moodle has an arbitrary SQL execution vulnerability.
From the National Vulnerability Database
entry:
SQL injection vulnerability in the hotpot_delete_selected_attempts function in report.php in the HotPot module in Moodle 1.6 before 1.6.7, 1.7 before 1.7.5, 1.8 before 1.8.6, and 1.9 before 1.9.2 allows remote attackers to execute arbitrary SQL commands via a crafted selected attempt.