Anonymous, the hacking group, claimed Sunday to have stolen thousands of credit card numbers and other personal information belonging to clients of U.S.-based security think tank Stratfor.

According to one hacker, the Anonymous’ goal was to pilfer funds from individuals’ accounts to give away as Christmas donations, and some victims confirmed unauthorized transactions linked to their credit cards.

Anonymous boasted of stealing Stratfor’s confidential client list, which includes entities ranging from Apple Inc. to the U.S. Air Force to the Miami Police Department, and mining it for more than 4,000 credit card numbers, passwords and home addresses.

Austin, Texas-based Stratfor provides political, economic and military analysis to help clients reduce risk, according to a description on its YouTube page.

The company charges subscribers for its reports and analysis, delivered through the web, emails and videos.

Stratfor’s main website was down, with a banner saying the “site is currently undergoing maintenance”.

Anonymous claimed Sunday to have stolen thousands of credit card numbers belonging to clients of Stratfor

Proprietary information about the companies and government agencies that subscribe to Stratfor’s newsletters did not appear to be at any significant risk, however, with the main threat posed to individual employees who had subscribed.

“Not so private and secret anymore?” Anonymous taunted in a message on Twitter, promising that the attack on Stratfor was just the beginning of a Christmas-inspired assault on a long list of targets.

Anonymous said the client list it had already posted was a small slice of the 200 gigabytes worth of plunder it stole from Stratfor and promised more leaks.

The hacking group said it was able to get the credit card details in part because Stratfor didn’t bother encrypting them – an easy-to-avoid blunder which, if true, would be a major embarrassment for any security-related company.

According to Fred Burton, Stratfor’s vice president of intelligence, the company had reported the intrusion to law enforcement and was working with them on the investigation.

“Stratfor has protections in place meant to prevent such attacks,” he said.

“But I think the hackers live in this kind of world where once they fixate on you or try to attack you it’s extraordinarily difficult to defend against.”

Hours after publishing what it claimed was Stratfor’s client list, Anonymous tweeted a link to encrypted files online with names, phone numbers, emails, addresses and credit card account details.

“Not as many as you expected? Worry not, fellow pirates and robin hoods. These are just the <<A’s>>,” read a message posted online that encouraged readers to download a file of the hacked information.

The attack is “just another in a massive string of breaches we’ve seen this year and in years past,” said Josh Shaul, chief technology officer of Application Security Inc., a New York-based provider of database security software.

Still, companies that shared secret information with Stratfor in order to obtain threat assessments might worry that the information is among the 200 gigabytes of data that Anonymous claims to have stolen, Josh Shaul said.

“If an attacker is walking away with that much email, there might be some very juicy bits of information that they have,” he added.

Lt. Col. John Dorrian, public affairs officer for the Air Force, said that “for obvious reasons” the Air Force doesn’t discuss specific vulnerabilities, threats or responses to them.

“The Air Force will continue to monitor the situation and, as always, take appropriate action as necessary to protect Air Force networks and information,” John Dorrian said in an email.

Miami Police Department spokesman Sgt. Freddie Cruz Jr. said that he could not confirm that the agency was a client of Stratfor, and he said he had not received any information about a security breach involving the police department.

Anonymous also linked to images online that it suggested were receipts for charitable donations made by the group manipulating the credit card data it stole.

“Thank you! Defense Intelligence Agency,” read the text above one image that appeared to show a transaction summary indicating that an agency employee’s information was used to donate $250 to a non-profit.

One receipt – to the American Red Cross – had Allen Barr’s name on it.

Allen Barr from Austin, Texas, recently retired from the Texas Department of Banking and said he discovered last Friday that a total of $700 had been spent from his account.

The man, who has spent more than a decade dealing with cybercrime at banks, said five transactions were made in total.

“It was all charities, the Red Cross, CARE, Save the Children. So when the credit card company called my wife she wasn’t sure whether I was just donating,” said Allen Barr, who wasn’t aware until a reporter with the AP called that his information had been compromised when Stratfor’s computers were hacked.

“It made me feel terrible. It made my wife feel terrible. We had to close the account.”

Wishing everyone a “Merry LulzXMas” – a nod to its spinoff hacking group Lulz Security – Anonymous also posted a link on Twitter to a site containing the email, phone number and credit number of a U.S. Homeland Security employee.

The employee, Cody Sultenfuss, said he had no warning before his details were posted.

“They took money I did not have,” Cody Sultenfuss told The Associated Press in a series of emails, which did not specify the amount taken.

“I think <<Why me?>> I am not rich.”

But the breach doesn’t necessarily pose a risk to owners of the credit cards. A card user who suspects fraudulent activity on his or her card can contact the credit card company to dispute the charge.

Stratfor said in an email to members that it had suspended its servers and email after learning that its website had been hacked.

“We have reason to believe that the names of our corporate subscribers have been posted on other web sites,” said the email, signed by Stratfor Chief Executive George Friedman and passed on to AP by subscribers.

“We are diligently investigating the extent to which subscriber information may have been obtained.”

“Stratfor’s relationship with its members and, in particular, the confidentiality of their subscriber information, are very important to Stratfor and me,” George Friedman wrote.

One member of the hacking group, who uses the handle AnonymousAbu on Twitter, claimed that more than 90,000 credit cards from law enforcement, the intelligence community and journalists – “corporate/exec accounts of people like Fox News” – had been hacked and used to “steal a million dollars” and make donations.

It was impossible to verify where credit card details were used. Fox News was not on the excerpted list of Stratfor members posted online, but other media organizations including MSNBC and Al-Jazeera English appeared in the file.

Anonymous warned it has “enough targets lined up to extend the fun fun fun of LulzXmas through the entire next week”.

Anonymous has previously claimed responsibility for attacks on credit card companies Visa Inc. and MasterCard Inc., eBay Inc.’s PayPal, as well as other groups in the music industry and the Church of Scientology.