IoT Malware Campaign Infects Global Manufacturing Sites

The infection uses Lemon_Duck PowerShell malware variant to exploit vulnerabilities in embedded devices at manufacturing sites.

A new malware campaign built to exploit flaws in connected devices is targeting manufacturers around the world and affecting products from smart printers to heavy operational equipment.

Researchers at TrapX Labs first saw this attack targeting Latin American manufacturers in October 2019. Since then, it has continued to expand, with a peak in December and ongoing growth this year in regions including North America, Africa, and the Middle East, says TrapX CEO Ori Bach.

“Given the nature of the attack, it makes sense to make it global,” Bach explains. “The attacker wants to cover as much real estate as possible.”

This attack campaign uses a self-spreading downloader that runs malicious scripts as part of the Lemon_Duck PowerShell malware family. The threat exploits vulnerabilities in Windows 7 embedded devices and specifically targets manufacturing sites, where infected devices can possibly malfunction and pose risks to employee safety, supply chain disruption, and data loss.

Attackers employ several methodologies to break into manufacturing sites, Bach says, but ultimately their initial entry occurs through two main attack vectors. The first is a classic phishing email; if successful, an intruder can use a variety of tools — vulnerability protocols, weak passwords, pass-the-hash, and others — to spread throughout the target organization.

The second is a supply chain infection. An attacker may compromise a company where devices are manufactured so they arrive at their final destination preinfected. Once they’re connected to a target network, these malicious devices can spread malware to others on the network. These supply chain attacks make up 80% of infections in this particular campaign, Bach notes. There are many products to protect against phishing emails, he adds, but fewer exist to combat supply chain threats.

In these attacks, and many Internet of Things-focused campaigns, adversaries are not concerned with the type of device they infect. “Attackers are obviously agnostic of the operational function of the device,” he says of choosing targets. “What they care about is what this device is running.” For many devices, this is Windows 7, an operating system that stopped receiving security support earlier this year.

An example of one such device is the DesignJet SD Pro Scanner/printer, which was infected in this campaign and served as an entry point into one target network, researchers report. It is used to print technical engineering drawings and holds sensitive data for the manufacturer’s products; it also ran Windows 7 embedded and had access to the Internet and various projects.

In a separate supply chain attack, attackers infected an automatic guided vehicle (AGV), a piece of equipment used to transport materials or perform tasks in industrial environments. AGVs run on batteries or electric motors and could threaten employee safety in a work zone. This incident caused confusion on the production line, possibly damaging products that AGVs assemble. The target network contained three other AGVs, all of which were preinfected with malware.

Manufacturing Malware 
Lemon_Duck was developed as a cryptominer, says Bach. In this scenario, the malware has been customized to perform capabilities beyond mining for cryptocurrency on a target machine.

This particular variant scans a network for potential targets, including devices with SMB (445) or MSSQL (1433) services open. When it finds one, the malware runs multiple threads with several functionalities. It first attempts to brute force the services with usernames and passwords to gain access so it can further download and spread the malware via SMB or MSSQL. Another one of its functionalities is to run invoke-mimkatz via import-module to obtain NTLM hashes and gain access, another means of downloading and spreading the malware via SMB. Once SMB access is gained, it uses a tool to copy itself to the target device and run as a target.

Some of these functions may not work, which is why Lemon_Duck comes with backup plans. If it fails via brute force or NTLM hashes, it will attempt to use the EternalBlue SMB vulnerability to gain system access and run as a service on the target. Lemon_Duck persists via scheduled tasks, which run PowerShell scripts to further download Lemon_Duck PowerShell scripts.

This attack presents a challenge to manufacturers because devices are often not fully patched and can be difficult to wipe clean, says Bach. What’s more, they can be reinfected by other machines on the network after the malware is removed because the nature of Lemon_Duck is to spread quickly. Patching is more difficult in an operational technology network than a traditional IT environment.

The end-of-support for Windows 7 compounds the challenge for manufacturers because equipment is difficult to update and expensive to replace. Bach advises organizations to start by mapping out the products they have in their environment and working with each individual vendor to determine what needs to be replaced and what needs to be upgraded to a new OS.

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Kelly Sheridan is the Staff Editor at Dark Reading, where she focuses on cybersecurity news and analysis. She is a business technology journalist who previously reported for InformationWeek, where she covered Microsoft, and Insurance & Technology, where she covered financial … View Full Bio

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