CVE-2003-0990 in SquirrelMail
Summary
by MITRE
The parseAddress code in (1) SquirrelMail 1.4.0 and (2) GPG Plugin 1.1 allows remote attackers to execute commands via shell metacharacters in the "To:" field.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2003-0990 represents a critical command injection flaw within the SquirrelMail email client and its GPG Plugin component. This security weakness exists in the parseAddress function which processes email addresses submitted through the "To:" field of email messages. The vulnerability stems from inadequate input validation and sanitization of user-supplied data, allowing malicious actors to inject shell metacharacters that get executed by the underlying system. The affected versions include SquirrelMail 1.4.0 and GPG Plugin 1.1, both of which were widely deployed email solutions in the early 2000s.
The technical implementation of this vulnerability involves the improper handling of email address parsing within the SquirrelMail application. When users compose emails and enter addresses in the "To:" field, the parseAddress function processes these inputs without sufficient sanitization measures. Attackers can exploit this by embedding shell metacharacters such as semicolons, ampersands, or backticks directly into the email address field. These characters are then interpreted by the system's shell commands, leading to arbitrary command execution with the privileges of the web server process. This type of vulnerability falls under CWE-78, which specifically addresses "Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')", making it a direct implementation of this well-known weakness category.
The operational impact of this vulnerability is severe and far-reaching for organizations utilizing affected versions of SquirrelMail. Remote attackers can execute arbitrary commands on the affected web server, potentially leading to complete system compromise, data exfiltration, or unauthorized access to sensitive email communications. The vulnerability is particularly dangerous because it requires no authentication to exploit, making it an ideal candidate for automated attacks. Attackers can leverage this weakness to gain persistent access to email servers, escalate privileges, or use the compromised system as a launch point for further attacks within the network infrastructure. This vulnerability directly aligns with ATT&CK technique T1059.001, which describes "Command and Scripting Interpreter: PowerShell" and similar execution methods, though the specific implementation here uses shell metacharacters rather than PowerShell.
Mitigation strategies for CVE-2003-0990 require immediate patching of affected systems to the latest stable versions of SquirrelMail and GPG Plugin. Organizations should implement input validation and sanitization measures at multiple layers, including filtering special characters from email address fields and employing proper escaping mechanisms before any shell commands are executed. Network segmentation and firewall rules can help limit the attack surface, while monitoring systems should be configured to detect unusual command execution patterns. The vulnerability also highlights the importance of regular security assessments and the need for robust application security practices including input validation, output encoding, and principle of least privilege implementation. Additionally, administrators should consider implementing web application firewalls to detect and block malicious payloads targeting similar command injection vulnerabilities.