Yahoo hack warning: What happened and should you be worried? | Hacker News Reader

Yahoo hack warning: What happened and should you be worried?

telegraph.co.uk

115 pointssmokinn40 comments

How could someone forge a cookie after stealing the source code? Did yahoo use a hardcoded private key in the code? Then any developer at yahoo could have broken into an account. That cannot be right.

Maybe the cookie generation had some sort of vulnerability (such as length extension) and looking at the source code helped attackers locate it and exploit it.

Yup, perhaps they put the username of the logged in user in an encrypted/signed cookie, and the private key was in the source code.

It doesn't answer your question precisely, but I asked a similar (albeit more incredulous) question a few months back [1] and got a thread full of educated speculation from current and former Yahoo devs.

[1] https://news.ycombinator.com/item?id=13180234

"After disclosing two distinct hacks late last year, one of which implicated a billion users, Yahoo ..."

This is a weird place to use implicated as it makes the reader think those billion users are to blame for the hack. If that's true, it's a human-scale DDOS - no IoT devices needed.

This sort of victim blaming is all too common in the mainstream press:

IRS Says More Taxpayers May Have Been Hacked http://time.com/4000659/irs-taxpayer-hacked-cybercrime/

It wasn't the taxpayers that were hacked - it was the IRS.

Hackers stole personal information from 104,000 taxpayers, IRS says https://www.washingtonpost.com/news/federal-eye/wp/2015/05/2...

Hackers did not steal personal information from 104,000 taxpayers - they stole it from the IRS.

Smaller media outlets often get it right:

Over 700,000 People Got Screwed in Last Year's IRS Data Breach http://gizmodo.com/over-700-000-people-got-screwed-in-last-y...

Maybe the writer was going for "impacted" and either typed it on their phone or they need to go back to school. Affected would of course be a better word.

Grammatical error, along with many others in the article. Nothing sinister about it.

Implicate has a negative connotation in common usage, and for that reason probably isn't the best choice, but it really just means "entwine." In that more traditional sense, the wording makes sense, it is saying they were caught up in the hack.

I don't think it's a new hack it's just that the internal investigation has lead to more findings of the already talked about cookie hack: https://www.tripwire.com/state-of-security/featured/more-yah...

Remember that if you deleted your account the last time a breach was reported, DO NOT attempt to login to that account to check, as this will reset the decativation window of 90 days before permanent deletion.

I made that mistake last time, "deleted" my yahoo account when there was a breach, promptly forgot about doing that, then about 75 days later another breach was announced, so I logged in to "delete" my account....now I have to wait another 90 days before it's gone.

I'd recommend deleting all content associated with the account and removing the address from any third party site (recovery etc).

I would however never actually delete the account.

My concern with deleting the account is that it exposes you to some really nasty impersonation attacks. It is free to keep. Just keep it.

I don't know about Yahoo, but most services will not allow to reregister a previously deleted account.

I vaguely recall that yahoo does recycle old email addresses.

I agree. The act of deleting the account isn't even a guarantee that the data associated with the account will be deleted.

Has anybody ever seen Y! Confidential link pop-up in the bottom right corner of some Yahoo! articles which seemed to redirect to an internal corporate site? It came and went away at least a dozen times and in some instances it stayed for days.

https://www.google.com/search?q="Y%21+Confidential"

Certainly lots of very confused people keep seeing it.

Most of the answers seem to suggest this is some sort of tracking or malware. It is not but you still shouldn't be seeing it. That is only suppose to be seen by Yahoo employees and the internal links are there so they can report bugs easily. It's also present on betas but shouldn't been seen on the outside. It looks like somebody messed up and let it go to prod without having an employee check.

Yahoo has been useless to me and others for years. It's just a holding company for Ali Baba, that also has an email service and a Japanese website.

I wonder how many people got that "a forged cookie may have been used" email. I suppose they're sending it even if the chance is remote

Dear Yahoo user,

We are writing to inform you about a data security issue that may involve your Yahoo account information. We have taken steps to secure your account and are working closely with law enforcement.

What happened?

In November 2016, law enforcement provided Yahoo with data files which a third party claimed was Yahoo user data. We analysed this data with the assistance of external forensic experts and found that it appears to be Yahoo user data. Based on further analysis of this data by the forensic experts, we believe that an unauthorised third party stole data associated with a broader set of user accounts in August 2013, including yours. We have not been able to identify the intrusion associated with this theft. We believe that this incident is likely distinct from the one that we disclosed on 22 September 2016.

What information was involved?

The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. Not all of these data elements may have been present for your account. The investigation indicates that the stolen information did not include passwords in clear text form, payment card data or bank account information. Payment card data and bank account information are not stored on the system that we believe was affected.

What we're doing

We are taking action to protect our users: We are requiring potentially affected users to change their passwords. We invalidated unencrypted security questions and answers so that they cannot be used to access an account. We are constantly enhancing our safeguards and systems that detect and prevent unauthorised access to user accounts. What you can do

We encourage you to follow these security recommendations: Change your passwords and security questions and answers for any other accounts on which you used the same or similar information used for your Yahoo account. Review all of your accounts for suspicious activity. Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information. Avoid clicking on links or downloading attachments from suspicious emails. In addition, please consider using Yahoo Account Key, a simple authentication tool that eliminates the need to use a password on Yahoo altogether.

