As a security precaution, we are requiring ALL members to change their passwords, here: http://www.librarything.com/changepassword.php

A security review and search of our records has determined that LibraryThing suffered a data breach in November of 2011. The breach was narrow. We have found no evidence that any catalog or other book data was accessed, changed or lost. The breach did not include member names, so it is unlikely the hacker(s) were after LibraryThing accounts.

Unfortunately, the hacker(s) did assemble and retrieve two key pieces of data–email addresses and encrypted passwords of members who had listed an email and joined before that date. Our passwords are stored as a one-way encyption (in technical terms, a salted hash). Such hashes are difficult, but not impossible, to break, especially for simple passwords.

Although a minority of accounts were affected, we are requiring all members to change their password to take advantage of increased account security features.

The breach. The hacker(s) gained partial access to our system through a flaw in our WordPress blogging software. Read more in “The Full Details” below.

All evidence points to this being an email-hacking attack. We have every reason to believe no other LibraryThing data was taken, not even user names. The intent was probably to grab the emails for spam, and break the password hashes, if possible. When broken, the passwords could be used against members who used the same password for their email, or email-based services, as they used on LibraryThing. Using the same password across many services is bad practice, but not uncommon. No financial data could have been taken. We do not get or store credit card numbers or any other financial information.

Our response. Security has been tightened significantly since late 2011, and has been further improved across the board since we discovered the event during a security review on January 21st, 2014. We have now moved our WordPress blog off our servers entirely, so a successful hack leads nowhere. Our password and account-recovery systems have been upgraded to meet the highest industry standards, and we have implemented a slate of additional security measures.

Email notices are being sent out to all members with email addresses. You can change your password any time; you don’t need to wait for the email.

Our apology. The hack may come as a shock; it certainly was to us. Although events of this sort–and far worse–have become numbingly frequent, they are failures indeed. I regret and apologize that any such event could happen on my watch, and the rest of the team feels the same way. We are all committed to ensuring that LibraryThing is as secure as possible going forward.

We hope this failure will not sour you on our service or community. LibraryThing members are a dedicated and passionate bunch, and a pleasure and honor to serve. After years of getting by, the company has significant profits to sink back into development of the main site; we will meet this event with renewed dedication and resources. (Please see, and spread, our recent job ad.)

Because the hack undermines a customer relationship, we have chosen to upgrade to “lifetime” accounts all members who joined before November 20th, 2011. We included those who did not have email addresses listed.

Come ask questions and discuss on Talk. You are also welcome to email tim@librarything.com.

Sincerely,

Tim Spalding
Founder and President

The Full Details

What happened:

• The hacker broke into the system through a flaw in WordPress, the blogging software that we use. This gave them only partial access to the system, but was sufficient to query the user database and save the results.
• The breach occurred on November 19th, 2011.
• We have no evidence of further data breaches. They are not impossible. We are confident no similar attacks could have taken place since at least January 2013, when we added some specific security features.
• We discovered the breach on January 21st, 2014. As it happened so long ago, we believe whatever damage could be done, has already been done.
• We waited two weeks in order to understand the attack and to implement a new password system and a series of other security steps before going public, and potentially drawing hacker interest.

What was taken:

• The hacker(s) exported three fields: email address, password hash and the IP address at sign-up. (The IP would not be of much use to them.)
• Only members with accounts opened before November 20th, 2011, with email addresses, were affected. In total, 685,259 emails were exported.
• We have no indication that other LibraryThing data was accessed or taken. It is significant that the hacker didn’t even export LibraryThing user ids or user names. They were surely after emails and passwords, not book data.
• LibraryThing does not receive or store credit card information or any other financial details. If you registered for a paid account via PayPal, PayPal has your credit card information, but they do not send the numbers to us.
• We have reasonable suspicion that someone has used the data as a list of live email addresses, and sent spam to them. We have no evidence that any password hashes have been broken, or LibraryThing accounts compromised.

How passwords work:

• Systems like LibraryThing do not store passwords per se. Rather, we store complicated cryptographic transformations, called hashes, which are “salted” for increased security.
• In theory, you cannot get from the hash to the password. In practice, hackers with powerful computers can break hashed passwords, especially if the underlying password is simple (e.g., “book” rather than “mypencilbreaks71″ or “xyA1!oG3g”).
• Hacked passwords are dangerous when someone uses the same password across multiple online services, so failure at any one service opens up the rest.
• Members should change their password at LibraryThing and any other service on which they used the same password. Here and elsewhere, members should also choose longer, hard-to-guess passwords. We encourage you to read safe-password advice from Google or Twitter.

Security improvements:

We can’t go into detail about security improvements. (If we did, we’d be compromising security.) But we can say what you can see:

• We have moved our WordPress blogs off LibraryThing servers entirely, and onto a separate subdomain, blog.librarything.com. This insulates us from potential WordPress problems.
• We have upgraded our password system to the highest industry standards. Users who joined in the last week or so, or changed their passwords, are already on the new system. But for simplicity’s sake, we’re requiring everyone to change their password.
• We have a new system for password resets and changes, including password-strength indicators.
• Our password recovery system has been changed from one involving sending out a temporary password to one employing quick-expiring tokens.
• We are now sending out emails whenever a password has been changed. When a member changes their email address, change notices go out to both the new and old email addresses.
• To discourage spamming of public emails—something that happened recently to some members—we have added an option to show your public email to friends, to signed-in members or everyone. By default, everyone who formerly chose to display their email publicly will now be set to friends-only.

Free accounts:

• All members with accounts opened before November 20th, 2011 have been upgraded to lifetime accounts.