Expedia's TripAdvisor Member Data Stolen in Possible SQL Injection Attack

TripAdvisor discovered a data breach in its systems that allowed attackers to grab a portion of the Website's membership list from its database.

The data breach was discovered over the weekend of March 19, and an "unauthorized third party" stole the e-mail list, Steve Kaufer, co-founder and CEO of TripAdvisor, wrote in an email to members on March 24. The vulnerability has been shut down, and the company is working with law enforcement as well as conducting its own investigation, he said.

TripAdvisor does not collect or store members' credit card or financial information, and member passwords were not stolen, Kaufer said. He said most members won't notice anything as the result of the breach, although some users may receive some spam. The company notified the customers because "it's the right thing to do," he said.

"As a TripAdvisor member, I would want to know," Kaufer said.

If it is true that no passwords were compromised, it is "good news," according to Randy Abrams, director of technical education at ESET's Cyber Threat Analysis Center. "You have to give them credit for getting that part of the security right," Abrams said.

It is not clear at this point when the actual breach and theft occurred, according to TripAdvisor's FAQ page for the incident. However, TripAdvisor will be implementing additional security precautions to prevent another incident, the company promised.

It is also unclear how many users of the 20 million subscribed customers have been affected.

"99.9999% is a portion. 1% is also a portion," said Abrams, noting that the vagueness of the CEO's email makes it seem likely that it was a significant portion. There is also a difference between saying "many users will be unaffected" as opposed to "most users will not be affected," he said.

The "unspecified vulnerability" was likely exploited by a SQL injection attack, Victor Pinenkov, vice president of engineering at Mykonos Software, told eWEEK. Attackers likely entered SQL statements into several input fields on the TripAdvisor site, which when the page was submitted, were sent to the database, Pinenkov said. The database, not realizing it was an illegal request, ran the command and returned the result. The attacker may have just received the data dump right on the page, or used a debug proxy on the computer to intercept the HTTP response from the database, he said.

This sort of data breach is very common across many industries, said Kaufer.

SQL injection is still the No. 1 attack vector, Josh Shaul, CTO of Application Security, told eWEEK. While sometimes the attacks can result from carelessness on the part of the programmer who built the target Website, for the most part, attackers are getting more sophisticated, he said. "SQL injection attacks will continue to be a primary attack vector because they lead an attacker directly to their target, the database," he said.

It is possible that, with the email addresses in hand, attackers will be spamming affected TripAdvisor members. The company also noted the possibility of targeted phishing attacks, where the emails would ask users for more personal information such as credit card information, bank account information, passwords and ID numbers.

Attackers cam also refer to a list of frequently used passwords and then work through the email list to see if any of these TripAdvisor customers use the same weak passwords on other online accounts, including Facebook, Twitter and e-commerce sites, Shaul said.

Since the members are all from TripAdvisor's database, it is likely that the phishing attacks may somehow reference TripAdvisor, such as a security warning asking users to log in to protect and check their account or to click on a link to "reset" the password for security purposes. Spam messages may even claim special advertising offers exclusive to TripAdvisor members. TripAdvisor warned users to be on the lookout for unexpected messages, mail with misspelling or grammatical errors, or "alarmist" emails.

TripAdvisor will never ask for passwords or sensitive information over email, the company said.

Even though TripAdvisor is based in the United States, its client base is international.