claro_init_local.inc.php in Claroline 1.7.2 uses guessable session cookies (MD5 hash of connection time), which allows remote attackers to hijack sessions and possibly gain administrative privileges.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24326
http://www.vupen.com/english/advisories/2006/0320
http://www.securityfocus.com/bid/16341