Ekuiper, Stored Cross-Site Scripting (XSS), CVE-2023-XXXX (Critical)

How the CVE Works:

The vulnerability arises in Ekuiper, an edge lightweight IoT data analytics/streaming software, where a user with modification rights (e.g., `kuiperUser` role) can inject a malicious XSS payload into the Rule ID parameter. When another user, such as an admin, interacts with the rule (e.g., updates, runs, stops, or deletes it), the payload executes in the victim’s browser. The issue stems from unsafe notification handling in the code, where data written to `http.ResponseWriter` bypasses HTML escaping, a critical defense mechanism against XSS attacks. Although some protection mechanisms limit the use of special characters, attackers can still craft potent payloads to exploit this vulnerability.

DailyCVE Form:

Platform: Ekuiper
Version: Pre-1.8.0
Vulnerability: Stored XSS
Severity: Critical
Date: 2023-10-XX

What Undercode Say:

Exploitation:

1. Payload Injection:

• Create a rule with a malicious ID: <iframe src="javascript:alert1337">.
• Submit the rule to the Ekuiper server.

2. Triggering the Payload:

• When an admin interacts with the rule (e.g., starts or updates it), the payload executes in their browser.

3. Impact:

• Unauthorized access to sensitive data.
• Session hijacking.
• Malware propagation.

Protection:

1. Input Sanitization:

• Implement strict input validation and sanitization for the Rule ID parameter.
• Example in Go:

  import "html/template"
  func sanitizeInput(input string) string {
  return template.HTMLEscapeString(input)
  }
  

2. Output Encoding:

• Ensure all data written to `http.ResponseWriter` is properly HTML-escaped.
• Example:

  func safeWrite(w http.ResponseWriter, data string) {
  w.Write([]byte(template.HTMLEscapeString(data)))
  }
  

3. Content Security Policy (CSP):

• Enforce a strict CSP to mitigate XSS risks.
• Example CSP header:

  Content-Security-Policy: default-src 'self'; script-src 'self'; object-src 'none';
  

4. Patch Application:

• Update Ekuiper to version 1.8.0 or later, where this vulnerability is patched.

5. Regular Security Audits:

• Conduct periodic code reviews and penetration testing to identify and fix similar vulnerabilities.

Commands for Testing:

• Use tools like Burp Suite or OWASP ZAP to test for XSS vulnerabilities.
• Example curl command to test payload injection:

  curl -X POST -d '{"rule_id": "</li>
  </ul>
  
  <
  
  iframe src=\"javascript:alert(<code>1337</code>)\">"}' http://ekuiper-server/rules
  

  References:

  • bash
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    By following these steps, organizations can mitigate the risks associated with this critical vulnerability and ensure the security of their Ekuiper deployments.

  References:

  Reported By: https://github.com/advisories/GHSA-6hrw-x7pr-4mp8
  Extra Source Hub:
  Undercode

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