CVE-2024-56524: Radware Cloud WAF Auth Bypass Vulnerability

CVE-2024-56524 Overview

CVE-2024-56524 is a critical vulnerability affecting Radware Cloud Web Application Firewall (WAF) that allows remote attackers to bypass firewall filters by adding a special character to HTTP requests. This security flaw enables threat actors to circumvent the WAF's protective mechanisms, potentially allowing malicious payloads to reach protected backend applications undetected. The vulnerability is classified as CWE-116 (Improper Encoding or Escaping of Output), indicating a fundamental failure in how the WAF processes and validates input data.

Critical Impact

Remote attackers can bypass WAF security controls without authentication, potentially exposing protected web applications to SQL injection, XSS, and other web-based attacks that the WAF was designed to block.

Affected Products

• Radware Cloud WAF (versions before 2025-05-07)
• Radware Cloud Security Solutions utilizing Cloud WAF
• Organizations relying on Radware Cloud WAF for web application protection

Discovery Timeline

• 2025-05-12 - CVE-2024-56524 published to NVD
• 2025-07-01 - Last updated in NVD database

Technical Details for CVE-2024-56524

Vulnerability Analysis

This vulnerability represents a significant security bypass in Radware's Cloud WAF solution. The flaw allows attackers to evade detection by inserting special characters into their malicious requests. When the WAF processes these crafted requests, it fails to properly normalize or decode the input before applying its security rules, effectively allowing the malicious payload to pass through unfiltered.

The attack requires no authentication or user interaction, making it trivially exploitable from any network location. Once bypassed, the WAF provides no protection against subsequent attack payloads, leaving backend applications fully exposed to whatever vulnerabilities they may contain. The impact is particularly severe as WAFs are often the primary line of defense for web applications, and organizations may have delayed patching application-level vulnerabilities under the assumption that the WAF would provide adequate protection.

Root Cause

The root cause lies in improper encoding or escaping of output (CWE-116) within the Radware Cloud WAF's request processing pipeline. The WAF fails to properly normalize special characters before applying its security filter rules. This normalization gap creates a mismatch between how the WAF interprets the request and how the backend application ultimately processes it, allowing attackers to craft payloads that appear benign to the WAF but execute maliciously on the target application.

Attack Vector

The attack is conducted over the network and requires no privileges or user interaction. An attacker simply needs to append or inject specific special characters into their HTTP requests to evade WAF detection. This technique is commonly known as WAF bypass through encoding manipulation or filter evasion.

The attack flow typically involves:

1. Attacker identifies a target protected by Radware Cloud WAF
2. Attacker crafts a malicious request (e.g., SQL injection, XSS payload)
3. Attacker modifies the payload by adding special characters that cause the WAF to misinterpret the request
4. The modified request passes through the WAF undetected
5. The backend application processes the malicious payload, leading to exploitation

For detailed technical information about this vulnerability, refer to the CERT Vulnerability Advisory 722229.

Detection Methods for CVE-2024-56524

Indicators of Compromise

• Unusual HTTP requests containing unexpected special characters or encoding sequences in attack payloads
• Backend application logs showing successful exploitation attempts (SQL injection errors, XSS reflections) that should have been blocked by the WAF
• Discrepancies between WAF-reported blocked attacks and actual attack traffic reaching applications
• Evidence of data exfiltration or unauthorized access originating from requests that passed through the WAF

Detection Strategies

• Implement application-level logging independent of WAF reporting to identify attacks that bypass WAF controls
• Deploy SentinelOne Singularity XDR to monitor backend application behavior for exploitation indicators regardless of WAF status
• Compare WAF access logs against application access logs to identify filtering gaps
• Monitor for known WAF bypass patterns including special character injection techniques

Monitoring Recommendations

• Enable verbose logging on backend web applications to capture all incoming requests for forensic analysis
• Implement anomaly detection for requests containing unusual character combinations or encoding patterns
• Set up alerts for any successful exploitation attempts on backend applications that should be protected by WAF rules
• Regularly audit WAF effectiveness by testing filter bypass scenarios in a controlled environment

How to Mitigate CVE-2024-56524

Immediate Actions Required

• Verify your Radware Cloud WAF instance has been updated to the patched version released on or after 2025-05-07
• Contact Radware support to confirm patch status if uncertain about your current deployment version
• Implement additional application-level input validation as a defense-in-depth measure
• Review application logs for evidence of bypass exploitation during the vulnerable period

Patch Information

Radware has addressed this vulnerability in their Cloud WAF service as of 2025-05-07. As this is a cloud-based service, the patch should be automatically applied to customer deployments. Organizations should verify with Radware that their specific instance has received the security update. For more information about Radware's cloud security solutions and updates, visit the Radware Cloud Security Solutions page.

Workarounds

• Deploy additional security layers such as SentinelOne Singularity for endpoint and workload protection to detect exploitation attempts that bypass the WAF
• Implement strict input validation at the application level to block malicious payloads regardless of WAF status
• Consider deploying a secondary WAF solution from a different vendor as a temporary measure until the patch is confirmed
• Enable enhanced logging and monitoring to detect any exploitation attempts while awaiting patch verification

# Verify WAF configuration and enable enhanced logging
# Contact Radware support to confirm patch deployment status
# Review application-level security controls as defense-in-depth

# Example: Enable additional application logging for bypass detection
# Configure your web server to log all request parameters
# Apache example:
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" \"%{X-Forwarded-For}i\"" combined_plus
CustomLog logs/access_log combined_plus

# Nginx example:
log_format detailed '$remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent" '
                    '"$request_body"';