AP Twitter Hack: Lessons Learned

Anonymous: 10 Things We Have Learned In 2013

Would you trust an email that says: "Please read the following article, it's very important: www.washinqtonpost.com/blogs/worldviews/wp/2013/04/23/"?

So went a phishing email reportedly sent to multiple employees at the Associated Press, less than an hour before the company's Twitter feed was taken over and used to issue multiple tweets, including a hoax report that President Obama had been injured by explosions at the White House. Cue a temporary stock market tumble.

Sharp-eyed email recipients who weren't distracted might have noticed that Washington was misspelled in the link. But every other indicator suggested it was from a fellow AP staffer, down to the sender's email address, and the name and mobile phone number listed at the bottom of the email.

[ How is Twitter protecting itself against attacks? Twitter Preps Two Factor Authentication After AP Hoax. ]

Reporter Mike Baker at AP said via Twitter that the phishing email had been "impressively disguised." That gets to the heart of why it's so difficult to block spear-phishing attacks, which have taken down the likes of security firm RSA and media giant The New York Times: They're incredibly cheap and easy to develop and launch, and attackers only need one recipient to click a link and follow through to potentially compromise first one PC, and then an entire network.

The follow-through in this case was to a phishing website -- most likely built to resemble an actual Washington Post blog page -- that asked the user to enter his username and password. It might have even purported to allow them to use their Twitter credentials to log in. If the user shared her credentials, that data would be passed onto attackers, who would then be able to log in as that person to any website for which the target had reused the same password.

How can businesses prevent an AP-style Twitter account hijacking? The short answer is that it's very difficult for users to spot every phishing attempt, and also difficult to adequately protect Twitter accounts against hijackings, whether you're an individual or a business. For starters, that's because only a username and password are required to log into a Twitter account, and the username is already publicly known, because it's a user's Twitter handle.

"The username is an issue," said Sean Sullivan, security advisor at F-Secure Labs, speaking by phone. "Consider your online banking. My bank issued me a unique customer number and I don't share that with anybody. So both the username and the password are secret. But with social media/networking sites, half of the secrecy is gone."

Another issue is a lack of administrator accounts. Currently, a single Twitter account such as @AP has only a single password. Accordingly, whoever needs to have access to the account must be told the password, and the more copies of the password that proliferate, the greater the likelihood that the password will be recorded in multiple places, which makes it a target for data-exfiltration malware.

Twitter is reportedly testing a two-factor authentication system for users, but this will be no security panacea, especially for business users. "Two-factor systems are great for me as an individual, but for accounts that have 10 users, maybe because they're working on shifts around the clock, like AP, it just doesn't scale," Sullivan said.

Furthermore, two-factor systems can be defeated via password-reset systems, at least some of the time. That's because if a user loses the smartphone to which a one-time code gets sent via SMS, or that contains their authentication app, they need to have another way to get into their account. Accordingly, many users add a backup email account in Twitter, to which a one-time password can be sent via Twitter's password-reset screen.

If so, then an attacker who first compromises that email account can then simply request to reset a password for the linked account, and he will receive a working one-time password to the email account he's compromised. In addition, Twitter allows people to search for people's Twitter usernames based on their email address, thus giving would-be attackers a tool for sniffing out which email is likely tied to a target's account.

"So they enable you to search for accounts with an email address, but then they consider it to be personal information for a password challenge. That's just circular," said Sullivan. "That may have been fine when this was personal accounts for fun, five years ago. But it really doesn't scale for AP feeds that Wall Street algorithms are tuned to monitor."