CVE-2013-4479 in sup
Summary
by MITRE
lib/sup/message_chunks.rb in Sup before 0.13.2.1 and 0.14.x before 0.14.1.1 allows remote attackers to execute arbitrary commands via shell metacharacters in the content_type of an email attachment.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-4479 affects the Sup email client software, specifically targeting versions prior to 0.13.2.1 and 0.14.x versions before 0.14.1.1. This represents a critical command execution flaw that arises from improper input validation within the message_chunks.rb component of the application's codebase. The vulnerability manifests when the application processes email attachments, particularly focusing on the content_type parameter of these attachments.
The technical flaw stems from insufficient sanitization of user-supplied data within the email processing pipeline. When Sup receives email messages containing attachments, it parses the content_type field without adequate filtering or escaping of special shell metacharacters. This oversight creates a path for remote attackers to inject malicious commands that get executed within the context of the application's processing environment. The vulnerability falls under the category of command injection as defined by CWE-77, where attacker-controlled data flows into a command invocation function without proper validation or sanitization.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary commands on the system running the Sup email client. An attacker could potentially gain full control over the affected system, including the ability to read, modify, or delete files, establish persistence mechanisms, or even escalate privileges. The attack vector requires only that an attacker send a specially crafted email with a malicious content_type field, making this vulnerability particularly dangerous in environments where users regularly receive emails from untrusted sources. This type of vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically focusing on the execution of commands through shell injection.
The vulnerability demonstrates poor input validation practices that violate fundamental security principles. The application fails to implement proper sanitization or escaping of special characters that could be interpreted by the shell during command execution. This flaw represents a classic example of how insufficient data validation can lead to severe security consequences. Organizations using Sup email client software are at risk of unauthorized access and potential system compromise, particularly in environments where email is the primary communication channel and where the application runs with elevated privileges.
Mitigation strategies for this vulnerability include immediate patching of the Sup email client to versions 0.13.2.1 or 0.14.1.1, which contain the necessary fixes to properly sanitize the content_type parameter. Administrators should also implement email filtering solutions that can detect and block suspicious content_type headers in incoming emails. Network-level controls such as email gateway filtering and intrusion prevention systems can provide additional layers of protection. The vulnerability highlights the importance of implementing secure coding practices including input validation, output encoding, and proper command construction techniques. Organizations should also consider implementing principle of least privilege for email processing applications and regular security assessments to identify similar vulnerabilities in their software infrastructure.