The global security firm Sophos said in a blog post that it had begun noticing the new Windows ransomware on 18 March as it took aim at Exchange boxes that still had not been patched to fix the ProxyLogon vulnerabilities disclosed by Microsoft on 3 March.
Black Kingdom ransomware is by far the worst I’ve ever seen. It doesn’t exclude exe, dll, or sys files so in cases bricks the system. It doesn’t track if it’s been run previously, so every victim I’ve seen has been recursively encrypted at least 4 times. And it’s coded in python.
— MalwareTech (@MalwareTechBlog) March 24, 2021
Mark Loman, a director of Engineering for Next-Gen Technologies at Sophos, said the new ransomware did not have the most sophisticated of payloads.
"In fact, our early analysis reveals that it is somewhat rudimentary and amateurish in its composition, but it can still cause a great deal of damage," he said.
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Loman said Sophos researchers had found the origin of Black Kingdom was a remote server geolocated to Germany, while the attacker's IP also came from the same country. But as both addresses belong to a Tor exit node, he said the physical location of the attacker could not be pinpointed.
His blog post, to which Sophos' Vikas Singh, Alex Vermaning and Gabor Szappanos also contributed, included detailed technical analysis of how Black Kingdom worked.
"It's been three weeks since the release of security patches for the ProxyLogon vulnerabilities, and adversaries are racing against time to target still unpatched Exchange servers," Loman said.
BlackKingdom ransomware on my personal servers. It does indeed encrypt files. They exclude c:\windows, however my storage drivers were in a different folder and it encrypted those... meaning the server doesn't boot any more. If you're reading BlackKingdom, exclude *.sys files pic.twitter.com/nUVUJTbcGO
— Kevin Beaumont (@GossiTheDog) March 23, 2021
"As we saw with DearCry ransomware, this can lead to the release of prototype, rushed or poor quality code created by less experienced developers. Today we report on another example of this, perpetrated by the operators behind Black Kingdom ransomware.
"The Black Kingdom ransomware targeting unpatched Exchange servers has all the hallmarks of being created by a motivated script-kiddie. The encryption tools and techniques are imperfect but the ransom of $10,000 in bitcoin is low enough to be successful. Every threat should be taken seriously, even seemingly low-quality ones.
"Defenders should take urgent steps to install Microsoft's patches to prevent exploitation of their Exchange Server. In addition, the Exchange server should be scanned for web shells that allow attackers run commands on the server. If this is not possible, the server should be disconnected from the internet or closely monitored by a threat response team."
Meanwhile, British security boffin Kevin Beaumont posted a tweet showing the ransom note from the new ransomware on one of his personal servers that functions as a honeypot.
"Black Kingdom ransomware on my personal servers. It does indeed encrypt files. They exclude c:\windows. However my storage drivers were in a different folder and it encrypted those... meaning the server doesn't boot any more. If you're reading Black Kingdom, exclude *.sys files," he said.
