Protect Your Email: Understanding Malicious URL Defense Strategies

If you're using cloud email, knowing how to check if a link is safe isn’t optional anymore. Research shows that one in ten employees will click on a malicious link. One click is all it takes: account compromise, data theft, financial loss, reputational damage, downtime, pick your poison.

That’s why advanced link protection isn’t just a “nice to have”- it’s critical. A URL protection email link is the core of that defense, actively shielding users from dangerous redirects. But what exactly does this technology do, and how does it work behind the scenes?

Don’t worry, we’ll break it down. In just a few minutes, this article will walk you through how malicious link protection actually works, and why it’s now a non-negotiable part of any serious email security strategy.

Understanding URL Protect and Its Role in Email Security

Despite the fact that HTML email allows users to hover over a link to view its destination, the reality is that the majority of us do not engage in this security best practice. Malicious URL protection eliminates the risk of a potentially devastating “wrong click” that could result in the submission of credentials or the loss of control of one’s device through the download of ransomware, spyware, or other malicious executable software.

A strong site security foundation also includes using real-time URL protection to prevent credential theft and data breaches.

While many email security solutions rely on URL rewriting to detect malicious links, this strategy can provide users with a false sense of security, often doing more harm than good. While IT professionals may understand how URL rewriting works, most users see a link labeled ‘safe’ and assume it is, making it harder to check link safety by looking at the URL alone.

Thus, URL rewriting can have the side effect of increasing the likelihood that users will click on malicious links.

Guardian Digital’s malicious URL checker goes beyond traditional email filtering by actively scanning URLs and embedded attachments for threats. Guardian Digital URL Protect service takes a different approach to combating malicious URLs, providing multi-layered detection and blocking of malicious URLs by comparing domains and hosts against common blocklists and scanning destination websites in real-time to determine if they are malicious or safe. 

With this feature, URLs are also evaluated by a malicious link scanner for credential content to detect fraudulent, zero-day credential phishing sites. If a link is unsafe, the email in which it appears never reaches the recipient.

Their URL Protection also acts as a link checker, conducting a dynamic analysis of all files to extract links from Microsoft Office documents, PDFs, archive files (ZIP, AIZip, JAR), and other file types (uuencoded, HTML). It uses advanced techniques involving machine learning for real-time analysis.

The image above is a phishing email that was identified and quarantined by Guardian Digital EnGarde Cloud Email Security. The email contains a malicious link that leads to a fraudulent website, where the recipient is prompted to enter their account credentials, which would then be in the hands of the attackers behind this scam. 

While this email may appear legitimate at first, there are some definite “red flags” that indicate it is fraudulent. First, the email conveys a sense of urgency in both the subject line and the body, which is intended to encourage users to act quickly without carefully examining the email or thinking things through. The nonspecific salutation and signature are also indications that this email is fraudulent.

Stats and Trends That You Should Be Aware Of 

• Small businesses face a growing threat from phishing, with one in 323 emails sent to small companies containing a targeted malicious link, often opened by users who don’t check if a link is safe. This highlights the urgent need for effective URL protection.
• Guardian Digital EnGarde Cloud Email Security has identified and blocked more phishing emails containing malicious links in recent years than ever before in the company’s history.
• A recent survey conducted by Osterman Research found that 64.3% of organizations expect the threat level of phishing attacks against their organization to rise this year. 

Why URL Defense Is More Important than Ever 

Cybercriminals are increasingly targeting remote workers and cloud email users with sophisticated phishing, malware, and business email compromise (BEC) campaigns. The majority of these scams use malicious URLs, which lead to fake login pages on fraudulent websites.

A slew of recent phishing campaigns are targeting consumer trust in video conferencing platforms, including Zoom, Microsoft Teams, and Google Meet, to steal personal information and wreak further havoc in people’s lives. One such campaign involves a fraudulent Microsoft Teams email containing a button to “open” Teams, which is a malware link that will download malware to the user’s computer.

These links are flagged as malicious by the Guardian Digital URL Protect service, which eliminates the need for users to know how to check if a link is safe in the first place.

The above image is a fraudulent Microsoft Teams email blocked by Guardian Digital EnGarde Cloud Email Security. The “Recover account” link in this email is malicious and, when clicked, would install malware on the victim’s device. This phishing email is extremely convincing, and without implementing malicious URL protection as part of a comprehensive email security solution, it would be easy to fall for this dangerous scam. Using a URL email protection link adds an automated checkpoint that prevents users from reaching harmful domains even if they click.

Still Have Questions?

Here are a few quick answers to some common questions about securing your email with URL protection:

What is URL protection, and why does it matter?
It catches what people miss. Every link is scanned in real time, flagged if it’s malicious, and blocked before it lands. Most users can’t tell if a link is safe on sight. That’s why URL protection matters — it stops credential theft and malware before there’s a chance to click.

How can I check if a link is safe before clicking?
Hover. Read the domain. If something feels wrong, it usually is. But attackers hide bad links in plain sight, so manual checks only go so far. A trusted link checker or malicious link scanner will do it better — no guessing, no second-guessing.

What’s the best way to check link safety in cloud email?
You don’t. On mobile, you rarely see the full URL, and attackers count on that. A URL email protection link expands and scans it behind the scenes, cutting the risk before the message hits your inbox.

How can you mitigate the potential risk associated with a compressed URL?
Shortened links erase context. You don’t see where they lead, which is why attackers use them. The answer: expand and scan. A malicious link scanner exposes the real destination and blocks it if it’s bad.

What should a good link protection service actually do?
Catch what users miss. That means scanning every URL in real time, blocking credential phishing, catching malware hidden in files, and protecting you even if you click. If it can’t do all of that, it’s not enough.

Next Steps for Strengthening Your Email Security

Malicious URL protection technology is most effective when implemented as part of a comprehensive, defense-in-depth security approach for email. Regularly scanning attachments and links to check link safety helps detect malware URL threats before users are exposed to them.

We strongly recommend that users select a multi-layered cloud email security solution that seamlessly integrates with their cloud platform, providing an extra layer of defense. Look for a solution that incorporates advanced, real-time malicious URL protection techniques, mitigating the risk of human error and safeguarding cloud email accounts in this time of heightened vulnerability.

Secure your organization against phishing and malicious links. Schedule a free Email Risk Assessment with Guardian Digital and discover how advanced link checker technology can defend your cloud email in 2025.