Internet Starter, one of SoftCOM iKSORIS system modules, allows for setting an arbitrary session cookie value. An attacker with an access to users browser might set such a cookie, wait until the user logs in and then use the same cookie to take over the account. Moreover, the system does not destroy the old sessions when creating new ones, what expands the time frame in which an attack might be performed. This vulnerability has been patched in version 79.0
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
Such a scenario is commonly observed when:
In the generic exploit of session fixation vulnerabilities, an attacker creates a new session on a web application and records the associated session identifier. The attacker then causes the victim to associate, and possibly authenticate, against the server using that session identifier, giving the attacker access to the user’s account through the active session.