Forum Discussion

NickAD's avatar
NickAD
Icon for Cirrus rankCirrus
Apr 13, 2017

iRule to block string in header and display blocking page

I am wondering if I can create an iRule to block a request if a certain string appears anywhere in the header.

For example, it would be something like...

when HTTP_REQUEST {
if { [HTTP::header "User-Agent"] contains "test1234" } {
drop
return }
}

Except I would not want the block to be limited to the User-Agent. I would want it to be blocked no matter where "test1234" appeared in the header.

A follow-up to that would be if I can also have this iRule display the blocking page with a SupportID. I would like those testing to be able to have visual confirmation to see it worked and so they can easily share it with others.

ASM Advanced WAF
asm irules
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irule
security
  • Vijay_E's avatar
    Vijay_E
    Icon for Cirrus rankCirrus
    Apr 13, 2017

    I have never tried this but you may be able to get something along this line working:

    when HTTP_REQUEST {
  foreach header_var [HTTP::header names] {
    if { [HTTP::header header_var] contains "test1234" } {
      drop
      return }
}
}
  • Snl's avatar
    Snl
    Icon for Cirrostratus rankCirrostratus
    Apr 14, 2017

    Try below 

     when HTTP_REQUEST {
   log local0. "[IP::client_addr]:[TCP::client_port]: User-Agent: [string tolower [HTTP::header "User-Agent"]] requested [HTTP::host][HTTP::uri]"
      if { [string tolower [HTTP::header "User-Agent"]] contains "test1234"} {
  log local0. "[IP::client_addr]:[TCP::client_port]: Rejected request"
  reject   }}