Source: cve@mitre.org
Magento Community Edition and Enterprise Edition before 2.0.10 and 2.1.x before 2.1.2 have XSS via e-mail templates that are mishandled during a preview, aka APPSEC-1503.
Magento e-commerce platforms are vulnerable to Cross-Site Scripting (XSS) attacks due to improper handling of email templates during preview. This allows attackers to inject malicious scripts into the platform, potentially leading to account compromise, data theft, and website defacement by exploiting the vulnerability in the email template preview functionality.
Step 1: Payload Creation: The attacker crafts a malicious email template containing JavaScript code within a vulnerable field (e.g., subject, body). This JavaScript is designed to perform actions like stealing cookies or redirecting users.
Step 2: Template Upload/Modification: The attacker, typically with administrator or editor privileges, uploads or modifies an email template within the Magento admin panel. The malicious JavaScript payload is included in the template.
Step 3: Preview Trigger: The attacker or another user with access to the admin panel triggers the email template preview functionality. This action causes the Magento application to render the email template, including the attacker's injected JavaScript.
Step 4: JavaScript Execution: The browser of the user viewing the preview executes the malicious JavaScript code. This happens because the application fails to properly sanitize or encode the user-supplied data before rendering it in the preview.
Step 5: Exploitation: The injected JavaScript code executes, allowing the attacker to steal session cookies, redirect users to malicious websites, or perform other actions to compromise the user's account or the website itself.
The vulnerability stems from insufficient input validation and output encoding within the email template preview feature. Specifically, the application fails to properly sanitize user-supplied data, such as email subject lines or content, before rendering it within the preview. This allows an attacker to inject malicious JavaScript code into the email template. When a user with sufficient privileges (e.g., an administrator) previews the crafted email template, the injected JavaScript executes within the context of the user's browser, enabling the attacker to steal session cookies, redirect users to phishing sites, or modify the website's content. The root cause is a lack of HTML encoding or escaping of user-controlled variables within the email template preview functionality. The application trusts the user input without proper sanitization, leading to the XSS vulnerability. The specific function responsible for rendering the email template preview is likely the one that processes and displays the email template content, including any user-provided data. The flaw is in the lack of proper sanitization before rendering the user-controlled data.
While no specific APT groups are definitively linked to this specific CVE, the nature of the vulnerability (XSS) makes it attractive to a wide range of attackers, including those seeking to steal credentials, deface websites, or distribute malware. This vulnerability could be used in conjunction with other exploits to achieve a broader compromise. CISA KEV: Not listed.
Monitor web server logs for suspicious activity, such as unusual HTTP requests or attempts to access administrative functions.
Analyze network traffic for unusual JavaScript code execution or redirects originating from the Magento application.
Implement a Web Application Firewall (WAF) with rules to detect and block XSS attacks.
Review email template content for suspicious JavaScript code or HTML tags.
Monitor for changes to email templates, especially those made by users with administrative privileges.
Use a Content Security Policy (CSP) to restrict the execution of JavaScript from untrusted sources.
Upgrade to Magento Community Edition and Enterprise Edition versions 2.0.10 or later, or 2.1.2 or later for the 2.1.x branch.
Implement input validation and output encoding to sanitize user-supplied data before rendering it in email templates.
Use a Content Security Policy (CSP) to restrict the execution of JavaScript from untrusted sources.
Regularly scan the Magento installation for vulnerabilities and apply security patches promptly.
Review and restrict access to the Magento admin panel, limiting the number of users with administrative privileges.
Implement a Web Application Firewall (WAF) to detect and block XSS attacks.