CVE-2024-28054 is a vulnerability in Amavis, an open-source content filter used primarily for email scanning and malware detection. The issue stems from an interpretation conflict related to MIME message parsing, specifically when multiple boundary parameters are present in a MIME email. Amavis relies on MIME-tools for parsing MIME structures, but due to this conflict, it may incorrectly interpret the boundaries, leading to improper scanning of email parts. This can result in banned files or malware being overlooked during the scanning process, effectively allowing malicious payloads to bypass Amavis's filtering mechanisms. The vulnerability affects Amavis versions prior to 2.12.3 and 2.13.x versions before 2.13.1. The CVSS v3.1 score is 7.4, indicating high severity, with an attack vector of network (remote exploitation possible), high attack complexity, no privileges required, no user interaction, and impacts on confidentiality and integrity but not availability. Although no exploits are currently known in the wild, the flaw poses a significant risk to email security, as attackers could craft MIME emails with multiple boundary parameters to evade detection. This vulnerability is categorized under CWE-436 (Interpretation Conflict).

For European organizations, the impact of CVE-2024-28054 can be substantial, particularly for those relying on Amavis as part of their email security infrastructure. Successful exploitation could allow malware, ransomware, or other malicious attachments to bypass email scanning, increasing the risk of infection, data breaches, or lateral movement within networks. Confidentiality could be compromised if sensitive information is exfiltrated via malicious emails that evade detection. Integrity of email content and filtering policies could be undermined, leading to trust issues and potential regulatory non-compliance under GDPR if malware leads to data loss or exposure. The absence of known exploits in the wild provides a window for proactive mitigation, but the high severity score underscores the urgency. Organizations with high email volumes and critical communications, such as financial institutions, healthcare providers, and government agencies, face elevated risks.

1. Upgrade Amavis to version 2.12.3 or later, or 2.13.1 or later, as soon as these patched versions become available to address the MIME boundary parsing issue. 2. Until patches are applied, implement additional email security layers such as sandboxing suspicious attachments, deploying alternative or complementary email scanning solutions, or using advanced threat protection services that do not rely solely on Amavis. 3. Monitor email logs for unusual MIME boundary usage or suspicious email patterns that could indicate exploitation attempts. 4. Conduct regular security awareness training for staff to recognize phishing and malicious email indicators, reducing the risk of successful payload execution. 5. Employ network-level protections such as intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous email traffic. 6. Maintain up-to-date backups and incident response plans to quickly recover from potential malware infections that bypass email filters. 7. Engage with vendors and open-source communities for timely updates and advisories related to Amavis and MIME-tools.