Tens of thousands of poorly configured MongoDB databases have been compromised over the past week, with attackers wiping data and demanding up to one bitcoin to return it.
Victor Gevers, from Netherlands-based GDI Foundation, and Niall Merrigan, a Norway-based developer, have been tracking a surge in attacks on MongoDB installations in which a handful of groups are wiping vulnerable databases and replacing them with an empty database with names such as a 'WARNING', 'PWNED', and 'PLEASE_READ'.
The attackers claim to hold a copy that can be purchased for between 0.2BTC and 1BTC, but there's no guarantee the data is actually available if a payment is made.
MongoDB is a popular open-source NoSQL database, widely used for big data and analytics. On the DB-Engines Ranking of database popularity it stands in fourth spot out of 315 systems, behind only Oracle, MySQL, and Microsoft SQL Server.
At the current count, more than a quarter of the 99,000 MongoDB instances open to the internet have been compromised.
The ransom attackers are targeting low-hanging fruit, namely MongoDB instances that don't have password-protected admin accounts.
The sudden spike in attacks may be attributed to copycat groups jostling for a slice of the action. The first recorded attacks occurred in mid-December with payments appearing to have been made to someone using the name, Harak1r1.
Now there are over a dozen groups using their own email address and bitcoin wallets, according to a spreadsheet maintained by Gevers and Merrigan. The most active attacker, Kraken0, has compromised 15,482 databases and is demanding 1BTC to return the wiped data.
The two researchers say they have assisted more than 100 organizations whose database have been hit by ransom attackers.
Merrigan told Bleeping Computer the MongoDB attacks were a "gold rush", with different groups replacing each others' ransom notes.
MongoDB's director of product security, Andreas Nilsson, has published a list of actions admins can use to prevent the attacks. As with most ransomware attacks, Nilsson stressed the importance of backing up data.
"If you take regular backups of the compromised database, you can restore the most recent backup... If you don't have a backup or are otherwise unable to restore the data, unfortunately your data may be permanently lost," he wrote.
"You should assume that the attacker has a copy of all data from the affected database," he added.