Summary

Vulnerability: Stored DOM XSS via Posts Added to Menu (Persistent Payload Injection)

• Stored Cross-Site Scripting via Unsafe Rendering of Post Entries in Menu Management

Description

The application fails to properly sanitize user-controlled input when adding Posts to navigation menus through the Menu Management functionality. Post-related data selected via the Posts section is stored server-side and rendered without proper output encoding.

These stored values are later rendered unsafely within administrative dashboards and public-facing navigation menus, resulting in stored DOM-based cross-site scripting (XSS).

Affected Functionality

• Menu Management – Posts section
• Adding posts to navigation menus
• Menu storage and rendering logic

Attack Scenario

• An attacker creates or controls a post containing a malicious JavaScript payload.
• The attacker adds the post to the menu using the Posts functionality in Menu Manager.
• The application stores the menu entry without sanitization or encoding.
• The payload persists and executes whenever the menu is rendered.

Impact

• Persistent Stored DOM XSS
• Execution of arbitrary JavaScript in victims’ browsers
• Privilege escalation in administrative contexts
• Full administrator account takeover
• Full account takeover across all roles
• Full compromise of the entire application via global navigation execution

Endpoint:
- /backend/menu/

Steps To Reproduce (POC)

1. Navigate to Menu Management
2. Use the Posts section to add a post containing an XSS payload such as:
   <img src=x onerror=alert(document.domain)>
3. Save the menu
4. View the menu in the administrative panel or any public-facing page
5. Observe the JavaScript payload executing automatically

Remediation

• Avoid unsafe DOM manipulation methods: Do not use .html(), innerHTML, or similar sink functions in client-side JavaScript or server-side templating (e.g., PHP). Even when user input flowing into these sinks is not immediately apparent, they can introduce Cross-Site Scripting (XSS) vulnerabilities that an attacker may exploit.

• Apply output encoding: Implement HTML entity encoding on all user-controlled data before rendering it in the browser. This helps neutralize potentially malicious input.

• Implement input sanitization: Ensure that all user-supplied input is properly sanitized before processing or output. Currently, no sanitization mechanisms are in place, which should be addressed as a priority.

• Enforce security headers and cookie attributes:

• Content Security Policy (CSP): Define and enforce a strict CSP to limit the execution of unauthorized scripts.
• HttpOnly flag: Set the HttpOnly attribute on session cookies to prevent client-side script access.
• SameSite attribute: Configure the SameSite cookie attribute to mitigate Cross-Site Request Forgery (CSRF) risks.
• Secure flag: Ensure all cookies are transmitted only over HTTPS by enabling the Secure attribute.

These measures collectively reduce the impact of XSS and help prevent escalation paths such as CSRF via XSS.

Ready Video POC:

https://mega.nz/file/PcMiUA5K#L2RlZJa340Q8K42TksxiXMuo_9XsRYPi14-WvBnak2A