Citigroup Credit Card Portal Breach Compromises 200,000 Customers

Approximately 200,000 customers had their credit card details compromised after hackers breached Citi Account Online back in May.

Cyber-attackers have breached financial giant Citigroup's Web portal and gained access to customer credit card information. The company said the most sensitive information remained safe.

The perpetrators broke into Citi Account Online and viewed customer names, account numbers and some contact information such as email addresses, Citigroup said in a statement June 9. Social Security numbers, birth dates, card expiration dates and the security codes generally found on the back of the credit cards were not compromised as they are stored elsewhere.

Citi Account Online is a Web portal which maintains basic customer information.

Even though Citibank issues more than 150 million cards globally, Citigroup claimed the breach was localized to only North American customers. About 1 percent of its 21 million credit card customers in North America, or 200,000 customers, were compromised, according to Citigroup.

While 200,000 sounds "kind of small" when compared to what happened in recent breaches, such Sony's 100 million, the number of records compromised is "not the important thing here," Anup Ghosh, founder and chief scientist of Invincea told eWEEK. "It's the loss of faith in the institution's ability to protect us," Ghosh said.

Financial institutions are "principal" targets for cyber-criminals, according to Brendan Hannigan, CEO of Q1 Labs. "Security trust means more than just making sure you're in compliance with regulations," Hannigan told eWEEK.

Citi discovered the hacking incidents in early May during routine monitoring, according to The Financial Times, which broke the story June 9. Citigroup likely had spent the time trying to "quantify what was touched and what had happened," Ghosh said.

Citi is getting in touch with affected customers and will be establishing "enhanced procedures" to prevent future intrusions, said Sean Kevelighan, a spokesman for Citi's North America Consumer Banking division. Law enforcement officials have also been notified.

"For the security of these customers, we are not disclosing further details," Kevelighan said, declining to elaborate on how the attack occurred.

The Financial Times reported that several card customers originally found out when their credit card transactions were denied. Several people said their debit cards were compromised, according to the news story.

"For the actual breach to happen at a bank is a very big deal," Avivah Litan, an analyst with Gartner Research, told the Financial Times.

Citigroup global enterprise payments head Paul Galant, who previously ran the bank's credit card unit, told Reuters in April that security breaches are a fact of life for financial institutions. However, companies need to be "thinking like hackers do," Mark Hatton, president and CEO of Core Security, told eWEEK, noting that deploying defensive technologies and hoping they keep the bad guys out is "clearly not working."

Businesse are relying on defense mechanisms that were "developed in the last century" and have not changed since then, while attackers are creating new threats and "evolving every day," said Ghosh.

Even though the stolen information is incomplete, there's enough for scammers to use it in a phishing attack to trick victims in revealing more sensitive pieces, Ghosh said. This is not a problem that can be fixed by training, since even if users are taught not to click on links from unknown senders, it's not reasonable to expect them to differentiate spear phishing attacks where the sender is trusted, such as their bank or employer, according to Ghosh.

Phishing can also be done over the phone, with the caller pretending to be from the institution trying to verify security details, as happened shortly after the data breach in Texas back in March.

Customers should be leery of any communications, email or phone calls purporting to be from financial institutions, according to Chester Wisniewski, senior security adviser at Sophos. Instead of clicking on the links in the email to get to the financial institution's Web page or calling the phone number provided, customers should follow up by directly calling the phone numbers published on the credit cards or on the statements, Wisniewski said.