Invision Power Board v2.1.4 - session hijacking

[Hans Wolters <hans.wolters@xxxxxxxxx>]

Problem:

Invision Board v2.1.4 has a problem with sessions. Once it is  
installed on a server where php is allowed to
use transparant sessions a session can be hijacked by other users.



Testing:

Once you visit a site where Invision Board is used the first click on  
the Log In link points the visitor to a link with the session id in it:

index.php?s=<session_id>&act=Login&CODE=00

If you copy this session id, login and start a different browser (not  
a new instance) then you only need to copy the session id url into  
the different browser to login without giving the password and login  
name.

Any links within the forum where the session_id is linked to the url  
will enable other people (perhaps only
within the same network where the ipnumber is natted) to login when  
users are online and logged in.

Reported:

Contacted the authors on march 1st, no response.
Contacted the author via the email address listed on this list, no  
respons.

Regards,

Hans