UGNazi logo portraying kawaii Hitler, an Internet meme (UGNazi)

Cosmo, one of the inner circle of the shadowy UGNazi hacker collective recently busted by the FBI, has ridiculed claims that a vigilante hacker was behind their downfall.

The grey-hat hacker 'the Jester', whose public accounts were recently breached by Anonymous in a revenge attack, had nothing to do with his arrest or that of prominent UGNazi members, Cosmo told the IBTimes UK, in an exclusive interview.

'Cosmo', a teenager lives in the Los Angeles area, was arrested in May in connection with the hack of a British web billing firm WHMCS, which resulted in the leaking of a 1.7 gigabyte trove of data, including 500,000 users' accounts, with some number of credit card details made available online.

According to Cosmo: "The WHMCS leak was to set an example to not have hundreds of thousands of customer data on a third party server."

The company, which offers client management, billing and support solutions, admitted the breach, explaining that it was the result of a social engineering attack.

"The person was able to impersonate myself with our web hosting company, and provide correct answers to their verification questions," WHMCS founder Matt Pugh explained. "This means that there was no actual hacking of our server. They were ultimately given the access details."

The FBI arrested Cosmo again and searched his house on June 26. "I was in a juvenile detention centre for two days then released and given a court date set to July 25 at Long Beach Superior Court. I will appear to face trial."

His charges include identity theft, forgery, fraud and unauthorised access to a network or server. "I am not guilty of them," he commented.

After the arrest, renowned grey-hat hacker and self-proclaimed internet vigilante, the Jester took credit for helping the FBI.

A feud between him and the UGNazi developed after the hacktivists launched a DDoS attack on the site of the Wounded Warrior Project, set up to help thousands of US soldiers injured on active service. The Jester pledged to hunt down the collective. "Within 23 days of this date justice will be served," he said on June 7.

But Cosmo dismissed the possibility that the Jester could be behind the arrests. "No, he had nothing to do whatsoever with my arrest nor JoshTheGod's [aka Mir Islam, leader of the group, also charged with trafficking in stolen card numbers]," he told IBTimes UK.

In another interview, Cosmo said that the FBI were "laughing about Jester taking credit." The investigation started two years ago, with the FBI agents posing as hackers on Internet forums, prevented more than $200 million in losses on over 400,000 compromised consumer credit and debit cards, US authorities in New York said.

Cosmo confirmed that UGNazi was responsible for disabling Twitter for 40 minutes worldwide at the end of June.

"Yes, I and UGNazi was responsible for the Twitter outage a few weeks ago," he said.

Twitter denied that the service interruptions were caused by the hacking group, claiming it was a "cascading bug". "Like we stated on Twitter, when a company has a chance to deny something that can discredit them...they will do so," Cosmo commented, adding that the social networking company was targeted because of their support of the controversial Cyber Intelligence Sharing and Protection Act (Cispa).

The group claimed responsibility in the past for attacks on Visa, MGM and CIA. In one case, UGNazi took down the website of pizza company Papa John's with a DDoS attack, because the company "took 2 hours longer than expected to deliver my food".

The Jester was targeted by Anonymous, which attacked all the public accounts of the hacker and threatened to publish the content of emails and banking details.

However, Cosmo challenged the affiliation with the infamous hacking collective.

"I don't really support Anonymous, but they seem to support me and UGNazi," he said.