iRule to log for Microsoft Security Advisory (2659883) Vulnerability in ASP.NET Could Allow Denial of Service?

when RULE_INIT {
 We want to check the payload for 500 or more parameter=value pairs
set static::pattern "[string repeat *& 500]*"
}
when HTTP_REQUEST {
 Collect up to 1Mb of POST data
if { [HTTP::method] equals "POST"}{ 
set clength 0
if {[HTTP::header "Content-Length"] ne "" && [HTTP::header "Content-Length"] <= 1048576 }{ 
set clength [HTTP::header Content-Length]
} else { 
set clength 1048576 
}
if { $clength > 0} {
HTTP::collect $clength
} 
}
}
when HTTP_REQUEST_DATA {
 Check if the collected payload matches the pattern
if {[HTTP::payload] matches_glob $static::pattern} {
log local0.alert "Microsoft Security Advisory (2659883)\
IP Address [IP::client_addr]:[TCP::client_port] requested [HTTP::uri]"
 Drop the request
drop
}
}