US hospital pays ransom to hackers

Paying hackers a $US17,000 ransom was "the quickest and most efficient way" to rescue a hospital's computer network, its chief executive says.

File image. Source: AAP

A Los Angeles hospital paid a $US17,000 ($A23,715) ransom to hackers because paying was the quickest and most efficient way to solve the problem, the medical centre's chief executive says.

Hollywood Presbyterian Medical Center paid the demanded ransom of 40 bitcoins - currently worth about $US16,660 - after the network infiltration that began February 5, chief executive Allen Stefanek said in a statement on Wednesday.

The FBI is investigating the attack, often called "ransomware", where hackers encrypt a computer network's data to hold it hostage, providing a digital decryption key to unlock it for a price.

"The quickest and most efficient way to restore our systems and administrative functions was to pay the ransom and obtain the decryption key," Stefanek said.

"In the best interest of restoring normal operations, we did this."

Workers at Hollywood Presbyterian noticed the network problems on February 5, and it became clear there was a malware infiltration that was disabling the network.

Computer experts and law enforcement were immediately informed, Stefanek said.

On Monday, 10 days after the attack, the network was in full operation again.

Patient care was not affected by the hacking, and there is no evidence any patient data was compromised, Stefanek said.

Computer security experts usually recommend people not pay the ransom to hackers, though at times law enforcement agencies suggest they do, said Adam Kujawa, the head of malware intelligence for Malwarebytes, a San Jose-based company that recently released anti-ransomware software.

Bitcoins, the online currency that is hard to trace, is becoming the preferred way for hackers collect a ransom, FBI Special Agent Thomas Grasso, who is part of the government's efforts to fight malicious software including ransomware, told the Associated Press in 2015.

In 2013, the number of attacks each month rose from 100,000 in January to 600,000 in December, according to a 2014 report by Symantec, the maker of antivirus software.

A report from Intel Corp's McAfee Labs released in November said the number of ransomware attacks is expected to grow even more in 2016 because of increased sophistication in the software used to do it.