Banking Trojans Disguised As ICS/SCADA Software Infecting Plants

A renowned ICS/SCADA security researcher has discovered a surprising twist in cyberattacks hitting plant floor networks: traditional banking Trojan malware posing as legitimate ICS software updates and files rather than the dreaded nation-state custom malware in the wake of Stuxnet.

Kyle Wilhoit, senior threat researcher with Trend Micro, recently found 13 different types of crimeware versions disguised as human machine interface (HMI) products Siemens Simatic WinCC, GE Cimplicity, and Advantech device drivers and other files. The attacks appear to be coming from traditional cybercriminals rather than nation-state attackers, and are not using cyber espionage-type malware.

"It's an interesting trend -- traditional banking Trojans, not targeted attacks," Wilhoit says.

The ICS/SCADA community has been understandably on alert for the next Stuxnet-type attack, and recent discoveries of malware such as Havex and BlackEnergy, both of which have been detected targeting that environment, have put these types of nation-state, targeted attacks in focus.

But Wilhoit says his findings show that traditional cybercriminals are looking for targets in the ICS/SCADA world, and likely for money-making rather than spying or sabotage purposes. "So to succeed in attacking SCADA, you don't have to necessarily be targeted in nature... The ultimate end goal here is probably not industrialized espionage, but to get banking credentials" or other financially lucrative information, he says.

Bottom line: Many ICS/SCADA systems are soft targets. "We are starting to see a migration of attackers starting to realize SCADA is a good attack vector... because it's so insecure," he says. Many HMI machines are Windows-based and either don't run anti-malware software, or aren't updated with the latest signatures. "A lot we are finding are caught no problem with [up-to-date] antivirus," he says.

Wilhoit says targeted attacks on critical infrastructure via Havex and BlackEnergy indeed remain a threat, but the crimeware-based attacks he's seeing ultimately could be catastrophic as well. "It's just as scary. If an operator's HMI is infected... The damage can be the same even if it's not an advanced attack," he says.

HMI systems are highly sensitive to disruption, he says, so a malware infection via a financial Trojan could bring down the system as well. "HMI systems are very finicky, so it doesn't take much to make these things fall over. Financial information could be stolen, but what if an [HMI] box drops inadvertently?" he says.

Wilhoit says he first noticed a spike in these attacks in October, and he's not sure what prompted the jump in activity. The attacks originate as spear-phishing campaigns and drive-by downloads: When the victim visits the malicious link, the fake HMI product uploader -- which is the Trojan -- infects his machine. In some cases, the victim is redirected to a website that appears to be that of Siemens to dupe the user into downloading a WinCC update, for example.

Wilhoit says he recently found 32 malware samples posing as WinCC software. "They have been using the WinCC naming convention and file structure, as malware," he says.

"The shift… is they [attackers] are utilizing valid applications, valid SCADA naming conventions, so the banking Trojan looks like SCADA software," he says. "They're not exploiting vulnerabilities in those products," but using their naming conventions and file names as cover, he says. He says he has alerted the HMI vendors whose products are being used as lures in the attacks.

[ICS/SCADA experts say open-source network security monitoring software is a simple and cheap way to catch hackers targeting plant operations. Read Using Free Tools To Detect Attacks On ICS/SCADA Networks.]

At the S4 ICS/SCADA conference in Miami next week, Wilhoit plans to update his latest findings on the attacks, as well as demonstrate live the lifecycle of these SCADA malware attacks, from how they grab system information, scan systems, grab passwords, and exfiltrate data.

"I'm going to create malware targeting an ICS system and hiding its traffic on a valid ICS Modbus" network, he says. "I'm doing it to show how fast you can craft malware that's not terribly advanced but will bypass AV or" other security measures, he says.

Application whitelisting, keeping AV updated, and network security monitoring, are ways to defend against these attacks, he says. "Everyone is concerned about a targeted attack... me, too," he says. "But these run-of-the-mill types of malware can cause damage. They are almost a bigger threat than a targeted attack."

Meanwhile, Wilhoit says he's still trying to discern more details about the banking Trojan ICS SCADA attackers, as well as which industries are getting hit most. He says the attacks are a weakeup call that it doesn't take a nation-state to disrupt a power plant or other plant-floor operation. "It's not hard to do and you don't have to be a virus-writer to do this," he says.