A federal district court in Virginia has ruled that the FBI has the right to hack into computers around the world without getting a local warrant, and without any review by courts.

The ruling, by US District Judge Henry Morgan, comes during the prosecution of Edward Matish.

Matish is one of the 100-plus suspects arrested after the FBI took over the Playpen child abuse website and used it to infect visitors with a "network investigative technique" (NIT). This revealed their IP addresses and details of the computers they were using.

Other attempts to prosecute Playpen cases has led to problems, with some courts finding that because the FBI only got a single warrant to cover all NIT infections, the search warrants were invalid. Not so Judge Morgan, who said a local warrant wasn't needed and IP addresses couldn’t be considered protected.

"The court finds that Defendant possessed no reasonable expectation of privacy in his computer's IP address, so the Government's acquisition of the IP address did not represent a prohibited Fourth Amendment search," the ruling reads.

"Even an Internet user who employs the Tor network in an attempt to mask his or her IP address lacks a reasonable expectation of privacy in his or her IP address."

The judge also denied the defendant's counsel the opportunity to examine the NIT to see if it performed as claimed. He said it was subject to "law enforcement privilege," and wasn't relevant to the defence in this case.

"This case embodies the fundamental collision between the duty of our Government to protect its citizens from the dangers caused by child pornography with the implied right of privacy under the Fourth Amendment," he wrote.

"Notably, the Government already has found that protecting its citizens outweighs the First Amendment's right of freedom of speech, for it applies prior restraint to child pornography."

The ruling is expected to be appealed but Mark Rumold, a senior staff attorney Electronic Frontier Foundation, slammed it as setting a very dangerous precedent and called it "dangerously flawed".

"The implications for the decision, if upheld, are staggering: law enforcement would be free to remotely search and seize information from your computer, without a warrant, without probable cause, or without any suspicion at all," he said.

"To say the least, the decision is bad news for privacy. But it's also incorrect as a matter of law, and we expect there is little chance it would hold up on appeal." ®