Matching ASCII codes %00 - %1f in HTTP::uri

And actually, if you wanted to trap ALL of the control characters from %00 to %1f...

Note that %1, %2, etc would pass through unmatched as the regex is looking for percent, followed by single digit 0 or 1, followed by single digit 0 through 9 or a though f or A through F.

when HTTP_REQUEST {
    log local0. "Checking URI: [HTTP::uri]"
    if { [regexp {%[0-1][0-9a-fA-F]} [HTTP::uri]] } {
        log local0. "Illegal URI: Closing Connection."
        HTTP::close
        TCP::close
    }
}