Yahoo security breach shocks experts

A Yahoo security breach that exposed 450,000 usernames and passwords from a site on the huge web portal indicates that the company failed to take even basic precautions to protect the data.

Security experts are befuddled as to why a company as large as Yahoo would fail to cryptographically store the passwords in its database. Instead, they were left in plain text, which means a hacker could easily read them.

"It is definitely poor security," Marcus Carey, a security researcher at Rapid7, said. "It's not even security 101. It's basic application development 101."

Yahoo declined a request for an interview, and only emailed a statement confirming the breach that occurred on Wednesday. The company said that an "older file" containing roughly 450,000 user names and passwords was stolen from its Contributor Network, a subset of Yahoo's massive network of Web sites.

Membership in the Contributor Network consists of freelance journalists who write content for Yahoo Voices. The network was established following Yahoo's 2010 acquisition of Associated Content.

Less than 5 percent of the stolen data had valid passwords, Yahoo said. "We are taking immediate action by fixing the vulnerability that led to the disclosure of this data, changing the passwords of the affected Yahoo! users and notifying the companies whose users accounts may have been compromised," the statement said.

The breach had ramifications far beyond Yahoo, because the portal allowed people registering with the Contributor Network to use credentials from other sites to log in. Carey identified some of the other sites as Google's Gmail, Microsoft's Hotmail, AOL, Comcast and Verizon.

A hacker group called D33Ds Company took credit for the breach, and posted a statement on its website saying the attack was a warning. "We hope that the parties responsible for managing the security of this subdomain will take this as a wake-up call, and not as a threat," the group said, according to media reports. "There have been many security holes exploited in Web servers belonging to Yahoo! Inc. that have caused far greater damage than our disclosure. Please do not take them lightly."

The hackers claimed to use a common attack method called a SQL injection to access the database that fed the server hosting the site. A SQL injection typically involves sending commands through a search field or a URL to break into a poorly secured site.

Tony Perez, chief operating officer for Sucuri, who used to work with defense contractors in developing secure applications, said Yahoo's overall security lapses were a disservice to its users. "It makes you wonder. If a property like Yahoo at that scale is doing that, and they did it for their Yahoo Voices, what's the probability of that also occurring in their other properties?"

The Yahoo breach occurred a month after professional social networking site LinkedIn acknowledged that 6.5 million usernames and passwords were stolen and posted on a Russian hacker forum. In that case, the passwords had been stored using a cryptographic method called hashing.

Read more about malware/cybercrime in CSOonline's Malware/Cybercrime section.

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