Description
A vulnerability in the PDF scanning processes of ClamAV could allow an unauthenticated, remote attacker to cause a buffer overflow condition, cause a denial of service (DoS) condition, or execute arbitrary code on an affected device. This vulnerability exists because memory buffers are allocated incorrectly when PDF files are processed. An attacker could exploit this vulnerability by submitting a crafted PDF file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to trigger a buffer overflow, likely resulting in the termination of the ClamAV scanning process and a DoS condition on the affected software. Although unproven, there is also a possibility that an attacker could leverage the buffer overflow to execute arbitrary code with the privileges of the ClamAV process.
EPSS Score:
0%
Comprehensive Technical Analysis of EUVD-2025-18658
1. Vulnerability Assessment and Severity Evaluation
The vulnerability in the PDF scanning processes of ClamAV, identified as EUVD-2025-18658 (CVE-2025-20260), is critical due to its potential to cause a buffer overflow condition. This can lead to a denial of service (DoS) or, in the worst case, arbitrary code execution. The CVSS (Common Vulnerability Scoring System) base score of 9.8 indicates a high severity level, primarily due to the following factors:
- Attack Vector (AV:N): The vulnerability can be exploited over the network.
- Attack Complexity (AC:L): The attack requires low complexity.
- Privileges Required (PR:N): No privileges are required to exploit the vulnerability.
- User Interaction (UI:N): No user interaction is required.
- Scope (S:U): The vulnerability does not change the security scope.
- Confidentiality (C:H): High impact on confidentiality.
- Integrity (I:H): High impact on integrity.
- Availability (A:H): High impact on availability.
2. Potential Attack Vectors and Exploitation Methods
The primary attack vector involves submitting a crafted PDF file to be scanned by ClamAV. An attacker could exploit this vulnerability through the following methods:
- Email Attachments: Sending a malicious PDF file as an email attachment to a system that uses ClamAV for scanning.
- Web Uploads: Uploading a crafted PDF file to a web application that uses ClamAV to scan uploaded files.
- Network Shares: Placing a malicious PDF file on a network share that is scanned by ClamAV.
The buffer overflow condition can be triggered by the incorrect allocation of memory buffers during the PDF processing, potentially leading to arbitrary code execution with the privileges of the ClamAV process.
3. Affected Systems and Software Versions
The vulnerability affects multiple versions of ClamAV, including:
- ClamAV 1.4.0
- ClamAV 1.3.2
- ClamAV 1.3.0
- ClamAV 1.4.1
- ClamAV 1.4.2
- ClamAV 1.2.1
- ClamAV 1.2.2
- ClamAV 1.2.3
- ClamAV 1.2.0
- ClamAV 1.3.1
Organizations using any of these versions are at risk and should prioritize updating to a patched version.
4. Recommended Mitigation Strategies
To mitigate the risk associated with this vulnerability, the following strategies are recommended:
- Patch Management: Immediately update ClamAV to the latest patched version. Cisco has released a security patch for ClamAV versions 1.4.3 and 1.0.9.
- Input Validation: Implement strict input validation for PDF files before they are processed by ClamAV.
- Network Segmentation: Segment networks to limit the exposure of critical systems to potentially malicious PDF files.
- Monitoring and Logging: Enhance monitoring and logging to detect and respond to suspicious activities related to PDF file processing.
- User Awareness: Educate users about the risks associated with opening and uploading PDF files from untrusted sources.
5. Impact on European Cybersecurity Landscape
The vulnerability poses a significant risk to European organizations that rely on ClamAV for antivirus protection. Given the widespread use of ClamAV in various sectors, including government, healthcare, and finance, the potential impact is substantial. A successful exploit could lead to data breaches, service disruptions, and unauthorized access to sensitive information.
6. Technical Details for Security Professionals
Vulnerability Details:
- Root Cause: Incorrect memory buffer allocation during PDF file processing.
- Exploitation: Crafted PDF files can trigger a buffer overflow, leading to DoS or arbitrary code execution.
- Detection: Monitor for unusual ClamAV process terminations and investigate any suspicious PDF files.
- Response: Implement incident response plans to quickly identify and mitigate any exploitation attempts.
References:
Conclusion: The vulnerability in ClamAV's PDF scanning processes is a critical concern for organizations using affected versions. Immediate patching and implementation of robust mitigation strategies are essential to protect against potential exploits. The European cybersecurity landscape must remain vigilant and proactive in addressing such vulnerabilities to safeguard against significant security incidents.