CVE-2025-7007: Avast Antivirus DoS Vulnerability

CVE-2025-7007 Overview

A NULL Pointer Dereference vulnerability has been identified in Avast Antivirus affecting both MacOS and Linux platforms. The vulnerability is triggered when the antivirus engine scans a malformed Windows Portable Executable (PE) file, resulting in a crash of the antivirus process. This denial of service condition could allow attackers to disable security protections by crafting malicious PE files that exploit the parsing flaw.

Critical Impact

Attackers can crash the Avast Antivirus process by delivering malformed Windows PE files, potentially disabling endpoint protection and leaving systems vulnerable to further attacks.

Affected Products

• Avast Antivirus on MacOS version 16.0.0
• Avast Antivirus on Linux version 3.0.3

Discovery Timeline

• 2025-12-01 - CVE-2025-7007 published to NVD
• 2025-12-02 - Last updated in NVD database

Technical Details for CVE-2025-7007

Vulnerability Analysis

This vulnerability is classified as CWE-476 (NULL Pointer Dereference) and carries a HIGH severity rating with a CVSS 3.1 score of 7.5. The CVSS vector CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H indicates a local attack vector requiring high attack complexity, low privileges, and user interaction, with potential for scope change and high impact across confidentiality, integrity, and availability.

The vulnerability resides in the PE file parsing component of the Avast Antivirus scanning engine. When processing Windows PE files, the parser fails to properly validate certain header structures, leading to a NULL pointer being dereferenced during the scanning operation.

The EPSS (Exploit Prediction Scoring System) probability is 0.013% with a percentile of 1.617, indicating a relatively low likelihood of exploitation in the wild at this time.

Root Cause

The root cause lies in insufficient validation of PE file header fields during the parsing phase. When the antivirus scanner encounters a malformed PE file with specific invalid or missing header structures, the parsing logic attempts to access memory through a pointer that has not been properly initialized, resulting in a NULL pointer dereference condition.

Attack Vector

The attack vector is local, meaning an attacker would need to deliver the malformed PE file to a system where Avast Antivirus is installed. This could be accomplished through various means:

• Email attachments that trigger on-access scanning
• Downloaded files from compromised or malicious websites
• Files delivered via removable media
• Network shares containing malicious files

When the antivirus engine performs a scan on the malformed PE file—either through real-time protection, scheduled scans, or manual scanning—the NULL pointer dereference is triggered, causing the antivirus process to crash.

The vulnerability mechanism involves malformed Windows PE file headers that cause the scanner to attempt dereferencing a NULL pointer during the parsing operation. For technical details on the specific malformations that trigger this condition, refer to the vendor's security advisory at Gen Digital Security Advisories.

Detection Methods for CVE-2025-7007

Indicators of Compromise

• Unexpected crashes or restarts of Avast Antivirus processes on MacOS or Linux systems
• Windows PE files with malformed headers present on affected systems
• Repeated antivirus service failures during file scanning operations
• System logs showing antivirus process termination with NULL pointer or segmentation fault errors

Detection Strategies

Organizations should monitor for anomalous behavior patterns in their endpoint protection:

1. Process Monitoring: Track Avast Antivirus process stability and watch for unexpected terminations or restarts
2. Log Analysis: Review system logs for crash reports related to the antivirus scanning engine, particularly during PE file operations
3. File Analysis: Scan for PE files with suspicious or malformed header structures that could be designed to exploit this vulnerability
4. Service Health Checks: Implement automated health checks for antivirus services to detect when protection becomes unavailable

Monitoring Recommendations

Deploy centralized logging and monitoring solutions to aggregate antivirus process health data across all endpoints. Configure alerts for:

• Antivirus service crashes exceeding normal baseline
• Multiple crash events in short time periods indicating potential exploitation attempts
• Presence of unusual PE files in standard attack delivery locations (email attachments, downloads folders)

SentinelOne Singularity Platform provides comprehensive endpoint visibility that can detect when third-party security processes become unavailable, alerting security teams to potential denial of service attacks against their defense stack.

How to Mitigate CVE-2025-7007

Immediate Actions Required

• Update Avast Antivirus to the latest patched version as soon as vendor updates become available
• Monitor Gen Digital Security Advisories for official patch releases
• Implement additional layers of endpoint protection to maintain security coverage if the antivirus process crashes
• Configure email gateways and web proxies to scan and filter potentially malicious PE files before they reach endpoints

Patch Information

Gen Digital (parent company of Avast) has acknowledged this vulnerability. Organizations should monitor the official security advisories page for patch availability: Gen Digital Security Advisories

Affected versions:

• Avast Antivirus on MacOS: 16.0.0
• Avast Antivirus on Linux: 3.0.3

Workarounds

Until official patches are available, organizations can implement the following mitigations:

1. Defense in Depth: Deploy additional endpoint protection solutions alongside Avast to ensure continuous coverage if one product experiences a denial of service condition

2. Network-Level Filtering: Implement PE file scanning at network perimeter devices to detect and block malformed files before they reach endpoints

3. Process Monitoring: Configure watchdog services to automatically restart the antivirus process if it crashes, minimizing the window of vulnerability

4. User Awareness: Educate users about the risks of opening files from untrusted sources, particularly executable files and archives containing PE files

Organizations using SentinelOne can leverage the Singularity Platform's autonomous protection capabilities to maintain endpoint security even when third-party antivirus solutions experience service disruptions.