How good is Windows Defender in 2025?

Summary

In this video, the performance of Windows Defender in 2025 is put to the test with over 2,000 new malware samples. The test reveals a detection rate of 92%, but also highlights critical weaknesses, such as system crashes and malware replication. While Defender detects threats based on cloud signatures, it struggles with behavioral protection and can be overwhelmed by multiple attacks. The video contrasts this with the zero trust and default deny approach used by third-party solutions like Threat Locker, which offers additional security measures to prevent unauthorized executions. Overall, Windows Defender is improving but still has room for enhancement in its real-time defense capabilities.

Takeaways

• 😀 Windows Defender in 2025 has strong detection capabilities, starting with 100% detection rate but dropping to 92% as the test progresses.
• 🖥️ The test used over 2,000 new malware samples from various sources to evaluate Windows Defender's effectiveness.
• 🚨 The malware begins to cause significant system issues, including display problems and freezing, with one sample ('Unicorn') disrupting the screen.
• 💻 Despite detection of some malware, the system experiences severe performance problems, including a black screen and system instability.
• 🔄 A hard reset helps recover the system, but the malware continues to cause issues in the background, indicating missed detections.
• ⚠️ Some malware, even after being detected by Windows Defender, successfully executed and caused damage, highlighting potential gaps in real-time protection.
• 📊 Microsoft Defender's cloud-based detection relies on the system’s telemetry, which results in delayed responses and vulnerabilities during the first execution of malware.
• 🛠️ Behavioral protection needs to be manually enabled in Group Policy settings to provide more effective defense against evolving threats.
• 🔍 The test showed that Microsoft's signature-based detection is competitive, but there are concerns with behavioral protection and cloud delays.
• 🛡️ Windows Defender is comparable to other antivirus solutions, offering solid protection, though it’s not foolproof against new, sophisticated malware.
• 🔒 The zero trust approach promoted by the test sponsor, Threat Locker, offers an additional layer of security, particularly for enterprise environments to block unauthorized software execution.

Q & A

What was the main objective of the test conducted in the video?

The main objective of the test was to evaluate how effective Windows Defender is at detecting and protecting against over 2,000 pieces of new, unclassified malware, including potential threats that users may encounter in real-world scenarios.

How did the detection rate of Windows Defender perform during the test?

Windows Defender's detection rate started at 100% but dropped to 92% as the test progressed, indicating that while it initially detected many threats, it struggled with some newer or more sophisticated malware.

What role did the 'Unicorn' malware play in the test?

The 'Unicorn' malware significantly impacted the system, causing it to freeze, create multiple copies of itself, and ultimately make the system inoperable. It demonstrated weaknesses in Defender's ability to prevent certain malware from executing.

What was the effect of the malware on the test system's stability?

The malware caused serious instability, including black screens, system freezes, and the creation of many malicious files. At one point, the system was rendered inoperable, requiring a hard reset to recover.

Why was the malware detection rate reduced as the test continued?

The reduction in the detection rate occurred as more malware executed on the system, with new threats bypassing Defender's protection. The system also struggled to cope with the increasing number of malware processes running simultaneously.

Did Windows Defender successfully block all malicious files during the test?

No, Windows Defender did not block all malicious files. Despite detecting some threats, certain malware was able to execute and cause damage, such as the 'Unicorn' malware that created multiple copies and made the system unstable.

What is the significance of the cloud-based detection system used by Windows Defender?

The cloud-based detection system allows Windows Defender to quickly update signatures and respond to new threats. However, it also leads to delays in detection, as the system relies on information from other users' experiences before it can effectively block a new threat.

How does the zero-trust approach differ from Windows Defender's approach to malware detection?

The zero-trust approach, as demonstrated by Threat Locker, operates on a default-deny principle, preventing unknown or untrusted software from executing unless explicitly allowed. In contrast, Windows Defender relies on detecting known threats and cloud signatures, which may allow some malware to execute before detection.

What weaknesses in Windows Defender were highlighted during the test?

Some of the weaknesses highlighted include Defender's reliance on cloud-based detection, which can result in delayed responses to new threats, and its lack of strong behavioral protection unless manually enabled in group policy settings.

What does the result of this test suggest about the reliability of Windows Defender for enterprise environments?

The test suggests that while Windows Defender offers decent protection against many threats, its reliance on cloud-based signatures and delayed detection may not be sufficient for enterprise environments where more immediate and robust protection is needed. Third-party solutions like Threat Locker, using zero-trust security, may provide more effective defense.