CVE-2021-24291 in Mobile-Friendly Image Gallery Plugin
Summary
by MITRE • 05/14/2021
The Photo Gallery by 10Web – Mobile-Friendly Image Gallery WordPress plugin before 1.5.69 was vulnerable to Reflected Cross-Site Scripting (XSS) issues via the gallery_id, tag, album_id and _id GET parameters passed to the bwg_frontend_data AJAX action (available to both unauthenticated and authenticated users)
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Analysis
by VulDB Data Team • 05/19/2021
The Photo Gallery by 10Web WordPress plugin suffered from a critical reflected cross-site scripting vulnerability that affected versions prior to 1.5.69. This vulnerability exploited the plugin's handling of user-supplied input through specific GET parameters within the bwg_frontend_data AJAX endpoint. The flaw was particularly concerning because it could be exploited by both unauthenticated and authenticated users, significantly expanding the potential attack surface. The vulnerable parameters included gallery_id, tag, album_id, and _id which were directly incorporated into the plugin's response without proper sanitization or encoding, creating an avenue for malicious script execution in the context of a victim's browser.
The technical implementation of this vulnerability stemmed from insufficient input validation and output encoding practices within the plugin's AJAX handler. When users accessed the bwg_frontend_data endpoint with malicious payloads in the specified GET parameters, the plugin failed to properly sanitize these inputs before returning them in the HTTP response. This reflected XSS condition allowed attackers to inject malicious JavaScript code that would execute in the browser context of any user who viewed the affected page or clicked on a malicious link. The vulnerability was classified as CWE-79 - Improper Neutralization of Input During Web Page Generation, which represents one of the most common and dangerous web application security flaws.
The operational impact of this vulnerability was substantial as it enabled attackers to perform various malicious activities including session hijacking, credential theft, defacement of gallery content, and redirection to malicious websites. An attacker could craft a malicious URL containing XSS payloads and send it to unsuspecting users through phishing campaigns or social engineering tactics. Once a victim clicked the malicious link, the injected scripts would execute in their browser, potentially stealing cookies, modifying gallery displays, or redirecting users to attacker-controlled domains. The vulnerability's accessibility to both authenticated and unauthenticated users meant that even casual visitors to a website using the vulnerable plugin could be compromised, making the attack vector particularly dangerous.
Mitigation strategies for this vulnerability required immediate patching of the plugin to version 1.5.69 or later, which contained proper input sanitization and output encoding mechanisms. System administrators should implement comprehensive input validation for all user-supplied parameters, particularly those used in AJAX endpoints and dynamic content generation. The implementation of Content Security Policy headers could provide additional protection against XSS attacks by restricting script execution and limiting the sources from which scripts could be loaded. Regular security auditing of WordPress plugins and themes, along with maintaining updated security practices such as principle of least privilege and input/output encoding, would help prevent similar vulnerabilities in the future. Organizations should also consider implementing web application firewalls and monitoring for suspicious parameter usage patterns to detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as it could be exploited through malicious links delivered via phishing campaigns, and T1213.002 - Data from Information Repositories: Web Applications, as it targets web application interfaces that store and serve user-generated content.