$re = '/\w+\s+\d+\s+\d+:\d+:\d+\s+[^\s]+\s\w+\s+\d+\s+\d+:\d+:\d+\s+([^\s]+)/';
$str = 'Sep 20 11:13:18 1x.xx.xx.1xx0 Sep 20 11:13:15 ac.dc1.buttercomom.com ASM:"MONEYPAK_WEBAPP","MONEYPAK_CLASS","Blocked","Attack signature detected","xxxx4520",,"GET /Content/Images/ixx_logo01_module02.gif HTTP/1.1\\r\\nHost: www.xxxxk.com\\r\\nUser-Agent: sxx/1.0x6264944] UP.';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php