Security researchers observed a new strain of ransomware called “PwndLocker” targeting the networks of enterprises and U.S. cities.

Sources told Bleeping Computer that PwndLocker ransomware started up in late 2019, infecting several U.S. cities and organizations in the months that followed. Those victims included Lasalle County in Illinois, a government body from which the threat demanded a ransom of 50 bitcoins (worth approximately $442,000 at the time of Bleeping Computer’s report) for a decryption key, and the city of Novi Sad in Serbia.

According to Bleeping Computer’s sources, the threat’s ransom amounts ranged from $175,000 to over $660,000 depending on the site of the network at the time of their analysis.

The computer self-help site analyzed a sample of the ransomware and found that it used the “net stop” command to disable a variety of Windows services, security solutions, backup applications and other programs. This technique allowed PwndLocker to complete its encryption routine unhindered. At that point, it dropped a ransom note onto the infected machine that told victims to contact an email address or visit a Tor site for payment instructions.

Not the First Ransomware to Target Entire Networks

PwndLocker ransomware isn’t the first crypto-malware family to set its sights on encrypting entire networks. In March 2019, Bleeping Computer observed the Clop variant of the Cryptomix ransomware family targeting organizations’ networks instead of their workstations. Less than a year later in January 2020, researchers spotted the Ako ransomware going after organizations’ networks. Shortly thereafter, Bleeping Computer witnessed SNAKE ransomware going after entire networks and all the devices connected to them.

How to Defend Against PwndLocker Ransomware

Security professionals can help their organizations defend against a PwndLocker ransomware infection by creating a solid backup strategy. This plan should involve the creation and ongoing testing of multiple backup measures as part of a larger data protection program. Infosec personnel should also consider investing in a single integrated solution that combines encryption, identity and access management (IAM), key management and other security controls.