Why Clicking a Link Isn’t Always Safe
Recently, I had an interesting conversation with a developer about one of the most common pieces of advice we hear today – “Don’t click random links.” The developer argued that there wouldn’t be much harm if he didn’t interact further after clicking a link, especially on his phone. He also pointed out that browsers like Chrome use a sandbox to prevent any damage from being done, essentially isolating any malicious activity to keep the rest of the system safe.
He had another argument, too. If a serious issue like a zero-day vulnerability was potential, he would simply wait a day after a patch release to avoid the problem.
While both points have some merit, they oversimplify the risks associated with zero-day vulnerabilities, which are far more dangerous and elusive than many realise. Let’s break this down and explore why more than relying on sandboxes and waiting for patches may be needed.
What is a Zero-Day Vulnerability?
A zero-day vulnerability is a security flaw in software that is unknown to the software’s developers and security teams. Because it hasn’t been identified or patched, cybercriminals can exploit it before any defence or fix is available. This is where the term “zero-day” comes from—zero days of warning or preparation.
When an attacker finds and uses such a vulnerability, it’s a zero-day exploit. These are particularly dangerous because:
- No Patch Exists: Since the vulnerability is unknown, no fix has been made available yet.
- Targets Everyone Using the Software: Until a patch is released, anyone using the vulnerable software is at risk.
- Exploitation is Often Silent: Attackers can exploit these vulnerabilities without the user knowing, even with minimal interaction, such as clicking a link.
Sandboxing Isn’t Foolproof
While Chrome’s sandboxing is an effective security measure, it’s not an invincible solution. A sandbox limits the damage an application can cause by isolating processes. Still, sophisticated zero-day exploits have been known to bypass sandboxes. Attackers often target low-level vulnerabilities in browsers or the operating system to break out of the sandbox.
Even though sandboxing reduces the risk, it doesn’t eliminate it. Some zero-day attacks are designed to exploit vulnerabilities in the sandboxing process.
Zero-Days on Mobile: Phones Aren’t Immune
Many people think their smartphones are safer because of app sandboxing and a more closed ecosystem than traditional desktop systems. But smartphones aren’t immune to zero-day exploits either. Phones are often prime targets due to the sensitive personal data they store (like photos, messages, and location information).
Mobile operating systems like Android and iOS regularly release updates. Still, once again, there is a window of vulnerability between when attackers discover a zero-day and when a patch is issued. Moreover, clicking on a malicious link on your phone might activate an exploit with no visible signs until it’s too late.
The Problem with “Just Waiting a Day”
One key point my developer friend made was that he would just wait a day after a patch release if a zero-day vulnerability became public. This approach sounds safe at first glance, but in reality, it’s not that simple. Here’s why:
- Zero-days don’t come with warnings: When attackers discover zero-day vulnerabilities, they often remain secret until the exploit is used widely or publicly disclosed. There’s no guaranteed notice that a zero-day is in play, so waiting a day may not protect you.
- Patches take time: Even after a patch is developed, it might take days (or longer) for it to roll out to all users. Attackers can take advantage of this delay.
- Immediate exploitation: As soon as a vulnerability becomes public knowledge, attackers may quickly exploit unpatched systems.
- Essentially, you can’t always predict when a zero-day will hit or how fast the patch will arrive. Assuming you can “wait it out” is like hoping the storm won’t reach you.
So, Should You Click That Link?
The best approach is to be cautious, even if you’re confident in your device’s security measures. Zero-day vulnerabilities represent unknown risks, so you’re better off not clicking on links from untrusted sources—especially if you believe nothing bad can happen by just clicking.
Cybersecurity isn’t about whether you personally encounter zero-days. It’s about reducing your exposure to threats. Every click counts when dealing with the unknown, and the risks can be severe.
Final Thoughts
Zero-day vulnerabilities remind us that no system is perfectly secure, and even advanced protections like sandboxing can sometimes be bypassed. While waiting for patches may offer some protection, it’s not a fail-safe strategy for rapidly spreading zero-day exploits.
The takeaway? Be skeptical of unfamiliar links and stay vigilant—especially when a zero-day lurks. After all, the best defence is not putting yourself in harm’s way in the first place.
