[UNIX] Samba SAMR Change Password Command Injection Vulnerability

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Samba SAMR Change Password Command Injection Vulnerability
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SUMMARY

<http://samba.org/samba/ > Samba is "a Unix server application used to
implement Windows file sharing and domain controlling functionality. SAMR
is the named pipe used to access the SAM, security accounts manager,
database. This database stores login credentials on NT based systems".

Remote exploitation of a command injection vulnerability within Samba
Project's Samba could allow an attacker to execute arbitrary code with
nobody privileges.

DETAILS

Vulnerable Systems:
* Samba version 3.0.24.
* Previous versions of Samba release 3 may be vulnerable.
* Release version 2 and below did not have this feature.

The vulnerability exists within the code responsible for updating a user's
password in the SAM database. Unfiltered user input is passed to
"/bin/sh". This allows an attacker to execute arbitrary shell commands
with the privileges of the nobody user.

Successful exploitation of this vulnerability allows an attacker to run
arbitrary shell commands with the privileges of the nobody user.

An important mitigating factor is that this vulnerability occurs within a
non-default configuration of Samba. Specifically, the 'username map
script' option must be defined in the smb.conf file.

Valid credentials are not needed to exploit this vulnerability. In order
to successfully change a password, it is necessary to provide the original
password. However, the vulnerability can still be triggered regardless of
whether or not the change password attempt fails.

Workaround:
Removing the 'username map script' option from the smb.conf file will
prevent this vulnerability from being triggered.

CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2447>
CVE-2007-2447

Disclosure Timeline:
* 05/07/2007 Initial vendor notification
* 05/07/2007 Initial vendor response
* 05/14/2007 Coordinated public disclosure

ADDITIONAL INFORMATION

The information has been provided by iDefense.
The original article can be found at:

<http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=534>

http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=534

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