Medical technology giant Stryker has shared an update regarding its investigation into the recent Iran-linked cyberattack, revealing that a malicious file used by the attackers has been identified.
The Stryker incident came to light on March 11, with the hacker group Handala taking credit for the attack.
Handala, widely believed to be a hacktivist persona controlled by Iran’s Ministry of Intelligence and Security (MOIS), claimed to have wiped more than 200,000 devices, forcing Stryker to shut down offices in dozens of countries.
Some early reports indicated that Handala used wiper malware in the attack — the group has been known to use such malware — but Stryker said it found no evidence of malware or ransomware being deployed on its systems.
The most likely scenario based on the evidence available to date is that the hackers wiped systems by abusing Stryker’s Microsoft Intune instance, which is used to remotely manage desktop and mobile endpoints and applications within the organization. There is some indication that Handala leveraged credentials obtained via infostealer malware to gain access.
Stryker said the incident disrupted order processing, manufacturing, and shipping. In a statement issued on Monday, the company said it has made “meaningful progress” in restoring impacted systems.
For the first time, the company has also shared some technical information from the investigation into the incident.
“Early in our investigation, we believed there was no indication of ransomware or malware,” Stryker said. “Further into the course of our investigation, alongside Palo Alto Networks Unit 42 and other experts, we identified that the threat actor used a malicious file to run commands which allowed them to hide their activity while in our systems.”
It added, “To be clear, this file was not capable of spreading — either inside or outside of our environment. Most importantly, at no point has our investigation identified malicious activity directed towards our customers, suppliers, vendors or partners.”
Based on this brief description, the malicious file mentioned by Stryker may have been a small custom binary or script rather than actual malware. However, this shows that the hackers deployed their own tools on the compromised systems and did not rely solely on existing software to carry out their activities.
In addition to sharing updates on its investigation and restoration efforts, Stryker has made public an assessment from Palo Alto Networks to show that the incident has been contained.
The US government has officially linked Handala to Iran’s MOIS and has taken down several websites used by the threat actor.
In addition, the FBI has issued an alert sharing information about attacks allegedly carried out by MOIS threat actors such as Handala, including the malware they use.
“FBI obtained malware samples through investigations. The samples were categorized as masquerading malware (stage 1), persistent implant (stage 2), and related stage 2 malware that contained additional or unique functions. Stage 1 usually masqueraded as commonly used applications like Pictory, KeePass, and Telegram and contained the binaries for the next stage of malware.
The persistent implant malware spawned following the masquerading malware’s execution and possible user interaction with the malicious application. At this stage, the Iran MOIS cyber actors configured a command and control (C2) using a Telegram bot, allowing bidirectional communication between the compromised device and api.telegram[.]org. FBI considered the masquerading malware and persistent implant to be core functionality for the malware campaign.”
Stryker has confirmed that it is working with US government agencies in its investigation of the incident, but the malware described in the FBI alert is unlikely to be related to the attack on the medtech company if indeed no malware was involved.
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