CVE-2005-0103 in SquirrelMail
Summary
by MITRE
PHP remote file inclusion vulnerability in webmail.php in SquirrelMail before 1.4.4 allows remote attackers to execute arbitrary PHP code by modifying a URL parameter to reference a URL on a remote web server that contains the code.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2005-0103 represents a critical remote file inclusion flaw in SquirrelMail webmail software versions prior to 1.4.4. This issue stems from improper input validation and sanitization within the webmail.php script, which fails to adequately verify or restrict user-supplied URL parameters. The vulnerability manifests when the application accepts a URL parameter that references external resources without proper validation, creating an avenue for attackers to inject malicious PHP code from remote servers. This type of vulnerability falls under the CWE-98 category, which specifically addresses improper restriction of operations within a blacklisted or restricted file access context. The flaw enables attackers to leverage the web application's trust in legitimate file inclusion mechanisms to execute arbitrary code on the target server.
The technical exploitation of this vulnerability occurs through manipulation of URL parameters that control file inclusion operations within the SquirrelMail application. When a user accesses a specially crafted URL that includes a remote file reference, the webmail.php script processes this input without proper validation, leading to the inclusion and execution of malicious PHP code hosted on external servers. This attack vector operates at the application layer and requires no special privileges or authentication to exploit, making it particularly dangerous for web applications that are publicly accessible. The vulnerability demonstrates a classic lack of input validation and output encoding practices that are fundamental to preventing code injection attacks.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and data breach scenarios. Successful exploitation allows attackers to execute arbitrary commands on the vulnerable server, potentially leading to full system control, data exfiltration, and persistence mechanisms. The attack can result in unauthorized access to email accounts, modification of email content, and establishment of backdoors for continued access. This vulnerability particularly affects organizations relying on SquirrelMail for email services, as it can be exploited to gain unauthorized access to sensitive email communications and user credentials. The impact is amplified by the fact that the vulnerability affects versions prior to 1.4.4, indicating that many older installations would remain vulnerable if not properly updated.
Mitigation strategies for this vulnerability center around immediate patching and implementation of proper input validation controls. Organizations should upgrade to SquirrelMail version 1.4.4 or later, which contains the necessary fixes to address the remote file inclusion flaw. Additionally, implementing proper input validation and sanitization measures within the application code can prevent similar vulnerabilities from occurring in other components. Security measures should include restricting file inclusion operations to local directories only, implementing whitelisting of allowed file sources, and employing proper parameter validation techniques. The vulnerability's classification under ATT&CK technique T1190 indicates it falls within the category of exploitation for code execution, emphasizing the need for robust application security controls and regular security assessments to prevent such critical flaws from being exploited in production environments.