CVE-2016-10508 in phpThumb
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in phpThumb() before 1.7.14 allow remote attackers to inject arbitrary web script or HTML via parameters in demo/phpThumb.demo.showpic.php.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2016-10508 represents a critical cross-site scripting weakness affecting the phpThumb() library version 1.7.13 and earlier. This flaw resides within the demo/phpThumb.demo.showpic.php component where user-supplied parameters are inadequately sanitized before being rendered in web responses. The vulnerability enables remote attackers to inject malicious scripts or HTML code that executes in the context of victims' browsers, potentially leading to session hijacking, credential theft, or further exploitation of the affected systems. The issue stems from insufficient input validation and output encoding practices within the demonstration script that processes image thumbnail generation requests. This vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws as weaknesses in input validation and output encoding mechanisms. The ATT&CK framework would classify this as a web application vulnerability exploitation technique under the T1190 category for exploit public-facing applications, with potential for T1566 targeting credential access through session manipulation.
The technical exploitation of this vulnerability occurs when attackers manipulate parameters passed to the demo script, specifically targeting the image processing functionality. The phpThumb() library typically handles image manipulation tasks by processing parameters such as image source URLs, dimensions, and formatting options. When these parameters are not properly validated or encoded, malicious payloads can be injected and subsequently executed when the demo page renders the processed image information. Attackers can craft URLs containing script tags or other malicious content that gets embedded into the page output, creating a persistent XSS vector. The vulnerability affects the demonstration environment rather than the core library functionality, making it particularly dangerous in development or testing environments where the demo scripts are accessible to unauthorized users. This makes the vulnerability exploitable in scenarios where demo functionality is exposed to external users or where administrative access to the demo script is compromised.
The operational impact of CVE-2016-10508 extends beyond immediate script execution capabilities to encompass broader security implications for web applications utilizing the phpThumb library. Successful exploitation can result in unauthorized access to user sessions, data exfiltration, and potential privilege escalation within the application context. The vulnerability creates a persistent threat vector that can be leveraged to establish backdoors, redirect users to malicious sites, or harvest sensitive information from authenticated sessions. Organizations using vulnerable versions of phpThumb may experience compromised user trust, regulatory compliance violations, and potential legal consequences due to inadequate security controls. The demonstration script serves as an attack surface that could be exploited to gain initial access to systems before targeting the actual image processing functionality. This makes the vulnerability particularly concerning for environments where the demo interface is accessible without proper authentication controls or where administrators may inadvertently expose development components to production environments.
The recommended mitigation strategy involves immediate upgrade to phpThumb version 1.7.14 or later, which contains the necessary patches to address the XSS vulnerabilities. Organizations should also implement proper input validation and output encoding mechanisms for all user-supplied parameters, particularly in demonstration environments. Security configurations should restrict access to demo scripts and ensure that only authorized personnel can interact with development components. Additional protective measures include implementing content security policies, regular security assessments, and monitoring for suspicious parameter usage patterns. The vulnerability demonstrates the importance of securing all application components, including demonstration scripts, and highlights the need for comprehensive input validation across all user-facing interfaces. Organizations should conduct thorough vulnerability assessments to identify other potential XSS vectors within their applications and ensure that security practices align with industry standards such as those defined in the OWASP Top Ten and NIST cybersecurity frameworks.