Forum Discussion

Zach_C_355943's avatar
Zach_C_355943
Icon for Nimbostratus rankNimbostratus
Mar 16, 2018

Issues with X-XSS Protection HTTP Header

Hey folks, we recently implemented some HTTP headers onto our F5 irules and recently noticed that one of them (X-XSS-Protection) isn't showing up. At the moment, we have them in place in our irule ...
BIG-IP
devops
http header
irule
iRules
security
  • Zach_C_355943's avatar
    Zach_C_355943
    Apr 25, 2018

    Following up! Turns out the answer is we needed to have these headers under "HTTP_RESPONSE" (not REQUEST). What it looks like in a working state in our irules:

    when HTTP_RESPONSE {
  HTML Headers for PCI failures
 if { !([HTTP::header exists "X-Frame-Options"])} { HTTP::header insert "X-Frame-Options" "SAMEORIGIN" }
 if { !([HTTP::header exists "X-XSS-Protection"])} { HTTP::header insert "X-XSS-Protection" "1; mode=block" }
 if { !([HTTP::header exists "X-Content-Type-Options"])} { HTTP::header insert "X-Content-Type-Options" "'nosniff'" }
}
Lee_Sutcliffe's avatar
Lee_Sutcliffe
Icon for Nacreous rankNacreous
Mar 16, 2018

At first glance I can't see anything wrong with your iRule. Could you try the following? I've added logging to the X-XSS-Protection if statement to see if it already exists and what it's value is.

Have you also tried this in a web browser developer window and received the same results?

when HTTP_REQUEST {
 if { !([HTTP::header exists "X-Frame-Options"])} { 
   HTTP::header insert "X-Frame-Options" "SAMEORIGIN" 
 }
 if { !([HTTP::header exists "X-XSS-Protection"])} { 
   HTTP::header insert "X-XSS-Protection" "1; mode=block"
 } else {
   log local0. "Header X-XSS-Protection exists, Value:[HTTP::header value X-XSS-Protection]"
 }
 if { !([HTTP::header exists "X-Content-Type-Options"])} { 
   HTTP::header insert "X-Content-Type-Options" "'nosniff'" 
 }
}