A ransomware gang split the work between a person and an AI agent to hit a UK school estate

A UK school estate was compromised by an affiliate of the 3AM ransomware group in what the security firm Bitdefender calls a hybrid human and AI operation, Infosecurity Magazine reported on 4 November. The incident ran from 10 to 19 September 2026 and ended with the attackers encrypting 37 machines. Bitdefender described it as "the first case of this kind that we have documented in Europe."

How it started: the backups

Bitdefender could not determine how the attackers first got in. The first activity it recorded was on 10 September, when the attackers accessed credentials stored on the estate's backup infrastructure and decrypted them. On 14 September they ran the credential dumping tool Mimikatz, created two backdoor domain administrator accounts by separate routes, and copied 40 finance related files out to their own server.

Where the AI came in

The researchers looked at the timing of commands. During one stretch of retries, each new attempt came between 40 and 101 seconds after the last, whether the change was small or a complete rewrite, which Bitdefender says points to an AI agent writing the commands. Moving on to a new task took minutes, and other commands came two to 16 minutes apart, the pace of a person reading the output and deciding what to do next. The clearest example, Bitdefender says, came on 19 September, when the attackers linked three separate Active Directory domains with two way trusts and spread the backdoor account's access across the estate within about three hours, reaching 50 machines. They then tried to remove endpoint detection and response tools before encrypting 37 of them.

Nothing new, just faster

Bitdefender notes that the methods themselves are typical of ransomware: stolen backup credentials, rogue domain administrators, trusts between domains and legitimate built in tools. "The approach looks pragmatic: the model takes the mechanical, repetitive work, and nothing in it needed skill or spend that these attackers did not already have," the researchers wrote. They expect hybrid attacks like this to become more common in 2027.

What Bitdefender recommends

Bitdefender's recommendations for defenders are to keep the administrative accounts of separate domains separate and never keep privileged credentials for several domains in one place; to treat backup infrastructure as a target and review the backup strategy with malicious intent in mind; to restrict remote execution and administrative shares; to block interpreters and shells on machines that never use them; and to put an endpoint agent on every machine.