CVE-2018-11780 in SpamAssassin
Summary
by MITRE
A potential Remote Code Execution bug exists with the PDFInfo plugin in Apache SpamAssassin before 3.4.2.
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Analysis
by VulDB Data Team • 05/16/2023
The vulnerability CVE-2018-11780 represents a critical remote code execution flaw within the PDFInfo plugin of Apache SpamAssassin versions prior to 3.4.2. This issue arises from improper input validation and sanitization mechanisms within the plugin's processing of PDF files, creating a pathway for malicious actors to execute arbitrary code on systems running vulnerable versions of the spam filtering software. The PDFInfo plugin is designed to extract metadata and information from PDF documents as part of the spam detection process, but the vulnerability allows attackers to manipulate this functionality for malicious purposes.
The technical flaw manifests through insufficient validation of user-supplied input when processing PDF files within the plugin's code execution flow. Attackers can craft specially formatted PDF documents that contain malicious payloads which, when processed by the vulnerable PDFInfo plugin, trigger code execution on the target system. This vulnerability falls under CWE-74 which describes "Improper Neutralization of Special Elements in Output Used by a Downstream Component," specifically in the context of command injection. The flaw enables attackers to bypass normal security controls and execute arbitrary commands with the privileges of the SpamAssassin process, potentially leading to full system compromise.
The operational impact of this vulnerability is severe for organizations relying on Apache SpamAssassin for email filtering and security. Systems running vulnerable versions become susceptible to remote exploitation without requiring authentication, making them attractive targets for automated attacks. The vulnerability affects the core functionality of spam detection and filtering, potentially allowing attackers to bypass security measures entirely while simultaneously gaining unauthorized access to the underlying system. This creates a significant risk for email servers, corporate networks, and organizations that depend on SpamAssassin for protecting against spam and malicious email content. The attack surface extends to any system that processes PDF attachments through the vulnerable plugin, including email gateways, web applications, and file processing systems.
Organizations should immediately upgrade to Apache SpamAssassin version 3.4.2 or later to remediate this vulnerability. The upgrade process should include thorough testing of the updated configuration to ensure continued proper functionality of spam filtering operations. Additional mitigations include implementing network segmentation to limit access to systems running SpamAssassin, disabling the PDFInfo plugin if PDF processing is not essential for spam detection, and monitoring for suspicious activity related to email processing. Security teams should also consider implementing web application firewalls and network intrusion detection systems to monitor for exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, and T1190 for Exploit Public-Facing Application, making it a significant concern for enterprise security operations. Regular vulnerability assessments and patch management processes should be strengthened to prevent similar issues in other components of the email security infrastructure.