The Avaddon ransomware gang has shut down operation and released the decryption keys for their victims to BleepingComputer.com.

This morning, BleepingComputer received an anonymous tip pretending to be from the FBI that contained a password and a link to a password-protected ZIP file.

This file claimed to be the "Decryption Keys Ransomware Avaddon," and contained the three files shown below.

After sharing the files with Fabian Wosar of Emsisoft and Michael Gillespie of Coveware, they confirmed that the keys are legitimate.

Using a test decryptor shared with BleepingComputer by Emsisoft, I decrypted a virtual machine encrypted today with a recent sample of Avaddon.

In total, the threat actors sent us 2,934 decryption keys, where each key corresponds to a specific victim.

Emsisoft is working on a free decryptor with these keys, and it should be available within the next 24 hours, if not sooner.

While it doesn't happen often enough, ransomware groups have previously released decryption keys to BleepingComputer and other researchers as a gesture of goodwill when they shut down or release a new version.

In the past, decryption keys have been released for TeslaCrypt, Crysis, AES-NI, Shade, FilesLocker, Ziggy, and FonixLocker.

Avaddon shuts down ransomware operation

Avaddon launched its operation in June 2020 through a phishing campaign that contained a winking smiley, shown below.

Over time, Avaddon has grown into one of the larger ransomware operations, with the FBI and Australian law enforcement recently releasing advisories related to the group.

At this time, all of Avaddon's Tor sites are inaccessible, indicating that the ransomware operation has likely shut down.

Furthermore, ransomware negotiation firms and incident responders saw a mad rush by Avaddon over the past few days to finalize ransom payments from existing unpaid victims.

Coveware CEO Bill Siegel has told BleepingComputer that Avaddon's average ransom demand was around $600k.

However, over the past few days, Avaddon has been pressuring victims to pay and accepting the last counteroffer without any push back, which Siegel states is abnormal.

It is not clear why Avaddon shut down, but it was likely caused by the increased pressure and scrutiny by law enforcement and governments worldwide after recent attacks against critical infrastructure.

"The recent actions by law enforcement have made some threat actors nervous: this is the result. One down, and let’s hope some others go down too," Emsisoft threat analyst Brett Callow told BleepingComputer.

With the recent attacks against Colonial Pipeline and JBS, ransomware has become a priority of the US government.

As most of the larger ransomware operations are believed to be operated within Russia or other CIS countries, President Biden will be discussing these recent ransomware attacks with Russian President Vladimir Putin at the June 16 Geneva summit.