PayPal.com XSS Vulnerability

http://seclists.org/fulldisclosure/2013/May/163

by instakill • 13 years ago

243 71 13 years ago

seclists.org

MysticFear• 13 years ago

The downside of Child Labor laws.

icebraining2• 13 years ago

The Chromium Security team pays bounties to adults representing minors; Paypal could have done the same.

droopybuns3• 13 years ago

If the feds were to audit the situation you are describing, I would wager they'd come after Google.

Google has a lot more freedom and track record for asking forgiveness instead of permission than Paypal (i.e. wifi sniffing in google cars). They are not a payment processing company.

This stuff is complicated. Never attribute to malice that which is adequately explained by stupidity.

cft• 13 years ago

Can you explain why this is a real vulnerability? The user himself must put that JS in the search box.

nemothekid• 13 years ago

I could set up a redirect to POST data to that search form and steal his cookies/replace the page with a login form/all the fun you get running arbitrary javascript.

deckar01• 13 years ago

If you can redirect someone to that page you could redirect them to any page... But they want to go to PayPal, you send them there, and you pass along some post data to hijack their session.

gingerlime2• 13 years ago

As an example, an attacker can craft a script that would run within the paypal.com domain name. The script can therefore potentially grab the user paypal session (if the user is already logged in). Otherwise, it can show any information the attacker wants, and to the user this looks like a real trustworthy paypal page. It is running on the paypal.com domain, and the browser shows it's secured and trusted. So for example, it can display the login page and asking to confirm the password, or keylog anything the user presses etc.

This link can be embedded on a different site, or sent via email, and because the link itself points to paypal.com - it is much more likely to be trusted by unsuspecting users.

bluetooth4• 13 years ago

> This link can be embedded on a different site, or sent via email, and because the link itself points to paypal.com - it is much more likely to be trusted by unsuspecting users.

Doesn't seem like that is the case here. The bug is in the search form, which is POST only. It wouldn't be enough to share the link to the search page, you'd need something that does the search on your behalf.

pfg• 13 years ago

Basically you need to put something like this on a page you control (where "xss code" is the code triggering the XSS):

    <form action="https://www.paypal.com/de/cgi-bin/searchscr?cmd=_sitewide-search" method="post">
        <input type="text" name="queryString" value="xss code" />
    </form>

Then, just as the page loads, submit that form and you're executing JS on a paypal.com page. This would work great for phishing or session hijacking.

hidden-markov• 13 years ago

Isn't this CSRF?

bluetooth4• 13 years ago

Although the user has to place in the payload himself to exploit this vulnerability, there are a few ways the attacker can use this. The most obvious and simplest to do is to create a form that does the search for the user, and thus fills out the form for the user, exploiting this vulnerability. You could have the form submit automatically via javascript on page load, requiring no user interaction.

Once the form has been submitted on behalf of the user, you have javascript execution in the context of paypal.com, and can do pretty much anything. Send the contents of your account to another address, shut down the account, exfiltrate past transaction data, etc.

psychometry• 13 years ago

I'm sure PayPal is using some form or CSRF protection to prevent a POST from some external site from working.

MarkTanamil• 13 years ago

bitcoin user not affected

bluetooth4• 13 years ago

MtGox, BTC-e, among other big bitcoin exchanges have been hacked before.

ethanaustinite• 13 years ago

Bitcoin is not mtgox or any other exchange. But to be fair, bitcoin itself had its share of security issues (fixed, but who knows what the future holds)

jamesbrennan• 13 years ago

It looks like the vulnerability has been patched. Can anyone confirm if they can still successfully exploit this?

ancarda2• 13 years ago

Is there any legitimate reason to discriminate because of age?

droopybuns3• 13 years ago

The Federal Labor Standards Act has provisions about anyone under the age of 18 working for companies whose revenue is greater than $500,000. It sucks to be a kid for a lot of reasons.

This kid just blamed Paypal for one of our country's many idiotic federal laws.

This choice should be considered a career limiting decision by any hiring manager.

ancarda2• 13 years ago

Couldn't they just pay him once he turns 18? Or at the least reward him in some other way.

cperciva2• 13 years ago

This choice should be considered a career limiting decision by any hiring manager.

Are you saying that you're holding a 17 year old student in Germany responsible for not understanding US labor laws?

polemic• 13 years ago

They didn't have to pay him.

Still very poorly handled. Should've gone something like:

1. "Hey, that's awesome that you found that, thanks!"

2. "For very good reasons (a), (b) and (c) we can't actually pay you, that really sucks :("

3. "But hey we like your style, so how about we fly you over for an internship when you've finished school / investigate if Germany has different rules / look at scholorship options and a great reference / [one of a million other things you could do to help a kid out"

Karunamon• 13 years ago

Wait, it's considered "working for" when there's no employment relationship of any kind?

shmerl2• 13 years ago

Can they frame the bounty not as a payment? But like some kind of prize etc.

georgemcbay• 13 years ago

"This choice should be considered a career limiting decision by any hiring manager."

Hopefully not forever. When I was young and stupid and the net was a much simpler place I casually fully disclosed the problem with posting your Cisco configs with "encrypted" passwords to Usenet:

https://groups.google.com/d/msg/comp.dcom.sys.cisco/WjuKAOQL...

I would not do something like this today, especially not in such a full-of-myself douchey manner.

