The FBI has warned hackers deployed the Mamba ransomware against several public and private organizations, but a flaw in the malware could allow companies to get their encrypted data back.
In an alert, the feds said hackers used the ransomware against local governments, public transportation agencies, legal services, technology services, and industrial, commercial, manufacturing and construction businesses.
Mamba encrypts data using DiskCryptor — an open source full-disk encryption software — to restrict victim access by encrypting an entire drive, including the operating system. While this software isn’t inherently malicious, the FBI warned hackers have weaponized it.
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Once data has been encrypted, the system displays a ransom note including the hacker’s email address, ransomware file name, the host system name, and a place to enter the decryption key.
However, the FBI noted that installing DiskCryptor requires a system restart to add essential drivers. The ransomware program restarts the system about two minutes after the installation to complete the driver installation. The encryption key and the shutdown time variable are saved to a configuration file (myConf.txt) and are readable until the second restart about two hours later, concluding the encryption and displays the ransom note.
“If any of the DiskCryptor files are detected, attempts should be made to determine if the myConf.txt is still accessible. If so, organizations can recover the password without paying the ransom. This opportunity is limited to the point in which the system reboots for the second time,” a statement from the FBI read.
The alert provided details on the ransomware’s key artifacts that could help organizations detect such a ransomware attack.
“If DiskCryptor is not used by the organization, add the key artifact files used by DiskCryptor to the organization’s execution blacklist. Any attempts to install or run this encryption program and its associated files should be prevented,” the FBI said.
The FBI recommended that organizations carry out regular data backups and air gap and password protect this data offline. Organizations should also make copies of critical data inaccessible for modification or deletion from the system where the data resides.
The Bureau also recommended organizations implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, secure location.
