Potential Arbitrary File Access

Summary: A remote attacker may be able to gain access
to files which exist outside of the share’s
defined path. Such files must still be readable
by the account used for the connection.

Patch Availability

The patch for Samba 3.0.2a and earlier releases 3.0.x
(samba-3.0.2a-reduce_name.patch) can be downloaded
from http://www.samba.org/samba/ftp/patches/security/

Samba 2.2.12 has been released to specifically address
this bug.

Description

A bug in the input validation routines used to convert DOS
path names to path names on the Samba host’s file system
may be exploited to gain access to files outside of the
share’s path defined by smb.conf.

Protecting Unpatched Servers

Samba file shares with ‘wide links = no’ (a non-default setting)
in the service definition in smb.conf are not vulnerable to
this attack.

The Samba Team always encourages users to run the latest stable
release as a defense of against attacks. However, under certain
circumstances it may not be possible to immediately upgrade
important installations. In such cases, administrators should
read the “Server Security” documentation found at
http://www.samba.org/samba/docs/server_security.html.

Credits

Both security issues were reported to Samba developers by
iDEFENSE (http://www.idefense.com/). Karol Wiesek is credited
with this discovery.

Our Code, Our Bugs, Our Responsibility.

			-- The Samba Team