CVE-2018-7717 in Simple Image Gallery Extended
Summary
by MITRE
The htmlImageAddTitleAttribute function in sige.php in the Kubik-Rubik Simple Image Gallery Extended (SIGE) extension 3.2.3 for Joomla! has XSS via a crafted image header, as demonstrated by the Caption-Abstract header object in a JPEG file. This is fixed in 3.3.1.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 01/10/2020
The vulnerability CVE-2018-7717 represents a cross-site scripting flaw in the Kubik-Rubik Simple Image Gallery Extended extension for Joomla!, specifically within the htmlImageAddTitleAttribute function in the sige.php file. This issue affects version 3.2.3 and demonstrates how image metadata handling can introduce security risks into web applications. The vulnerability arises from insufficient input validation and sanitization of image header data, particularly when processing JPEG files that contain crafted metadata structures.
The technical exploitation occurs through manipulation of image header objects, specifically targeting the Caption-Abstract header found in JPEG files. When the SIGE extension processes these images, it fails to properly sanitize or escape the metadata content before incorporating it into HTML output. This creates an opportunity for attackers to inject malicious JavaScript code or other harmful content that executes in the context of users viewing the affected gallery. The vulnerability is classified under CWE-79 as a failure to sanitize user input before incorporating it into web output, making it a classic cross-site scripting vector. The attack vector is particularly concerning because it leverages legitimate image processing functionality rather than requiring direct code injection into the application's core.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, defacement of gallery content, or redirection to malicious sites. Users accessing galleries with vulnerable extensions become potential victims of phishing attacks or credential theft attempts. The vulnerability is particularly dangerous in environments where administrators may not be aware that image metadata can contain malicious payloads, as the attack occurs at the image processing layer rather than through traditional web application attack vectors. This weakness can be exploited in conjunction with other techniques to establish persistent access or escalate privileges within the Joomla! environment.
Mitigation strategies for CVE-2018-7717 involve immediate upgrading to version 3.3.1 or later, which contains the necessary patches to address the sanitization issues in the htmlImageAddTitleAttribute function. Organizations should also implement comprehensive input validation for all image metadata processing, including the implementation of Content Security Policies to limit script execution in gallery contexts. Security monitoring should include detection of suspicious image metadata patterns and regular vulnerability assessments of third-party extensions. The ATT&CK framework categorizes this vulnerability under T1059.007 for script injection techniques, highlighting the need for proper output encoding and input validation as defensive measures. Additionally, administrators should consider implementing web application firewalls to detect and block suspicious metadata injection attempts, while maintaining regular updates to all Joomla! extensions to prevent similar vulnerabilities from being exploited in the future.