GHSA-85m8-g393-jcxf CI4MS: Backup Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM Blind XSS

• Packagist ci4-cms-erp/ci4ms: < 0.31.0.0 → fixed in 0.31.0.0

Summary Vulnerability: Stored DOM Blind XSS via Backup Management Filename (Persistent Payload Injection) • Stored Cross-Site Scripting (Blind XSS) via Unsanitized Backup Filename in Backup Management Description The application fails to properly sanitize user-controlled input when handling backup uploads and processing backup metadata. An attacker can inject a malicious JavaScript payload into the backup filename via the uploaded `xss.sql`, which uses SQL functionality to insert the XSS payload server-side. This stored payload is later rendered unsafely in multiple backup management views without proper output encoding, leading to stored blind cross-site scripting (Blind XSS). Affected Functionality • Backup upload functionality • Backup processing functionality • Backup storage and retrieval logic Attack Scenario • An attacker uploads `xss.sql` which uses SQL functionality to insert a malicious XSS payload into the backup filename field server-side. • The application stores this filename without sanitization or encoding. • The payload persists and executes whenever the backup filename is rendered in affected views. • The attacker does not see immediate execution, making this a Blind XSS scenario that triggers only when an administrator or privileged user views the backup management panel. Impact • Persistent Stored Blind XSS • Execution of arbitrary JavaScript in victims’ browsers • Privilege escalation when viewed by administrators or privileged users • Full administrator account takeover • Full account takeover across all roles • Full compromise of the entire application Endpoints: • `/backend/backup/upload` • `/backend/backup/` • `/backup/{id}` Steps To Reproduce (POC) 1. Upload `xss.sql` via the Backup Upload functionality 2. Ensure the SQL executes and inserts an XSS payload into the backup filename field such as: `` 3. Navigate to the Backup Management panel as an administrator 4. View the backup entry via the administrative panel 5. Notice the XSS payload executing automatically (Blind XSS) 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/eNFXgAAA#IETbPcKwr5vVLqJIAdc3uy4qgcVTgyPb_2HhB4zcwAE