The name of the company hit by the second attack was withheld by FireEye which issued a blog post on Wednesday, providing detail about the Triton attack framework and its techniques, tactics and procedures.
Triton has been named as such because it attacks a safety system known as Triconex which is made by Germany's Schneider Electric and used globally.
In December 2017, FireEye said it had found the new industrial control system attack framework, but did not specify where the attack took place.
Triton is built to interact with Triconex Safety Instrumented System controllers and prevents emergency shutdown of such systems.
FireEye said Triton leveraged a number of custom and commodity intrusion tools to gain and maintain access to the target's IT and operational technology networks.
It said the attack played out over a long period. "These attacks are also often carried out by nation states that may be interested in preparing for contingency operations rather than conducting an immediate attack," FireEye researchers Steve Miller, Nathan Brubaker, Daniel Kapellmann Zafra and Dan Caban wrote.
"During this time, the attacker must ensure continued access to the target environment or risk losing years of effort and potentially expensive custom ICS malware."
The malware was present on the system for almost a year before it gained access to the safety instrumented system engineering workstation, with the emphasis on operational security. There was no collection of data as seen in espionage attacks.
Some of the techniques used to hide the malware were:
- They renamed their files to make them look like legitimate files, for example, KB77846376.exe, named after Microsoft update files.
- They routinely used standard tools that would mimic legitimate administrator activities. This included heavy use of RDP and PsExec/WinRM.
- When planting webshells on the Outlook Exchange servers, they modified already existing legitimate flogon.js and logoff.aspx files.
- They relied on encrypted SSH-based tunnels to transfer tools and for remote command/program execution.
- They used multiple staging folders and opted to use directories that were used infrequently by legitimate users or processes.
- They routinely deleted dropped attack tools, execution logs, files staged for exfiltration, and other files after they were finished with them.
- They renamed their tools' filenames in the staging folder so that it would not be possible to identify the malware's purpose, even after it was deleted from the disk through the residual artifacts (e.g., ShimCache entries or WMI Recently Used Apps).
- They used timestomping to modify the $STANDARD_INFORMATION attribute of the attack tools.
Additionally, the researcher said, the following methods were used:
- The actor gained a foothold on the distributed control system (DCS) but did not leverage that access to learn about plant operations, exfiltrate sensitive information, tamper with the DCS controllers, or manipulate the process.
- They then gained access to an SIS engineering workstation. From this point forward, they focused most of their effort on delivering and refining a backdoor payload using the Triton attack framework.
- They attempted to reduce the chance of being observed during higher-risk activities by interacting with target controllers during off-hour times. This would ensure fewer workers were on site to react to potential alarms caused by controller manipulation.
- They renamed their files to make them look like legitimate files, for example, trilog.exe, named after a legitimate Schneider Electric application.
FireEye said the group had been operational since at least 2014. Though the company is known be one that is quick to attribute attacks, it remained silent about Triton's origins this time. Last year, FireEye had claimed that Triton was connected to a Russian Government-owned research institute.
After the first Triton attack, the security group Area 1 Security speculated that Triton could have been written jointly by Russia and Iran; an artifact in the software had a Russian name. But while the report said Russian involvement was possible, it also pointed out that such an artifact could be a false flag.