CVE-2002-0516 in SquirrelMail
Summary
by MITRE
SquirrelMail 1.2.5 and earlier allows authenticated SquirrelMail users to execute arbitrary commands by modifying the THEME variable in a cookie.
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Analysis
by VulDB Data Team • 09/16/2025
The vulnerability identified as CVE-2002-0516 represents a critical command injection flaw within SquirrelMail version 1.2.5 and earlier installations. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before incorporating it into system operations. The vulnerability specifically targets the THEME variable within user cookies, which are typically used to customize the webmail interface appearance. When authenticated users manipulate this cookie value, the application processes the modified theme parameter without sufficient sanitization, creating an opportunity for malicious command execution.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP cookies that store user preferences, particularly the THEME variable. When SquirrelMail processes these cookie values, it fails to validate or sanitize the input before using it in system calls or file operations. This oversight allows attackers to inject malicious commands that get executed with the privileges of the web server process. The flaw essentially enables a form of parameter pollution where user-controllable input directly influences the application's command execution flow, bypassing normal access controls and authentication mechanisms.
From an operational perspective, this vulnerability significantly impacts organizations relying on SquirrelMail for email services, as it provides authenticated attackers with the capability to execute arbitrary code on the affected server. The implications extend beyond simple data theft, as successful exploitation could lead to complete system compromise, data exfiltration, and potential lateral movement within the network. The vulnerability is particularly dangerous because it requires only authentication to the SquirrelMail application, which is typically accessible to legitimate users, making it difficult to detect and prevent. This weakness directly aligns with CWE-74, which describes improper neutralization of special elements in output used by a downstream component, and CWE-94, which addresses the execution of code from external inputs.
The attack surface for this vulnerability is relatively narrow but impactful, as it requires an authenticated session to the SquirrelMail interface. However, the potential for privilege escalation and system compromise makes it a serious concern for organizations with webmail deployments. The vulnerability demonstrates poor input validation practices and highlights the importance of secure coding principles in web applications. Organizations should consider implementing proper cookie validation, sanitization of user inputs, and principle of least privilege configurations to mitigate such risks. The flaw also relates to ATT&CK technique T1059, which involves executing commands through various interfaces, and T1133, which focuses on persistence mechanisms through web applications. Immediate remediation efforts should include upgrading to patched versions of SquirrelMail, implementing web application firewalls, and conducting thorough security assessments of webmail implementations to identify similar vulnerabilities in other components.