[UNIX] Webmin and Usermin PAM Authentication Bypass Vulnerability

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Webmin and Usermin PAM Authentication Bypass Vulnerability
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SUMMARY

" <http://www.webmin.com/> Webmin is a web-based system administration
tool for Unix." " <http://www.webmin.com/index6.html> Usermin is a web
interface that allows all users on a Unix system to easily receive mails
and to perform SSH and mail forwarding configuration."

Lack of proper header validation allows attackers to bypass authentication
and execute arbitrary code with root privileges in Webmin and Usermin.

DETAILS

Vulnerable Systems:
* Webmin version 1.220
* Usermin version 1.150

Immune Systems:
* Webmin version 1.230
* Usermin version 1.160

Miniserv.pl is a webserver program that both Webmin and Usermin use.
Miniserv.pl carries out named pipe communication between the parent and
the child process during the creation and Confirmation of effectiveness of
a session ID (session used for access control via the Web).

Miniserv.pl does not check whether meta-characters, such as line feed or
carriage return, are included with user supplied strings during the PAM
(Pluggable Authentication Modules) authentication process.

Exploitation therefore, could make it possible for attackers to bypass
authentication and execute arbitrary command as root.

ADDITIONAL INFORMATION

The information has been provided by <mailto:snsadv@lac.co.jp> snsadv.
The original article can be found at:
<http://www.lac.co.jp/business/sns/intelligence/SNSadvisory_e/83_e.html>
http://www.lac.co.jp/business/sns/intelligence/SNSadvisory_e/83_e.html

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