CVE-2024-56524 Overview
CVE-2024-56524 is a filter bypass vulnerability in Radware Cloud Web Application Firewall (WAF) affecting versions released before 2025-05-07. Remote attackers can bypass firewall filtering rules by appending a special character to HTTP requests. The flaw stems from improper output encoding or escaping [CWE-116], allowing malicious traffic to reach protected origin applications. Because the WAF is positioned as a primary perimeter control, a bypass exposes downstream web applications to attacks the WAF was deployed to block, including injection and exploitation attempts against application logic.
Critical Impact
Unauthenticated remote attackers can bypass WAF protection by manipulating request syntax, exposing backend applications to attacks the WAF should filter.
Affected Products
- Radware Cloud WAF versions before 2025-05-07
- Web applications protected exclusively by Radware Cloud WAF
- Origin servers relying on Radware Cloud WAF for input filtering
Discovery Timeline
- 2025-05-12 - CVE-2024-56524 published to the National Vulnerability Database (NVD)
- 2025-07-01 - Last updated in NVD database
Technical Details for CVE-2024-56524
Vulnerability Analysis
The vulnerability is classified under [CWE-116] Improper Encoding or Escaping of Output. Radware Cloud WAF inspects incoming HTTP requests against signature and rule-based filters intended to block malicious payloads. By inserting a specific special character into a request, an attacker can alter how the WAF parses request content. The filter engine fails to normalize or correctly interpret the modified request before applying detection rules. As a result, malicious payloads pass through the WAF unblocked while still being processed normally by the protected backend application.
Root Cause
The root cause is a parser discrepancy between the WAF and origin server. The WAF treats a request containing the special character as benign or malformed, skipping rule application, while the origin web server interprets the same request as valid and processes the embedded payload. This dual-parser inconsistency is a recurring class of WAF bypass and is documented in CERT Vulnerability Report #722229.
Attack Vector
Exploitation occurs over the network without authentication or user interaction. An attacker crafts a standard HTTP or HTTPS request, embedding the special character in a position that affects WAF parsing. The request is sent to any web application protected by Radware Cloud WAF. The bypass enables delivery of payloads such as SQL injection, cross-site scripting, or command injection that the WAF would otherwise block.
No verified public exploit code is available. Refer to Radware Cloud Security Solutions and the CERT Vulnerability Report #722229 for additional technical context.
Detection Methods for CVE-2024-56524
Indicators of Compromise
- HTTP requests containing unusual special characters in URI paths, query parameters, headers, or body fields that do not match application schemas
- WAF logs showing requests passed as clean while backend application logs record injection-style payloads for the same request ID
- Unexpected backend application errors or successful attack signatures appearing in origin server logs without corresponding WAF alerts
Detection Strategies
- Correlate Radware Cloud WAF access logs with origin server logs to find requests that bypass WAF rules but trigger anomalies downstream
- Deploy backend intrusion detection rules at the origin server to identify injection payloads regardless of WAF verdict
- Hunt for requests with unusual byte sequences, encoded characters, or malformed request lines that historically did not appear in baseline traffic
Monitoring Recommendations
- Forward WAF and origin server logs into a centralized analytics platform for cross-source correlation
- Alert on discrepancies where the WAF returns allow verdicts but the origin returns server-side errors associated with attack payloads
- Monitor for sudden changes in request structure or character distribution across endpoints protected by the WAF
How to Mitigate CVE-2024-56524
Immediate Actions Required
- Confirm with Radware that your Cloud WAF tenant is running the post 2025-05-07 release that addresses the bypass
- Review WAF logs for the past 90 days for requests containing anomalous special characters targeting sensitive endpoints
- Enable defense-in-depth controls at origin servers so application-layer filtering does not rely solely on the WAF
Patch Information
Radware addressed the vulnerability in Cloud WAF releases dated on or after 2025-05-07. Because Radware Cloud WAF is a managed service, the fix is applied by the vendor across tenants. Customers should validate the active service version through the Radware management console and contact Radware support to confirm remediation status. See Radware Cloud Security Solutions for service documentation.
Workarounds
- Deploy a secondary input validation layer at the application or reverse proxy tier that strips or normalizes uncommon special characters
- Implement strict allow-list input validation in backend applications for parameters with predictable formats
- Apply rate limiting and anomaly-based blocking at origin servers to constrain exploitation attempts even when WAF filtering is evaded
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
