A hacking group that crippled South Korean banks, government websites and news agencies in early 2013 may be active again, Palo Alto Networks said Wednesday.

The firewall maker said it found strong similarities between malware used in a recent attack in Europe and that used in the South Korean attacks, referred to as Dark Seoul and Operation Troy.

The organization in Europe that was attacked was likely a victim of spear-phishing, where an email with a malware attachment or a harmful link is sent to hand-picked employees.

The malware had been wrapped into legitimate video player software that was hosted by an industrial control systems company, wrote Bryan Lee and Josh Grunzweig of Palo Alto in a blog post. The code appears to be the same as the malware used in the Dark Seoul attacks although without the destructive component that wipes hard drives.

"It is likely the same adversary group is involved, although there is currently insufficient data to confirm this conclusion," they wrote.

The Dark Seoul attacks on March 20, 2013 wiped data from bank computers, shut down ATMs and also took down government websites.

The malware was configured to wipe a computer's Master Boot Record (MBR), the first sector of a PC’s hard drive that the computer looks to before loading the operating system.

The same kind of wiper malware also wrecked thousands of computers at Sony Pictures Entertainment last year after gigabytes of data was stolen from its network. The U.S. government blamed the attack on North Korea.

In July 2013, security vendor McAfee published an analysis of Dark Seoul attacks, which it called Operation Troy. The report also described a much less noisy parallel operation that appeared to be aimed at stealing classified military data.

It initially appeared that two separate groups -- the Whois Hacking Team and the NewRomanic Cyber Army Team -- were behind the attacks. But McAfee concluded it was likely just one group, based on an analysis the attack code.

Palo Alto said the command-and-control servers for the most recent attack are compromised websites in South Korea and Europe that appear to be running out-of-date software.

It is challenging to develop new hacking tools and malware, and it's unlikely that the group behind Dark Seoul would have shared it with other actors, Palo Alto said.

"The similarities in tactics however, do seem to outweigh the differences, and it is highly likely this is the same group or groups responsible for the original Dark Seoul/Operation Troy attacks, but with a new target and a new campaign," Palo Alto wrote.