The U.S. Department of Justice gave the FBI permission to access hundreds of computers across the nation to remove damaging back door access from Microsoft Exchange Servers. These “web shells” were left by hackers who had previously invaded the systems.
The Privacy Issue
Some citizens may be surprised by this move, fearing that it violates privacy and security for those computers. However, the government justified the action by claiming that it must utilize its power to protect those who are unable or unwilling to update their systems and fix vulnerabilities.
The FBI’s intention is to eliminate any further damage done by this high-level hacking operation. If left untreated, it could progress to epidemic proportions affecting other devices and machines critical to the infrastructure of the country.
What is Happening and Why?
The announcement posted yesterday read, “The Justice Department today announced a court-authorized operation to copy and remove malicious web shells from hundreds of vulnerable computers in the United States running on-premises versions of Microsoft Exchange Server software used to provide enterprise-level e-mail service.”
They explained more about the incident, “Through January and February 2021, certain hacking groups exploited zero-day vulnerabilities in Microsoft Exchange Server software to access e-mail accounts and place web shells (which are pieces of code or scripts that enable remote administration) for continued access. Other hacking groups followed suit starting in early March after the vulnerability and patch were publicized. Although many infected system owners successfully removed the web shells from thousands of computers, others appeared unable to do so, and hundreds of such web shells persisted unmitigated. Today’s operation removed one early hacking group’s remaining web shells, which could have been used to maintain and escalate persistent, unauthorized access to U.S. networks. The FBI conducted the removal by issuing a command through the web shell to the server, which was designed to cause the server to delete only the web shell (identified by its unique file path).”
The servers are located in the areas of the Southern District of Texas, District of Massachusetts, Northern District of Illinois, and Northern District of Virginia.
How Did They Do It?
The notice said that
“The FBI conducted the removal by issuing a command through the web shell to the server, which was designed to cause the server to delete only the web shell (identified by its unique file path).”
However, the FBI did not patch anything or remove any malware. They simply removed the ability for hackers to contact and control the machine remotely. More cleanup will be necessary for the systems to be restored back to safe and proper working conditions.
The FBI also gathered evidence, including stolen/used passwords while connected to the machines. The notice pre-warned of this with “FBI personnel will access the web shells, enter passwords, make an evidentiary copy of the web shell, and then issue a command through each.”
The Bottom Line
During the earlier part of this year, multiple hacking groups exploited these vulnerabilities more than once. The FBI’s proactive approach is aimed at reducing risk and protecting the American people as a whole. The U.S. government has discovered that a Chinese hacking group affected tens of thousands of servers using these exploits.
Assistant Attorney General John C. Demers said, “Today’s court-authorized removal of the malicious web shells demonstrates the Department’s commitment to disrupt hacking activity using all of our legal tools, not just prosecutions.” He also commented on the cooperation between the government and the private sector to facilitate retaliation against the upheaval of attacks since 2020.
The Justice Department said this fix is unrelated to Microsoft’s patch coming out tomorrow (April 13, 2021).