Why using proxy tries to hit http://burpsuite

[ferasdour]

When trying to access a site, like this:
echo "example.com"|/root/.pdtm/go/bin/katana -nc -silent -c 30 -p 10 -jc -kf -no-sandbox -proxy http://172.25.128.1:8080
The request received by the proxy is just this:
GET / HTTP/1.1 Host: burpsuite User-Agent: Go-http-client/1.1 Accept-Encoding: gzip
I'm getting in my proxy (caido and zap) a request to "burpsuite:80" and it doesn't really make sense why. Can someone help or tell me i'm doing it wrong?

[bill-e-ghote]

Same here. Why is this happening?

[ferasdour]

I think i found it, it's because it pulls in the proxy util from the project discovery utils and does an isburp check:

katana/pkg/engine/common/http.go

Line 47 in f8486d4

if ok, err := proxyutil.IsBurp(options.Proxy); err == nil && ok {

https://github.com/projectdiscovery/utils/blob/main/proxy/burp.go#L14

I don't understand why thats a thing exactly, and the commit doesn't clearly explain the need for it:
projectdiscovery/utils@4701095

but I an see where in the code it happens at least, so that's.... something.