Teaching SpamAssassin about the Microsoft KLEZ virus.

Adding lines like the ones below does a pretty good job about tagging
the KLEZ virus as spam. It does miss some of the KLEZ variations
because the KLEZ_CONTENT is slightly different.

$ grep -i klez /usr/share/spamassassin/*
/usr/share/spamassassin/20_body_tests.cf:rawbody KLEZ_IFRAME            /iframe
 src=3Dcid:/i
/usr/share/spamassassin/20_body_tests.cf:describe KLEZ_IFRAME           Frame u
sed by the KLEZ virus
/usr/share/spamassassin/20_body_tests.cf:rawbody KLEZ_CONTENT           /TVqQAA
MAAAAEAAAA/i
/usr/share/spamassassin/20_body_tests.cf:describe KLEZ_CONTENT          Content
 of part of the KLEZ virus
/usr/share/spamassassin/50_scores.cf:score KLEZ_IFRAME              10.0
/usr/share/spamassassin/50_scores.cf:score KLEZ_CONTENT             10.0