Do you use antivirus software on your computer? These days, I don't use a separate antivirus or anti-malware program on either my Mac or my Windows PC. Whether that's actually safe is a question that keeps coming up. Some argue that modern operating systems have become secure enough, with robust built-in protections and better defenses against the latest threats, that additional security tools are no longer necessary. Others point out that malicious code and malware we don't even know about could still be hiding and running on our systems.
Smishing and ransomware attacks are still on the rise, both in frequency and scale. There are plenty of opportunities for attackers to exploit a moment of carelessness. But there's a pattern here: they get you to install something.
My general rule is to install only the apps I initially need on the computers I use for work, and nothing else. That's also one reason I tend to use my iPhone for financial transactions. Everything is packaged into a dedicated app, so I don't have to go through multiple applications. That reduces the chances of malware sneaking in disguised as some security app I don't recognize—or of me overlooking something suspicious simply because I assume it's a security program. In the end, an attack often begins when something gets installed on your device without your real intention or understanding. No matter how much you want whatever is being offered, think carefully before hitting that Install button.
Fortunately, operating systems have become quite sophisticated in their security policies, and everyday users have seen a significant reduction in viruses and common malware infections on personal computers. But there are still ways for unwanted software to get in. Sometimes an unfamiliar app is installed without the user realizing what it does. In other cases, the software doesn't just masquerade as an ordinary app. It opens the computer's Terminal and executes code directly.
In other words, pretending to be an ordinary app has become more difficult. But that also means attackers may turn to less obvious ways of getting software installed and running on your computer.
I used Terminal quite a bit recently while reviewing a MacBook Pro. Terminal is a direct way to issue commands to your computer. You type commands into a dark window, and the system executes them. The apps we normally use package together specific functions and the permissions needed to perform them. Terminal, on the other hand, may look like it does nothing at all, but it gives you access to an enormous range of the computer's capabilities. Back in the DOS days, this was pretty much how we used computers. Today, Terminal is generally reserved for specialized tasks or for working with parts of the system that require a deeper level of access.
Some readers asked how I installed and tested LLMs on my Mac. These days, there are tools that make it easy to download and run an LLM or a specific AI model. It's a bit like installing an MP3 player and loading music files into it. But you can also install models directly through Terminal. I wanted to compare their performance by running the same commands over and over, so I wrote code to automate the process.
Essentially, I built an app that writes and runs program code, installs the models I need, executes them repeatedly, and turns the results into data that I can present and compare. But look at it from another perspective: someone else could use the same approach to get into your computer and do things behind the scenes without your knowledge.
You've probably seen apps that automatically open Terminal after installation, type in a long string of predefined commands, and then close the window almost immediately. They may do this to obtain additional permissions or install components that run in the background.
The problem is that unless you're a developer who can read and understand the code, you have no idea what just happened. If something like this looks suspicious, one option is to copy the entire command and ask an AI assistant such as GPT or Gemini to explain what it does.
With macOS 26.4, Apple has introduced warnings that appear when commands entered into Terminal could affect the system. It's essentially asking, "Are you sure you want to do this? Do you understand what this command does before you run it?"
The truth is that most ordinary Mac users—and Windows users, for that matter—have very little reason to use Terminal. One of the more common reasons people end up using it is to install pirated software or bypass licensing restrictions. Of course, there are legitimate applications that require Terminal commands, but you should be particularly cautious when dealing with pirated software or apps from sources you can't clearly identify.
These warnings could be inconvenient for some people. Developers, in particular, use Terminal all the time. Imagine having to dismiss a warning saying, "Hey, this code could be dangerous," every time you enter a command. That would quickly become frustrating.
Apple says the system uses machine learning to assess how Terminal is being used. It considers patterns such as how frequently you use Terminal, what kinds of commands you run, and how you work with developer tools. If the system recognizes that you're using Terminal appropriately for its intended purpose, it won't necessarily show you a warning every time.
That doesn't mean potentially dangerous commands are ignored. The system still warns users about malicious code that could attack the system. Threat detection patterns are continuously updated and checked locally using on-device AI, so the contents of your Terminal commands aren't sent outside the device for this analysis.
macOS 26.4 also takes a more proactive approach to security updates. Safari, for example, is an important potential entry point for threats. Rather than making a big announcement every time it needs an update, Apple can deliver certain updates automatically in the background. You could compare this approach with the way Chrome handles updates.
Let's take a closer look at security in modern macOS. Software security is important, but hardware attacks are also a growing concern. Attackers may exploit vulnerabilities in components such as CPUs and memory, or even physically remove or modify chips. Apple puts considerable emphasis on these areas and the measures designed to protect against such attacks.
Of course, these sophisticated attacks are more commonly directed at enterprises and professional targets than at ordinary personal computer users.
But Macs are used by everyone from students and office workers to professional users. Because Apple makes both the hardware and the operating system, it can manage security across the entire stack, from hardware to the OS to software. Memory integrity is one example.
