CVE-2003-0615 in Linux
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in start_form() of CGI.pm allows remote attackers to insert web script via a URL that is fed into the form s action parameter.
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Analysis
by VulDB Data Team • 12/26/2024
The CVE-2003-0615 vulnerability represents a classic cross-site scripting flaw within the CGI.pm Perl module, a widely used library for handling web forms and CGI applications. This vulnerability specifically targets the start_form() function which generates HTML form elements, creating a dangerous condition where user-supplied input can be directly embedded into the form action attribute without proper sanitization or encoding. The flaw occurs when the CGI.pm library fails to properly escape special characters in URL parameters that are subsequently used to construct the form action, allowing malicious actors to inject arbitrary JavaScript code that executes in the context of other users' browsers.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the CGI.pm library. When developers pass user-controllable URL parameters directly into the start_form() function, the library does not adequately sanitize these inputs before embedding them into the HTML form action attribute. This creates a situation where an attacker can craft a malicious URL containing JavaScript code within the action parameter, which when processed by the CGI.pm library, gets rendered as executable script within the victim's browser. The vulnerability is particularly concerning because it leverages the fundamental trust relationship between web applications and their users, enabling attackers to execute malicious scripts in the context of legitimate web sessions.
The operational impact of CVE-2003-0615 extends beyond simple script execution, potentially enabling sophisticated attacks such as session hijacking, credential theft, and data exfiltration. Attackers can leverage this vulnerability to steal cookies, redirect users to malicious sites, or inject persistent malicious content that affects all users who interact with the vulnerable application. The vulnerability affects any web application using CGI.pm version 2.85 or earlier, making it particularly dangerous in environments where legacy Perl applications remain in production. The attack surface is broad since form handling is a common function across numerous web applications, and the vulnerability can be exploited through various vectors including direct URL manipulation, email links, or even through compromised third-party services that pass user data to vulnerable applications.
This vulnerability aligns with CWE-79, which describes Cross-Site Scripting flaws, and maps to several ATT&CK techniques including T1566 for spearphishing with embedded attachments and T1059 for command and scripting interpreter. The attack chain typically involves an attacker crafting a malicious URL containing script code within the form action parameter, which when accessed by a victim, executes the malicious script in their browser context. Organizations affected by this vulnerability should implement immediate mitigations including updating to CGI.pm version 2.86 or later, implementing proper input sanitization measures, and deploying content security policies to prevent execution of unauthorized scripts. Additionally, developers should avoid directly passing user-controllable parameters into form generation functions without proper encoding and validation, and implement comprehensive testing procedures to identify similar vulnerabilities in other web application components. The vulnerability serves as a critical reminder of the importance of input validation and output encoding in web application security, particularly in libraries that handle user-generated content and form processing.