CVE-2023-30455
📋 TL;DR
This vulnerability allows attackers to cause a Denial-of-Service condition in ebankIT banking platforms by sending specially crafted requests with excessive e-statement IDs. The server becomes unresponsive for approximately 60 seconds per attack, enabling sustained disruption. All ebankIT users running vulnerable versions are affected.
💻 Affected Systems
- ebankIT
📦 What is this software?
Ebankit by Ebankit
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability for all users through sustained DoS attacks, potentially disrupting banking operations and causing financial impact.
Likely Case
Intermittent service degradation and slow response times affecting user experience and banking operations.
If Mitigated
Minimal impact with proper rate limiting and input validation in place.
🎯 Exploit Status
Exploitation requires only basic HTTP knowledge and can be automated with simple scripts.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 7 or later
Vendor Advisory: https://blog.ebankit.com/blog-press
Restart Required: Yes
Instructions:
1. Upgrade ebankIT to version 7 or later. 2. Restart the ebankIT application services. 3. Verify the fix by testing the vulnerable endpoint.
🔧 Temporary Workarounds
Rate Limiting Implementation
windowsImplement rate limiting on the /Controls/Generic/EBMK/Handlers/EStatements/DownloadEStatement.ashx endpoint
Configure web server (IIS/Apache) rate limiting rules for the specific endpoint
WAF Rule Configuration
allAdd Web Application Firewall rules to block requests with excessive EStatementsIds parameter values
Configure WAF to reject requests with >10 comma-separated values in EStatementsIds parameter
🧯 If You Can't Patch
- Implement strict input validation to limit the number of EStatementsIds to a reasonable maximum (e.g., 10)
- Deploy network-level rate limiting and DDoS protection for the vulnerable endpoint
🔍 How to Verify
Check if Vulnerable:
Send a GET request to /Controls/Generic/EBMK/Handlers/EStatements/DownloadEStatement.ashx with EStatementsIds parameter containing 100+ comma-separated values and measure response time.Check Version:
Check ebankIT administration panel or application configuration files for version information.Verify Fix Applied:
After patching, repeat the vulnerable request - server should reject or quickly process the request without 60-second delay.📡 Detection & Monitoring
Log Indicators:
- Multiple requests to DownloadEStatement.ashx with large EStatementsIds values
- Extended processing times (60+ seconds) for the endpoint
- Increased error rates or timeouts following suspicious requests
Network Indicators:
- High volume of requests to the specific endpoint from single IPs
- Pattern of requests with 100+ comma-separated values in parameter
SIEM Query:
source="web_server" AND uri="/Controls/Generic/EBMK/Handlers/EStatements/DownloadEStatement.ashx" AND parameter="EStatementsIds" AND value_count>10