Software Engineering Institute

Samba provides file and print services for Microsoft Windows, Unix, Linux, and OS X clients. Samba can also act as a Primary Domain Controller (PDC) or as a Domain Member. Samba runs on most Unix-like systems.

Samba versions prior to 3.0.24 pass unchecked user input from RPC messages to /bin/sh when calling externals scripts that are listed in the Samba configuration file. An attacker may be able to exploit this vulnerability by sending specially crafted RPC messages to a vulnerable server.

This vulnerability occurred as a result of failing to comply with recommndation STR02-C of the CERT C Programming Language Secure Coding Standard.

A remote, unauthenticated attacker may be able to execute arbitrary commands.

Apply a patch or upgrade
These vulnerabilities are addressed in Samba version 3.0.25. In addition, patches are available to address this vulnerability in Samba version 3.0.24. Refer to the Samba Security Releases website for more information.

Do not load external shell scripts

From the CVE-2007-2447 entry on the Samba security page:

This defect may be alleviated by removing all defined external script invocations (username map script, add printer command, etc...) from smb.conf.

Restrict access

Limiting access to the Samba server to trusted hosts may mitigate this vulnerability.