BlackEnergy cyberespionage group adds disk wiper and SSH backdoor to its arsenal

The group is known in the security community as Sandworm or BlackEnergy, after its primary malware tool, and has been active for several years. It has primarily targeted companies that operate industrial control systems, especially in the energy sector, but has also gone after high-level government organizations, municipal offices, federal emergency services, national standards bodies, banks, academic research institutions and property companies.

Over the past few months, the group has targeted organizations from the media and energy industries in Ukraine, according to security researchers from antivirus vendor ESET. These new operations have brought to light some changes in the group's techniques.

In November, the Computer Emergency Response Team of Ukraine (CERT-UA) reported that during the country's local elections in October, multiple media organizations were attacked with BlackEnergy malware leading to the loss of video content and other data.

According to ESET researchers, the culprit was a new BlackEnergy component dubbed KillDisk that can be configured to delete specific types of files and render affected systems unbootable.

The KillDisk variant in the attack against media organizations was configured to delete over 4,000 file types, many of which were for video and documents.

The same component was also used recently in attacks against energy companies in Ukraine, but with a different configuration. It only targeted 35 file extensions and had a timed attack option.

"As well as being able to delete system files to make the system unbootable -- functionality typical for such destructive trojans -- the KillDisk variant detected in the electricity distribution companies also appears to contain some additional functionality specifically intended to sabotage industrial systems," the ESET researchers said in a blog post.

On the eve of Dec. 23, a large area in the Ivano-Frankivsk district in Ukraine suffered a power outage. Ukrainian news service TSN reported that the outage was caused by a virus that disconnected electrical substations.

Researchers from ESET believe that this attack was performed with the BlackEnergy malware and that it wasn't the only one.

"Looking at ESET’s own telemetry, we have discovered that the reported case was not an isolated incident and that other energy companies in Ukraine were targeted by cybercriminals at the same time," they said in a report.

The KillDisk component was used in some of those attacks. In addition to wiping various file types, it had been configured to stop two particular processes, one of them possibly associated with ELTIMA Serial to Ethernet Connectors or to ASEM Ubiquity, a remote management platform for industrial control systems (ICS).

This is not the first time that BlackEnergy has been used to attack industrial control systems. In 2014, the Industrial Control Systems Cyber Emergency Response Team (ICS-CERT), a division of the U.S. Department of Homeland Security, warned that multiple companies running HMI (human-machine interface) products from General Electric, Siemens and BroadWin/Advantech had their systems infected with BlackEnergy.

HMIs are software applications that provide a graphical user interface for monitoring and interacting with industrial control systems.

Another recent addition to the group's arsenal is a backdoored version of a SSH server called Dropbear. The ESET researchers have seen the BlackEnergy attackers deploying a variant of this software on compromised machines that had been pre-configured to accept a hard-coded password and key for SSH authentication.