In an unprecedented move, the FBI used hacker tools to hack into hundreds of infected computers in an attempt to protect them.
The violation, which affected tens of thousands of clients of Microsoft Exchange Server worldwide, reportedly left behind a number of backdoors that could allow any hacker to re-enter these systems. The FBI exploited it by using these same web shells / backdoors to delete them remotely, an operation that the agency says was successful.
"The FBI carried out the removal by issuing a web shell command on the server, which was designed to cause the server to delete the web shell on its own," the Justice Department said in a statement.
The strange thing is that the owners of these Microsoft Exchange Servers probably do not yet know about the involvement of the FBI. The Justice Department said it was simply "trying to warn" some landlords who could help.
All of this was done with the full approval of the Texas court, and you can read the search and seizure warrant from here.
It will be interesting to see if this move loses precedent for future responses to large hacks.
Of course it makes me wonder how many owners are angry and how grateful the FBI is.
The FBI says thousands of systems were repaired by their owners before remote backdoor removal began and removed only "web shells that could have been used to maintain and scale up unauthorized access to U.S. networks."
"Today's court-ordered removal of malicious web shells demonstrates the Department's commitment to end all piracy using all legal tools, not just prosecution," said a statement from Assistant Attorney General John C. Demers of the Department of Homeland Security. Security of the Ministry of Justice. .
Today is Patch Tuesday, by the way, and Microsoft security update in April 2021 includes new fixes for Exchange Server vulnerabilities.