Moodle 1.8 before 1.8.11 and 1.9 before 1.9.7 does not use a random password salt in config.php, which makes it easier for attackers to conduct brute-force password guessing attacks.
docs.moodle.org/en/Moodle_1.8.11_release_notes
docs.moodle.org/en/Moodle_1.9.7_release_notes
moodle.org/mod/forum/discuss.php?d=139111
secunia.com/advisories/37614
www.securityfocus.com/bid/37244
www.vupen.com/english/advisories/2009/3455
www.redhat.com/archives/fedora-package-announce/2009-December/msg00704.html
www.redhat.com/archives/fedora-package-announce/2009-December/msg00730.html
www.redhat.com/archives/fedora-package-announce/2009-December/msg00751.html