Windows MagicDot Path Flaw Lets Attackers Gain Rootkit-Like Abilities

A new vulnerability has been unearthed, allowing attackers to gain rootkit-like abilities on Windows systems without requiring administrative privileges.

Dubbed “MagicDot,” this vulnerability exploits the DOS-to-NT path conversion process within the Windows operating system.

Here, we delve into the technical details of the vulnerability, the attack methods, the rootkit-like abilities it confers, and the mitigation strategies to protect against such exploits.

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Vulnerability Description

The MagicDot vulnerability is rooted in the way Windows handles file paths. Specifically, it is a known issue within the DOS-to-NT path conversion process that attackers can manipulate.

The vulnerability allows for the concealment of files, directories, and processes, effectively granting the attacker the ability to operate undetected on the system.

DOS Path	NT Path (MagicDot)
C:\example\example.	\??\C:\example\example
C:\example\example…	\??\C:\example\example
C:\example\example<space>	\??\C:\example\example
C:\example\example<space><space>	\??\C:\example\example
C:\example.\example	\??\C:\example\example
C:\example<space>\example	\??\C:\example<space>\example

The issue arises from the handling of file paths that include dots and spaces in a manner that is not anticipated by the system or the software operating on it.

This can lead to a variety of unexpected behaviors, including the misrepresentation of files and processes to the user and the system’s own management tools.

Attackers can exploit the MagicDot vulnerability through several methods:

1. Hiding Malicious Files and Processes: By using specially crafted file paths with dots and spaces, attackers can hide malicious files and processes from the user and system monitoring tools, such as Task Manager and Process Explorer.
2. Archive File Manipulation: Attackers can manipulate archive files to hide their contents. When a victim extracts the archive, the extraction logic is tricked into creating symbolic links instead of the actual files, leading to the execution of the attacker’s payload.
3. Misrepresentation of Files: The vulnerability can be used to make malware files appear as verified executables published by Microsoft, deceiving users and potentially bypassing security measures.
4. Denial of Service (DoS): Attackers can disable Process Explorer by exploiting a DoS vulnerability, hindering the victim’s ability to analyze and detect malicious activity.

Rootkit-like Abilities

The MagicDot vulnerability grants attackers abilities akin to a rootkit, which is a type of malware designed to gain unauthorized root or administrative access to a computer while remaining hidden:

Stealth: The ability to hide files, directories, and processes from both users and system monitoring tools.

Anti-Analysis: Techniques to disable or mislead analysis tools like Process Explorer, making it difficult for users or administrators to detect the presence of malware.

Persistence: By hiding malicious processes and files, attackers can maintain a persistent presence on the system without detection.

Researchers disclosed findings to Microsoft, as noted above. Microsoft did address the vulnerabilities, but has decided to leave the DOS-to-NT path conversion known issue unfixed.

• Remote Code Execution (CVE-2023-36396, CVSS: 7.8): The vulnerability was confirmed, reproduced, and fixed by Microsoft. It was assessed as an RCE with an “Important” severity.
• Elevation of Privilege (Write) (CVE-2023-32054, CVSS: 7.3): The vulnerability was confirmed, reproduced, and fixed by Microsoft. It was assessed as a privilege elevation (PE) with an “Important” severity.
• Elevation of Privilege (Deletion): The vulnerability was reproduced and confirmed by Microsoft. However, they did not issue a CVE or a fix, but instead provided the following response: “Thank you again for submitting this issue to Microsoft. We determined that this issue does not require immediate security service but did reveal unexpected behavior. A fix for this issue will be considered in a future version of this product or service.”
• Process Explorer Unprivileged DOS for Anti-Analysis (CVE-2023-42757): The vulnerability was reproduced, confirmed, and fixed by the engineering team of Process Explorer in version 17.04. CVE-2023-42757 was reserved for this vulnerability by MITRE. MITRE confirmed the vulnerability with Microsoft and will publish the CVE once online publication of the details is available.