#PHP Regular Expressions
#All comment lines must have '#' as the first character of the line. 
#More critical rules should be put higher in the list as only the first pattern matched is reported to the user.

eval\/\*[a-z0-9]+\*\/
eval\([a-z0-9]{4,}\(\$[a-z0-9]{4,}, \$[0-9a-z]{4,}\)\);
(chr\(\d+\^\d+\)\.){4,}
(\$[a-z0-9]{3,}\[\d+\]\.){4,}
chr\(\d+\)\.""\.""\.""\.""\.""
\$GLOBALS\[\$GLOBALS['[a-z0-9]{4,}'\]\[\d+\]\.\$GLOBALS\['[a-z-0-9]{4,}'\]\[\d+\].
\$GLOBALS\['[a-z0-9]{5,}'\] = \$[a-z]+\d+\[\d+\]\.\$[a-z]+\d+\[\d+\]\.\$[a-z]+\d+\[\d+\]\.\$[a-z]+\d+\[\d+\]\.
eval\([a-z0-9_]+\(base64_decode\(
\$[a-z]{3,}=\$[a-z]{3,}\("",\$[a-z]{3,}\);\$[a-z]{3,}\(\);
{\s*eval\s*\(\s*\$
Googlebot['"]{0,1}\s*\)\){echo\s+file_get_contents
eVaL\(\s*trim\(\s*baSe64_deCoDe\(
if\s*\(\s*mail\s*\(\s*\$mails\[\$i\]\s*,\s*\$tema\s*,\s*base64_encode\s*\(\s*\$text
fwrite\s*\(\s*\$fh\s*,\s*stripslashes\s*\(\s*@*\$_(GET|POST|SERVER|COOKIE|REQUEST)\[
echo\s+file_get_contents\s*\(\s*base64_url_decode\s*\(\s*@*\$_(GET|POST|SERVER|COOKIE|REQUEST)
chr\s*\(\s*101\s*\)\s*\.\s*chr\s*\(\s*118\s*\)\s*\.\s*chr\s*\(\s*97\s*\)\s*\.\s*chr\s*\(\s*108\s*\)
(\$OOO_O_000_\{\d+\}.){3,}

#Detects the '_' character encoded in a string like "\x5F".  '_' is present in many functions that malware would want to hide.
\\[Xx](5[Ff])

#Detects the '_' character placed inside a call to the 'chr()' function
chr\s*\(\s*['"]?\s*((95)|(0[Xx]5[Ff]))\s*['"]?\s*\)

#Detects generic base64 strings longer than 260 characters enclosed in quotes ending with 0-3 '=' chars.
#260 was a threshold chosen because strings of 256 characters are common enough.  Might increase later to reduce false positives.
['"][A-Za-z0-9+\/]{260,}={0,3}['"]

#Detects long single lines contained within PHP tags.
#We can increase from 750 later if we need to.
^.*<\?php.{750,}\?>.*$