The following rules might help out in protecting a site against SQL injection:
[ISAPI_Rewrite] RewriteRule .*(?:global.asa|default\.ida|root\.exe|\.\.).* . [F,I,O] RewriteRule .*(?:DECLARE).* /null.htm [F,I] RewriteRule ^.*\+update\+.*$ /null.htm [F,I] RewriteRule ^.*SUBSTRING\(.*$ /null.htm [F,I] RewriteRule ^.*CHARINDEX.*$ /null.htm [F,I] RewriteRule ^.*NVARCHAR.*$ /null.htm [F,I] RewriteRule ^.*CHAR\(.*$ /null.htm [F,I] RewriteRule ^.*CAST\(.*$ /null.htm [F,I] RewriteRule ^.*%20xp_.*$ /null.htm [F,I] RewriteRule ^.*%20@.*$ /null.htm [F,I] RewriteRule ^.*@%20.*$ /null.htm [F,I] RewriteRule ^.*';*$ /null.htm [F,I] RewriteRule ^.*EXEC\(@.*$ /null.htm [F,I] RewriteRule ^.*sp_password.*$ /null.htm [F,I]
F – forbidden
I – Ignore case