Claroline 1.7.2, sso identification vulnerability

[karmaguedon@xxxxxxxxxxx]

hi,
this is what we can read in file "/claroline/inc/claro_init_local.inc.php" :

[...]
$ssoCookieValue      = md5( mktime() );

                $sql = "UPDATE `".$tbl_sso."`
                        SET cookie    = '".$ssoCookieValue."',
                            rec_time  = NOW()
                        WHERE user_id = ". (int) $_uid;

                $affectedRowCount = claro_sql_query_affected_rows($sql);

                if ($affectedRowCount < 1)
                {
                    $sql = "INSERT INTO `".$tbl_sso."`
                            SET cookie    = '".$ssoCookieValue."',
                                rec_time  = NOW(),
                                user_id   = ". (int) $_uid;

                    claro_sql_query($sql);
                }

               $boolCookie = setcookie($ssoCookieName, $ssoCookieValue,
                                       $ssoCookieExpireTime,
                                       $ssoCookiePath, $ssoCookieDomain);
[...]

so, the cookie value must be always unknown.
in this code, the cookie value is the md5 value of the connection time ! really 
unknown ? no.

solution :
desactivate sso service
or
replace mktime() by rand(100,1000000) (for e.g)