CVE-2017-11503 in PHPMailer
Summary
by MITRE
PHPMailer 5.2.23 has XSS in the "From Email Address" and "To Email Address" fields of code_generator.php.
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Analysis
by VulDB Data Team • 12/13/2022
PHPMailer version 5.2.23 contains a cross-site scripting vulnerability in the code_generator.php file that affects the "From Email Address" and "To Email Address" fields. This vulnerability arises from insufficient input validation and output escaping mechanisms within the code generation functionality. The flaw allows attackers to inject malicious javascript code through email address fields that are subsequently rendered in the generated code without proper sanitization. When a victim visits the page containing the generated code, the malicious script executes in their browser context, potentially leading to session hijacking, data theft, or further exploitation. The vulnerability is particularly concerning because it leverages the legitimate code generation feature of PHPMailer, making it more difficult to detect and mitigate. This issue falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security. The attack surface is broad as any user who can access the code generator interface and submit email addresses can potentially exploit this vulnerability. According to ATT&CK framework, this represents a technique categorized under T1566 - Phishing, where attackers can use the XSS vulnerability to deliver malicious payloads through email address fields. The impact extends beyond simple script execution as it can be combined with other techniques to perform more sophisticated attacks including credential theft, cookie manipulation, and redirection to malicious sites. The vulnerability exists because the application fails to properly escape special characters in email addresses before incorporating them into generated html code. This lack of proper sanitization creates an opening for attackers to inject javascript payloads that execute in the context of other users who view the generated code. Organizations using PHPMailer 5.2.23 should immediately upgrade to a patched version or implement proper input validation and output escaping measures. The recommended mitigation includes implementing strict input validation for email address formats, applying html entity encoding to all user-supplied data before rendering, and ensuring that the code generation functionality properly sanitizes all inputs. Additionally, network segmentation and web application firewalls can provide additional layers of protection against exploitation attempts. The vulnerability demonstrates the critical importance of input validation in web applications and highlights how seemingly benign features can become attack vectors when proper security controls are not implemented. This issue underscores the need for comprehensive security testing including dynamic analysis and input validation reviews to identify similar vulnerabilities in other components of the application stack.