CVE-2025-8351

Comprehensive Technical Analysis of CVE-2025-8351

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2025-8351 Description: This vulnerability involves a heap-based buffer overflow and out-of-bounds read in Avast Antivirus on macOS. The issue arises when the antivirus engine scans a malformed file, potentially leading to local execution of arbitrary code or a denial-of-service (DoS) condition.

CVSS Score: 9 Severity: Critical

The high CVSS score of 9 indicates that this vulnerability poses a significant risk. The potential for code execution and DoS attacks makes it a high-priority issue for immediate attention.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Malformed File Scanning: An attacker could craft a malicious file designed to exploit the buffer overflow vulnerability when scanned by Avast Antivirus.
• Local Access: Since the vulnerability requires local access to exploit, an attacker would need to have physical or remote access to the target system.

Exploitation Methods:

• Heap-based Buffer Overflow: By carefully crafting a file that overflows the heap buffer, an attacker can inject malicious code into the memory space of the antivirus process.
• Out-of-bounds Read: Exploiting the out-of-bounds read can lead to information disclosure or further manipulation of the program's execution flow.

3. Affected Systems and Software Versions

Affected Software: Avast Antivirus for macOS Versions Affected: From 8.3.70.94 to before 8.3.70.98

Users running Avast Antivirus within the specified version range on macOS are at risk and should update to the latest version immediately.

4. Recommended Mitigation Strategies

Immediate Actions:

• Update Software: Ensure that all systems running Avast Antivirus on macOS are updated to version 8.3.70.98 or later.
• Disable Automatic Scanning: Temporarily disable automatic scanning of files until the update is applied.

Long-term Strategies:

• Regular Patch Management: Implement a robust patch management program to ensure all software is kept up-to-date.
• User Education: Educate users on the risks of running outdated software and the importance of timely updates.
• Network Segmentation: Segment networks to limit the spread of potential threats and reduce the attack surface.

5. Impact on Cybersecurity Landscape

Immediate Impact:

• Increased Risk: Organizations and individuals using the affected versions of Avast Antivirus on macOS are at increased risk of local code execution and DoS attacks.
• Reputation: The vulnerability could impact the perceived reliability and security of Avast Antivirus, potentially leading users to seek alternative solutions.

Long-term Impact:

• Enhanced Security Measures: This incident may prompt antivirus vendors to enhance their security measures and improve their code review processes.
• User Awareness: Increased awareness among users about the importance of keeping security software up-to-date.

6. Technical Details for Security Professionals

Vulnerability Details:

• Heap-based Buffer Overflow: This type of vulnerability occurs when a program writes more data to a buffer located in the heap than is actually allocated for that buffer. This can lead to corruption of data, crashes, or execution of arbitrary code.
• Out-of-bounds Read: This occurs when a program reads data from outside the bounds of allocated memory, potentially leading to information disclosure or unintended behavior.

Exploitation:

• Crafting Malformed Files: Attackers can create specially crafted files that, when scanned by the vulnerable antivirus engine, trigger the buffer overflow and out-of-bounds read.
• Code Injection: By injecting malicious code into the heap, attackers can execute arbitrary commands with the privileges of the antivirus process.

Detection and Response:

• Monitoring: Implement monitoring for unusual antivirus process behavior, such as unexpected crashes or high CPU usage.
• Incident Response: Have an incident response plan in place to quickly address any detected exploitation attempts.

Conclusion: CVE-2025-8351 represents a critical vulnerability in Avast Antivirus for macOS that requires immediate attention. By understanding the technical details and implementing the recommended mitigation strategies, organizations can protect themselves from potential exploitation and maintain a robust cybersecurity posture.