For more information

For more information about this issue and our security resources, please visit the Yahoo Account security issues FAQs page available at https://help.yahoo.com/kb/index?locale=en_AU&page=content&y=.... Protecting your information is important to us and we are constantly working to strengthen our defences.

Yours sincerely,

Bob Lord Chief Information Security Officer Yahoo

Jeez, how do they still have a positive net worth? Like seriously, obviously their users & user data is worthless, they don't care about it getting stolen, nor do they seem serious about fixing their dilapidated, insecure systems.

This is just a case of poor management, if Google, Facebook, Twitter and others can figure out how to secure their sites, Yahoo can.

And you think those other sites are more secure? The differences are slight. Giant public websites are tricky. It is very hard to deploy real security across such a large team/platform. Even if you make the effort, some security measures simply wont fly, especially in regards to change control or network segmentation. This sort of bug is only one level of the issue.

Open up any random NIST, ISO or even PCI doc to see what is involved above and beyond bug squashing.

I took the OPs comments as referring to the fact that management either:

a) didn't know the company was hacked.

b) claimed they didn't know they were hacked,

c) didn't bother to do proper discovery to quantify the extent of the hack until years later.

And that would have been covered under nist or iso or any other resonable standard. My point is that once you look into these companieas, get beyond the tech stuff, virtually none implement proper security on such large deployments.

>"virtually none implement proper security on such large deployments."

Can you provide a citation for this? Otherwise it seems you are suggesting because Yahoo was lacking that this means all SV tech giants are lacking.

Well, without ndas make it hard to find actual reports, but take ashley-madison. Millions of users, talk of a billion-dollar ipo, and the post-hack report by the canadian and austrailian privacy ministers found they had no formal security plan.

so according to your logic, one massive hack means all sites are insecure ?

No.. working as a compliance attorney, along with all the industry contacts that entails, allong with a steady stream of reports such as the OP (also target et al) gives me grounds to say that proper security is not an industry norm, that the opposite is more likely.

In doubt? Ask around for how many organizations have a dedicated ciso or privacy officer.

And Yahoo the company we are discussing has a full time CISO, now at Facebook:

http://www.businessinsider.com/alex-stamos-leaves-yahoo-to-b...

As does Google: http://www.csoonline.com/article/2928798/security-leadership...

As does Twitter: https://www.linkedin.com/in/mcoates

as does Uber: https://newsroom.uber.com/joe-sullivan-joining-uber-as-first...

As does Apple: http://www.reuters.com/article/apple-encryption-executive-id...

As does Amazon: https://www.rsaconference.com/speakers/stephen_schmidt

So I would say its pretty common. Just because its not common at the Ashley Madisons and Targets doesn't mean its uncommon elsewhere.

Lol, that is like 1% of the industry. For every facebook there are 100s of smaller shops with websites taking money and handling pii. Being not-facebook doesnt mean you arent in the big leagues with millions of customers.

And that 1% of the industry is exactly the context for these comments, the company being discussed here is Yahoo. I guess you didn't read the part where I specified "SV tech giants"?

So you can't actually substantiate your claim that "virtually none implement proper security".

I am not sure why you think that mentioning a second incident makes your statement true for the majority of tech companies.

> If Google, Facebook, Twitter and others can figure out how to secure their sites, Yahoo can.

The other article linked in this thread[1] attributes this attack to a "state-sponsored actor", which is interesting considering that Google was hacked by such an actor [2], but I'm not sure they ever acknowledged it.

I doubt anyone can say for sure that Facebook and/or Twitter haven't been hacked in such a way. If anything, all we can say is that we haven't heard about it.

[1] http://www.telegraph.co.uk/technology/2017/02/16/yahoo-hack-...

[2] http://www.slate.com/blogs/future_tense/2013/10/30/nsa_smile...

Schneier reports that it wasn't a state-sponsored actor, but a criminal group called Group E. He says "state-sponsored actor" is often code for "please don't blame us for our shoddy security because it was a really sophisticated attacker and we can't be expected to defend ourselves against that." [1]

Google is definitely more secure and more proactive at security than Yahoo. You can look through their security whitepaper: they take a systematic approach and they meet and exceed the state of the art.[2] In contrast, Yahoo was hashing passwords with MD5. Here's Ptacek saying "there is no redeeming quality to justify using MD5", in 2007.[3] Yahoo doesn't really have any excuse.

[1] https://www.schneier.com/blog/archives/2016/09/the_hacking_o...

[2] https://drive.google.com/file/d/0B5Y-fwYJF2hLOTVmMzQ1MjAtMDF...

[3] https://web.archive.org/web/http://www.matasano.com/log/958/...

(I'm not affiliated with any of these companies.)

Is there a better source? That link just mentions it in the title and then plugs other articles they've posted for the rest of it.

EDIT: This seems like a better source: http://www.telegraph.co.uk/technology/2017/02/16/yahoo-hack-...

And it ends in a quick how-to for deleting your Yahoo account!

That's surely a death knell for Yahoo, as if it needed another?

You can delete your account here: https://edit.yahoo.com/config/delete_user

You didn't scroll down far enough. They have a paragraph or so of copy way down on the page. Admittedly still weak on detAils though.

Yes, we changed it from https://www.wired.com/2017/02/security-news-week-yahoo-got-h.... Thanks!

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