A foreign team of hackers who have been carrying out cyberattacks against Russia has received thanks from the Ukrainian military, the BBC reports.

The One Fist team stole data from Russian military firms and hacked cameras to spy on the aggressor. Christopher Cortright, 53, a resident of Michigan, USA, who coordinated the hacking attacks from his home, received the award.

One Fist is made up of hackers in eight different countries, including the UK, the US, and Poland. Together they have carried out dozens of cyberattacks, celebrating each one on social media. All of them received certificates of appreciation from the Ukrainian military for their “a significant contribution to the development and maintenance of vital activities of the military.”

Most recently, the One Fist team successfully hacked into the system of a well-known Russian arms manufacturer and stole 100 gigabytes of private data.

“The array of information transferred to the Ministry of Defence of Ukraine contains drawings, specifications, patents, software referring to both existing and promising military developments,” One Fist says in a statement.

Ukraine added that the stolen data was a significant blow to Moscow and is estimated at $1.5 billion.

The full-scale war in Ukraine has caused a surge in cyber activity. Groups such as Anonymous targeted Russia with disruptive and low-level hacking attacks, which Russia largely ignored.