Microsoft Flags Ransomware Problems on Apple’s macOS Platform

Security researchers at Microsoft are flagging ransomware attacks on Apple’s flagship macOS operating system, warning that financially motivated cybercriminals are abusing legitimate macOS functionalities to exploit vulnerabilities, evade defenses, or coerce users to infect their devices.

In a blog post documenting its research into four known macOS ransomware families, Microsoft’s Security Threat Intelligence team published IOCs and technical details to show how ransomware actors target users on macOS-powered devices.

“While these malware families are old, they exemplify the range of capabilities and malicious behavior possible on the [Mac] platform,” Redmond said, describing its work as a “technical reference” that researchers can use and build upon to understand Mac threats and improve protections.

While the majority of ransomware attacks target Microsoft’s own Windows operation system, the company is using the research to show that the threat is cross-platform. “Attackers [are] constantly evolving their techniques and expanding their tradecraft to cast a wider net of potential targets. This is evident in the range of industries, systems, and platforms affected by ransomware attacks. Understanding how ransomware works across these systems and platforms is critical in protecting today’s hybrid device and work environments,” Microsoft said.

[ Read: Microsoft Says Mac Trojan Becoming Stealthier, More Menacing ]

The research, which has been criticized by external researchers because of the availability of prior work, confirmed that the initial infection vector of Mac ransomware typically relies on user-assisted methods like downloading and running fake or trojanized applications. 

Microsoft said it also found that the malware can also arrive as a second-stage payload dropped or downloaded by other malware or part of a supply chain attack. Once running on a device, ransomware attacks usually comprise gaining access, execution, encrypting target users’ files, and notifying the target with a ransom message.

Microsoft said its researchers looked at four macOS ransomware families — KeRanger, FileCoder, MacRansom, and EvilQuest — to build detections for its own anti-malware product and to understand how ransomware attacks evolve on non-Windows platforms.

This isn’t the first time Microsoft has used its public blog to shine a spotlight on Apple’s security hiccups. Recently, Redmond published details on a macOS Gatekeeper bypass vulnerability and called attention to a nasty macOS malware family that has evolved quickly from a basic information-gathering trojan to a stealthy backdoor with more powerful capabilities.

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Related: Microsoft Says Mac Trojan Becoming Stealthier, More Menacing

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