Can Zeus Trojans Infect macOS?

Yes, the Zeus virus, also known as Zbot, primarily targets Windows systems. However, variants and similar types of malware can potentially affect other operating systems, including macOS. While traditional Zeus variants are designed for Windows, cybercriminals often create cross-platform versions or use similar techniques to exploit vulnerabilities in different operating systems. Macs are generally considered more secure than Windows machines, but they are not immune to malware. Therefore, it is essential to maintain good security practices such as keeping your operating system and software up to date, using strong passwords, and employing reputable security software to help protect against various types of malware, including those inspired by Zeus.

Technically: Is Zeus a Virus?

Zeus is not actually a virus because it doesn’t self-replicate. All viruses self-replicate. Instead, it looks like it’s a Trojan application which means the user must be tricked into installing the application on their computer. Zeus is a Windows application that will not run natively in macOS. The only way Zeus might be able to run on a Mac is if the user installs the Windows operating system either with Boot Camp or in a virtual machine like VMware Fusion, Parallels Desktop, or VirtualBox and then installs a Zeus Trojan application in Windows. However, even in this scenario, the malware would not have access to anything in macOS.

Note that there are zero macOS X viruses in the wild, as it has been since the first version of macOS X was released way back in 2001. The only piece of macOS malware that came close was a LAN worm called OSX/Leap-A back in 2006. This worm required the user to:

Receive an uninvited file transfer through the iChat message client. Download the file attachment to their computer. Manually decompress the downloaded file and run it. Provide administrator credentials when asked by the system before running.

Only after performing all these actions would the worm actually run to infect the system. Once infected, the worm would attempt to replicate by sending download requests to the user's chat contacts but only those contacts that were available on the local area network. In other words, it did not attempt to spread over the internet. For replication to actually succeed, other users would need to perform the above steps, otherwise, replication would fail. Consequently, OSX/Leap-A did not spread far, and Apple long ago updated security features in macOS to protect against such attacks, which are unheard of in the Mac community today.

Are There Trojans for macOS?

While the Zeus trojan specifically targets Windows, there are indeed plenty of Trojans out there that do run on macOS. Most macOS Trojans are distributed with torrents of pirated Mac software, typically from Adobe and other major vendors of high-priced software. Some macOS apps are bundled with adware, so when the user installs these questionable applications, adware is also installed. Usually, unsuspecting users download them from pornographic or other untrustworthy websites that try to convince visitors to download a video codec or application. Adware typically attempts to hijack web browser settings, allowing attackers to display ads to users, modify the content of web pages viewed by users, and spy on their web browsing behavior.

How to Protect Yourself

To protect yourself from such Mac malware, you should strictly download software from trusted sources. For example, instead of downloading an application from CNET Downloads or another third-party site, you would go to the Apple App Store or download it directly from the app developer's website. For most non-App-Store Mac applications, you can also verify MD5/SHA hashes of the app published by the developer to match what you actually downloaded. Mac users who suspect they have malware running on their computers should use tools like Malwarebytes and KnockKnock to protect from and eradicate such unwanted apps from their systems.