CVE-2021-23228
📋 TL;DR
DIAEnergie versions 1.7.5 and earlier contain a reflected cross-site scripting (XSS) vulnerability in error pages that process .NET Request.QueryString input without proper sanitization. This allows attackers to inject malicious scripts that execute in victims' browsers when they visit crafted URLs. Organizations using DIAEnergie for industrial control system energy management are affected.
💻 Affected Systems
- DIAEnergie
📦 What is this software?
Diaenergie by Deltaww
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, redirect users to malicious sites, perform actions on behalf of authenticated users, or deliver malware through the compromised application.
Likely Case
Attackers craft phishing emails with malicious links that execute scripts in victims' browsers, potentially stealing credentials or session tokens from authenticated DIAEnergie users.
If Mitigated
With proper input validation and output encoding, malicious scripts are neutralized before reaching user browsers, preventing successful exploitation.
🎯 Exploit Status
Reflected XSS vulnerabilities typically require user interaction (clicking a malicious link) but are straightforward to exploit once the vulnerable parameter is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 1.7.6 or later
Vendor Advisory: https://www.cisa.gov/uscert/ics/advisories/icsa-21-238-03
Restart Required: Yes
Instructions:
1. Download DIAEnergie version 1.7.6 or later from the vendor. 2. Backup current installation and data. 3. Install the updated version following vendor documentation. 4. Restart the DIAEnergie service and verify functionality.
🔧 Temporary Workarounds
Input Validation Filter
windowsImplement server-side input validation to sanitize QueryString parameters before processing.
Implement ASP.NET input validation filters in web.config or code-behind to strip/escape script tags and special characters from QueryString parameters.
Web Application Firewall (WAF)
allDeploy a WAF with XSS protection rules to block malicious requests containing script payloads.
Configure WAF rules to detect and block requests containing <script>, javascript:, and other XSS payload patterns in QueryString parameters.
🧯 If You Can't Patch
- Implement Content Security Policy (CSP) headers to restrict script execution sources and prevent inline script execution.
- Deploy the application behind a reverse proxy that sanitizes QueryString parameters and adds output encoding.
🔍 How to Verify
Check if Vulnerable:
Test by accessing error pages with crafted QueryString parameters containing script payloads (e.g., ?error=<script>alert('XSS')</script>) and check if scripts execute in browser.Check Version:
Check DIAEnergie version through the application interface or by examining installed program version in Windows Control Panel.Verify Fix Applied:
After patching, repeat the vulnerability test with script payloads; scripts should not execute and should be displayed as plain text or blocked entirely.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to error pages containing script tags, javascript:, or other XSS payload patterns in QueryString parameters.
- Unusual error page access patterns from external IP addresses.
Network Indicators:
- HTTP requests with suspicious QueryString parameters containing script payloads sent to DIAEnergie servers.
SIEM Query:
source="web_server_logs" AND uri="*error*" AND query_string="*<script>*" OR query_string="*javascript:*"