With the M5 and A19 processor families, Apple has strengthened memory integrity protections. Memory attacks can exploit mistakes in memory management, which are relatively common in programming languages such as C and C++ that provide extensive access to system resources.
Programs need to allocate memory when they need it and release that memory when they're finished. But things can go wrong. A process might retain memory it should have released, for example, creating opportunities for attackers to exploit that memory and repeatedly execute malicious operations.
To get a little more technical, one related category of attack involves pointer manipulation. If you've ever studied C, you'll know that pointers can be one of the most frustrating parts of the language. After an application has finished using a memory location, the associated pointer or reference needs to be handled correctly. If the program doesn't manage that process properly, an attacker may be able to take advantage of the resulting vulnerability and insert malicious code into a place the system still considers legitimate.
The result is that malware can run without the system immediately recognizing that anything is wrong. This isn't a problem unique to Macs. It's a long-standing class of attack affecting Windows, Linux, and other operating systems as well.
Operating systems have therefore developed increasingly sophisticated software-based defenses to monitor what processes are doing with memory and detect suspicious behavior. But imagine an attacker who leaves a legitimate process's name and memory space intact and simply replaces the contents with malicious code. That becomes much harder to detect. The attacker can even make sure the modified code occupies roughly the same amount of space.
The memory integrity architecture introduced with the M5 and A19 takes another approach: it adds a hardware-based verification step.
The basic idea is to divide memory into smaller units and attach tags that cannot simply be read from outside. When a program is allocated memory, it receives the corresponding tag. The system then checks the tag when the program accesses that memory.
Think of it like entering a hotel. Getting into the building doesn't mean you can enter every room. You still need the right key for the particular room you want to access.
You might wonder why this isn't simply the obvious way to handle security. But, as with any security mechanism, the process of issuing keys, checking them, and eventually returning or invalidating them all takes work. That work can affect performance.
Memory access speed has a direct impact on application performance. If the system had to stop and check a key every time someone entered a room, bottlenecks would quickly develop. The same principle applies to memory: performing these checks entirely through software could introduce substantial overhead. By implementing the mechanism in hardware, Apple can reduce the performance impact.
Another interesting example is Apple's laser lab. This involves examining changes in temperature and voltage across different parts of the hardware, rather than looking only in software behavior.
Imagine a Mac being subjected to a series of targeted attacks. Someone attempts to exploit its memory, attack the CPU, and force the system to perform operations it was never supposed to perform. The result might be the theft of information or the encryption and compression of files as part of a ransomware attack.
Those unexpected operations require the processor to do additional work. They can change power consumption and generate additional heat.
Researchers can use precision instruments to measure these physical changes. A processor performing a particular workload normally produces a relatively predictable pattern of power consumption and heat. If that pattern changes unexpectedly, it may provide a clue that something unusual is happening.
Likewise, if researchers understand which parts of a Mac or its chips tend to heat up under particular attack conditions, they can use those physical signals as additional evidence that the system is under attack.
Of course, you might be wondering whether we really need to understand all these complicated mechanisms. I don't think we do. It's the platform's job, the operating system's job, and the device manufacturer's job to make these systems secure on our behalf.
When people say that Macs are more secure, part of what they mean is that Apple brings these different layers together. Hardware, the operating system, and even the policies governing apps distributed through the App Store can be considered as parts of one security framework. That integrated approach can reduce certain risks.
Does that mean Windows or Android aren't secure? Not at all. Both operating systems have substantial security protections. The challenge is that implementing hardware-level security consistently across a broad range of chips and devices is more difficult. Outside the enterprise market, it isn't always practical to include dedicated security hardware in every product.
That's one reason security can differ between consumer and enterprise devices, as well as between manufacturers. There is no single approach that works equally well for every device.
Windows 11, for example, has hardware security requirements that can prevent installation on computers whose processors or security capabilities don't meet the requirements. But policies like these can also create considerable confusion in a general-purpose operating system. Why can't my computer run Windows 11? Is there a way around the restriction? These are questions that inevitably come up.
App marketplaces are another area of ongoing debate. Personally, I think open app marketplaces have more disadvantages than advantages when it comes to security.
Many modern security problems begin when something is installed on a device, and vulnerabilities often arise when users bypass the normal installation process. If you restrict app downloads to a clearly defined store and prevent apps from being installed from other sources, you can concentrate your security efforts on managing that store. You could allow well-managed third-party stores, of course, but for ordinary users, a more centralized approach is both simpler and safer.
Ultimately, security is about the entire system, and attackers look for even the smallest gap in that environment. Increasingly, that gap is the human element.
That's why active security warnings and mechanisms such as sandboxing are so important. Apple can approach these vulnerabilities from a single perspective because it manages security across hardware, the OS, and software. Windows and Android offer more flexibility, but that freedom comes with a little more responsibility for the user.
If you use these operating systems safely and follow their security guidelines, it's fair to say that you can use them without running into security problems. When a warning asks whether you really want to install an unverified app, simply taking a moment to be cautious can eliminate a substantial portion of the risk.
So, stay safe out there, and remember to give your computer's security a little thought every now and then.
