CVE-2006-5449 in Ingo H3
Summary
by MITRE
procmail in Ingo H3 before 1.1.2 Horde module allows remote authenticated users to execute arbitrary commands via shell metacharacters in the mailbox destination of a filter rule.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability identified as CVE-2006-5449 represents a critical command injection flaw within the procmail component of the Ingo H3 Horde module version 1.1.1 and earlier. This issue affects web-based email filtering systems that utilize procmail as their underlying mail delivery mechanism, creating a significant security risk for organizations relying on Horde's email management capabilities. The vulnerability specifically targets the mailbox destination field within filter rules, where user input is improperly sanitized before being processed by the system.
The technical exploitation of this vulnerability occurs through the manipulation of shell metacharacters within the mailbox destination parameter of email filter configurations. When authenticated users create or modify filter rules, they can inject malicious shell commands that will be executed with the privileges of the procmail process. This occurs because the application fails to properly escape or validate user-supplied input before incorporating it into shell commands that are subsequently executed by the system. The flaw essentially allows attackers to bypass normal access controls and execute arbitrary code on the affected server, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple command execution, as it can enable attackers to gain persistent access to email servers and potentially escalate privileges to root level access. Attackers can leverage this vulnerability to establish backdoors, exfiltrate sensitive email data, modify email routing configurations, or even deploy additional malware within the compromised environment. The authenticated nature of the exploit means that attackers must first gain valid user credentials, but this requirement does not significantly mitigate the risk given that many email systems have weak authentication mechanisms or users may reuse credentials across multiple systems. This vulnerability aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and represents a classic example of command injection attacks that are frequently exploited in web application security breaches.
Organizations affected by this vulnerability should implement immediate mitigations including updating to Ingo H3 version 1.1.2 or later, which contains the necessary patches to address the input sanitization issues. System administrators should also consider implementing additional security controls such as restricting user privileges when creating filter rules, implementing input validation at multiple layers, and monitoring for suspicious command executions within email processing systems. Network segmentation and intrusion detection systems should be configured to monitor for unusual patterns of command execution that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and output encoding in preventing command injection attacks, aligning with ATT&CK technique T1059.001 for command and script injection. Organizations should also conduct comprehensive security assessments to identify other potential command injection vulnerabilities within their email infrastructure and ensure that all third-party applications undergo regular security reviews to prevent similar issues from arising in the future.