Sadly a lot of postings to the internet are basically "forever" at this point and combined with the insistence of so many companies that real names be used, we're going to have generations of younger folks who say or do something stupid (because they are young and stupid) that they can never get rid of. And that's unfortunate.

nknighthb• 13 years ago

The Fair Labor Standards Act places no limitations on the work of 16 and 17 year olds in non-hazardous jobs, and in any case does not concern itself with non-employment relationships like the one Paypal would have had with this 17-year-old.

There is a reason that you read about minors running their own businesses all the time. The laws are targeted at employment that is exploitative or interferes with a child's education. Not at things like this.

oijaf888• 13 years ago

How do those apply in Germany? Do all subsidiaries in all countries have to follow FLSA? I assume Paypal's German subsidiary is only responsible for following German employment law.

SamReidHughes• 13 years ago

You should try not coming up with bad reasons to not hire qualified candidates.

homakov• 13 years ago

1. seriously, you couldn't just say you're 18? nobody cares in fact.

2. well, fuck paypal!

3. not a good way to show PoC. Is there antiCSRF on search form? Can I see the whole flow?

tudorconstantin• 13 years ago

Paypal being penny wise but pound fool.

The next person who'll discover something, will probably monetize it on the black market.

schlecht• 13 years ago

As so many do.

leke• 13 years ago

Too young to be a hacker, but not too young to jail for being a hacker :D

cstrat• 13 years ago

It's weird that PayPal replaced one of the instances of </script> with </skript>?

lawnchair_larry• 13 years ago

Not the first time I've seen paypal flake on their bounty. Poor excuse.

jremop2• 13 years ago

On a sidenote, does anyone have a good setup for browsing securely to avoid issues like this? I ran with JS restricted to a whitelist for a while, but many random websites that I have to use require it these days.

Can you use something like Ghostery to allow any site to do its own JS but not external JS, besides whitelisted sites/externals?

ars• 13 years ago

> Can you use something like Ghostery to allow any site to do its own JS but not external JS, besides whitelisted sites/externals?

That's exactly what noscript does. Use the option "Temporarily allow top-level sites by default->Base 2nd level Domains".

jremop2• 13 years ago

Thanks! This looks like exactly the behavior I want.

troels• 13 years ago

Run your browser in private mode, or create a separate user account and run the browser under that. Or just use a different browser for the "secure stuff" (E.g. your online banking etc.). Then it doesn't matter what kind of xss trickery they throw at you, cause your cookies aren't accessible to the browser.

I suppose it might be useful with a browser extension/feature that allowed you to lock access to certain site's cookies until you have explicitly granted use. Sort of like how the keychain works on os x.

tzury• 13 years ago

In the last 2 years, I have seen 100's of such on paypal/ebay.

Just to name a few, http://www.xssed.com/search?key=paypal.com

bharathwaaj• 13 years ago

Can somebody explain how that script triggers?

ck2• 13 years ago

PayPal should have put the reward into a trust for them for a year if there were legal issues.

Kudos for them being honest with both the bug and their age regardless.

The future is probably filled with teenagers discovering things, good and bad.

Teenagers are still prosecuted as adults but legally treated as less for other responsibilities.

masklinn• 13 years ago

As x9k noted on /r/netsec (http://www.reddit.com/r/netsec/comments/1f3bt1/17_years_old_...)

* a 12 years old found a stack overflow bug in firefox's document.write, in 2010: http://www.mercurynews.com/san-jose-neighborhoods/ci_1640189... (https://news.ycombinator.com/item?id=1822117)

* "Pinkie Pie" is an anonymous teenager, he won $60k at Pwnium, and did it again at Pwnium 2

* @CimStordal, 15 (at the time), found XSS in Facebook, Apple, Google and Microsoft sites: http://www.internet-security.ca/internet-security-news-archi...

Tech has always been filled with teenagers discovering things, now more than ever. Most bounty handlers treat them as valued contributors, Paypal — as usual — shits all over everything.

yogevyuval• 13 years ago

Add it to your CV

Hymie• 13 years ago

Can you clarify exactly when you reported this XSS as a personal friend of mine reported it (exact same bug with a slightly different XSS vector) and was told it had already been found a reasonable while back.

(From memory, he also took a few photos of it also).

Would be interested to hear your response as it might give this another angle entirely, haha.

My personal experience with PayPal isn't particularly great, I'm a security researcher who's just turned 18, and even when I was underage I never actually disclosed that but regardless I had the following knocked back;

(Whole heap of non-critical XSS's, and two critical stored ones, The ability to edit titles on some PayPal subdomains (without giving too much information out) - This vulnerability still exists but I was told it was quote "not serious" even though the title field was vulnerable to stored XSS.

Full path disclosures, open administrative panels, whole variety of cookie/SSL/TSL based issues which I was told did not warrant a bounty.

Also had a personal friend (the same guy who found the XSS you've posted here) find a couple SQLi's on a few PayPal domains (post-auth) and he still hasn't heard back from them.

I'm not going to be the guy to accuse PayPal of not playing fair here, but my friend has also reported vulnerabilities I had previously reported and gotten paid for them. (Might be because he reports them from his security company email, whereas I was reporting them as an individual).

Anyway, Sad to hear you didn't get a bounty!

Also, if you don't have it here's a pretty good bug bounty list; http://bugcrowd.com/list-of-bug-bounty-programs/

PayPal.com XSS Vulnerability

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