24
Vendor	Ubuntu	Last vendor Modification	2010-03-24
Severity (Vendor)	N/A	Revision	N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score	NA
Base Score	NA	Environmental Score	NA
impact SubScore	NA	Temporal Score	NA
Exploitabality Sub Score	NA

Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:M/Au:S/C:P/I:N/A:N)
Cvss Base Score	3.5	Attack Range	Network
Cvss Impact Score	2.9	Attack Complexity	Medium
Cvss Expoit Score	6.8	Authentication	Requires single instance
Calculate full CVSS 2.0 Vectors scores

Detail

A security issue affects the following Ubuntu releases:

Ubuntu 6.06 LTS Ubuntu 8.04 LTS Ubuntu 8.10 Ubuntu 9.04 Ubuntu 9.10

This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.

The problem can be corrected by upgrading your system to the following package versions:

Ubuntu 6.06 LTS:
samba 3.0.22-1ubuntu3.11

Ubuntu 8.04 LTS:
samba 3.0.28a-1ubuntu4.11

Ubuntu 8.10:
samba 2:3.2.3-1ubuntu3.8

Ubuntu 9.04:
samba 2:3.3.2-1ubuntu3.4

Ubuntu 9.10:
samba 2:3.4.0-3ubuntu5.6

In general, a standard system upgrade is sufficient to effect the necessary changes.

ATTENTION: This update changes the default samba behaviour. For security reasons, it is no longer possible to use wide links and UNIX extensions at the same time. After applying this security update, wide links will be disabled automatically as UNIX extensions are turned on by default. If wide links are required, you can re-enable them by adding "unix extensions = no" to the [global] section of the /etc/samba/smb.conf configuration file.

Details follow:

It was discovered the Samba handled symlinks in an unexpected way when both "wide links" and "UNIX extensions" were enabled, which is the default. A remote attacker could create symlinks and access arbitrary files from the server.