Skip to main content

Hitachi ID Systems Blogs

Posts Tagged ‘changing passwords at 100 million user scales.’

eBay compromise – the largest incident yet?

Thursday, May 22nd, 2014

It seems that compromised password databases are getting bigger and bigger.

The latest one is a report that 145 million user account records (i.e., username, hashed password, some profile information such as date of birth) were exfiltrated from eBay.

(Gotta love that word … exfiltrated.)

I don’t know what attack vector was used to compromise this data, other than that the attack was carried out from inside the eBay corporate network, so discussing that will have to wait for another day.

As the scale of these incidents gets larger, new problems arise. For example, eBay (the corporation) has reacted very responsibly here – disclosing what they know and advising users to change their passwords. Users are getting used to these kinds of incidents and are trying to change their passwords. So far, so good.

But there are 145,000,000 users trying to change their passwords, more or less all at the same time. The eBay web site clearly cannot keep up. I tried to change my password, but failed:

  • First, it was hard to find the password change screen (but I did find it in the end…)
  • Once I found it, I learned that the eBay site requires confirmation that it’s a legitimate user (me) making the password change, by sending a code to my personal e-mail or phone.
  • But … the system is under such high load that I never got the confirmation e-mail. I tried asking for a text message but the site just refused, complaining about load.
  • What about users who registered an e-mail account with eBay years ago, and no longer have that account? I suppose they cannot change their password – at least not without human assistance, which also won’t scale to 145,000,000 accounts…

In short, at this scale, remediation is a problem. Maybe I’ll try to change my password tonight or tomorrow. Hopefully the storm of password changes will have slowed down by then.

What about users that employ the same password on multiple web sites (i.e., almost everybody)? This incident implies that 100,000,000 or more users are now trying to change their passwords on facebook, reddit, flickr, google, live.com, etc. I bet those sites are slammed too, and perhaps also unable to respond.

All this sounds like a strong argument for federating identity and authentication — but federating to a few large providers (like Google or Microsoft) will concentrate risk. Imagine if Google or Microsoft get compromised, and everybody was using those platforms as federated identity/authentication providers for web sites such as eBay. That would be even worse than the current eBay incident! Moreover, federation creates linkages between accounts on different services, so has the (unintended) effect of diluting privacy.

Ultimately, I think federating to a large number of small providers would be best, because compromise of any one provider would have only modest impact. Unfortunately, we are still very far from such an architecture.

page top page top