Microsoft Defender is a popular and robust antivirus solution that comes bundled with Windows operating system to keep the user's computer and data protected from malware and other potential threats. However, cybercriminals are always looking for new ways to exploit even the most reliable security systems. In this article, we will discuss the details of the newly discovered vulnerability with a Common Vulnerabilities and Exposures (CVE) ID of CVE-2023-24860, affecting Microsoft Defender. This vulnerability has the potential to lead to a Denial of Service (DoS) attack.

Microsoft has officially acknowledged the vulnerability and provided patches to mitigate the risk. Before diving into the technical details of the Microsoft Defender DoS vulnerability (CVE-2023-24860), let's refresh our understanding of Denial of Service attacks and their implications.

Denial of Service Attacks

A Denial of Service attack aims to make a computer, network, or service unavailable to its intended users by overwhelming it with a flood of useless traffic, consuming the resources, or causing the system to crash. Successful DoS attacks can lead to prolonged downtime, loss of data, and significant financial and reputational damage.

CVE-2023-24860 Vulnerability Details

The Microsoft Defender vulnerability, identified as CVE-2023-24860, allows an attacker to exploit the antivirus program's scanning feature by creating a specific file that, when scanned, will consume disproportionate system resources. This excessive resource consumption can lead to a DoS condition.

The vulnerability relies on the attacker's ability to create a file that triggers the malicious behavior when scanned by Microsoft Defender. For this to happen, the attacker must entice the victim to download and execute the malicious file or gain unauthorized access to the victim's machine by exploiting other vulnerabilities (such as those found in outdated software).

To better understand how the vulnerability works, let's look at a code snippet illustrating the potential exploitation scenario:

# Create a malicious file with a large, nested structure
malicious_file = create_nested_structure(max_depth=100000)

# Save the file to disk
with open("malicious_file.txt", "w") as file:

# Microsoft Defender starts scanning the file and gets caught in an infinite loop or crash

In the above example, the create_nested_structure function generates a large, deeply nested structure that, upon scanning by Microsoft Defender, can bog down the system and result in a DoS condition.

Refer to the original reference for this vulnerability here.

Mitigation and Patches

Microsoft has been made aware of this vulnerability and has released patches to remediate the issue. To protect yourself from this vulnerability, it is essential to keep your Microsoft Defender—along with all other software—up to date with the latest patches.

You can find the security update relevant to your system and detailed instructions on how to install it on Microsoft's Security Update Guide page.


CVE-2023-24860 is a noteworthy vulnerability in Microsoft Defender that could lead to a Denial of Service attack on a victim's machine. Awareness of the vulnerability, keeping your software updated, and adhering to safe online practices can help mitigate the risk posed by this and other exploits. As malicious actors constantly search for new vectors of attack, staying informed and vigilant is key to protecting your digital assets.


Published on: 04/11/2023 21:15:00 UTC
Last modified on: 04/19/2023 13:47:00 UTC