Bug 500225 (CVE-2009-1629)

From the oCERT advisory:

AjaxTerm uses a form of random session id generation which can lead to remote session hijacking.

The ajaxterm.js script allocates session ids on the client side using the following method:

var sid=""+Math.round(Math.random()*1000000000);

The javascript random function used in combination with round does not provide sufficient entropy for a unique session id, as the session id is the only unique identifier for the user session it is possible for an attacker to brute force the space of possible id values and attach an existing connection.

This vulnerability also allows Denial Of Service attacks as it is possible to exhaust the available session ids when performing a brute force attack and, depending on the configured AjaxTerm child command, system resources.

Credit: Michael Greb