DuckDuckGo XSS vulnerability | Hacker News Reader

DuckDuckGo XSS vulnerability

twitter.com

46 pointsNZSmartie24 comments

That second link is seriously scary, how would you ever avoid falling for that? Does anyone know how it works? Going to https://tranquil-bits.surge.sh I'm guessing I'm seeing the attacker's form, but it has duckduckgo.com/vpn as the URL and https.

Edit: If you click submit on the VPN form you get "This could have been a phishing page." so it's definitely the attacker's form, that's crazy.

The problem is the XSS vulnerability. This means the attacker can run arbitrary JS on the site, which I assume is used in the second link to modify the form handlers to run the "This could have been a phishing page.". And yes, that could be used to send the credentials somewhere.

There isn't anything you can do to spot this. This is on DuckDuckGo to fix and they not responding to the report for such long time is irresponsible and not really excusable.

They're faking the URL too though - https://duckduckgo.com/vpn isn't a real site or product - it just redirects to a DDG search for vpn. The page is entirely the attacker's, but it shows DDG's domain with https.

It looks like tranquil-bit.surge.sh redirects to http://tranquil-bit.surge.sh/vpn so maybe DDG are somehow setting the URL to whatever the u= param redirects to?

The URL faking is with the HTML5 history API. It's possible to fake any URL on that domain because the JavaScript is executed in the context of that domain.

Wow.

"Reported in March 2017, emailed them 9 times about the issue since then. Still unfixed as of now."

We have corresponded many times about this issue, and have made many changes over that period.

It's not as simple as just shutting down the open proxy because we need an open proxy to adequately protect users' privacy on our site, e.g. for image search. It just needs to be more locked down and more obvious it is a proxy, which we are doing right now (half done already -- CSP rolled out fully, new domains in process).

+ 1

"Update: To clarify, they did respond to my emails, they say they're working on it."

We are working on further fixing this issue. We require an open proxy in some form to protect our users' privacy, though it should be more locked down and more obvious it is a proxy.

> We require an open proxy in some form to protect our users' privacy

Which feature relies on this?

Currently all the features that showcase third-party content on DuckDuckGo, the biggest being image and audio instant answers.

Thanks for the update and follow-up answers.

Could you comment on the "Reported in March 2017, emailed them 9 times about the issue since then. Still unfixed as of now." claim, as it seems imperative to the discussion?

Is there something that can be improved here? Perhaps that inbox not as actively monitored as it could be?

We have real-time monitoring for that inbox and a 24/7 ops team. We have corresponded many times about this issue, and have made many changes over that period.

It's not as simple as just shutting down the open proxy because we need an open proxy to adequately protect users' privacy on our site. It just needs to be more locked down and more obvious it is a proxy, which we are doing right now (half done already).

Content-Type whitelist, CSP, and a separate domain for proxying please? I don’t feel safe using DuckDuckGo now.

CSP has already been rolled out and we're working on another domain now; we will do a proxy.duckduckgo.com in the interim.

https://ddg.gg/html/

No fancy quick-result box, but fast as lightning.

Wow. The example in the tweet would completely fool me. If you just go to the address bar and press enter ("reloading" the page, but actually going to the address), you can see it's just a search.

https://twitter.com/hexdefined/status/940183455509262336

Thank you, just the push I've been needing. As of this moment, I'm off to ixquick/startpage, which for one thing doesn't require me to go all laid-back and inclusive on the JavaScript, and which for another has those nifty proxy-links.

If you just want a search engine without Javascript try https://duckduckgo.com/html

Adding to Firefox is easy via https://addons.mozilla.org/en-US/firefox/addon/duckduckgo-ht...

That's one trick I had somehow missed. Mind you, that's extremely barebones, not as much as a link to any image-search or options.

Can someone explain what I'm seeing? As far as I can tell, both those links really do leave me on DDG webpages. The only requests according to firebug are to duckduckgo.com. What am I missing (or has this since been fixed)?

It has since been fixed.

There's a typo in the title - it should be "XSS on DuckDuckGo"

Reply on news.ycombinator.com