CVE-2024-51451 Overview
IBM Concert versions 1.0.0 through 2.1.0 contain an HTTP header injection vulnerability caused by improper validation of input by the HOST headers. This security flaw allows attackers to conduct various attacks against vulnerable systems, including cross-site scripting (XSS), cache poisoning, and session hijacking.
Critical Impact
Attackers can exploit improper HOST header validation to inject malicious content, potentially compromising user sessions and manipulating cached responses across the affected IBM Concert deployment.
Affected Products
- IBM Concert 1.0.0
- IBM Concert 1.0.1 through 2.0.x
- IBM Concert 2.1.0
Discovery Timeline
- 2026-02-04 - CVE-2024-51451 published to NVD
- 2026-02-05 - Last updated in NVD database
Technical Details for CVE-2024-51451
Vulnerability Analysis
This vulnerability falls under CWE-644 (Improper Neutralization of HTTP Headers for Scripting Syntax), which occurs when an application does not properly neutralize or validate HTTP headers before they are used in scripted contexts. The vulnerability enables network-based attacks without requiring authentication or user interaction.
The flaw resides in IBM Concert's handling of HOST headers, where insufficient input validation allows attackers to inject arbitrary HTTP headers into responses. This can lead to multiple attack scenarios including XSS execution in victim browsers, web cache poisoning that affects all users of shared caches, and session hijacking through manipulated responses.
Root Cause
The root cause is improper validation of the HTTP HOST header input. When IBM Concert processes incoming HTTP requests, it fails to adequately sanitize or validate the HOST header values before incorporating them into server responses or internal processing logic. This lack of input validation allows specially crafted header values to be injected and interpreted in unintended ways.
Attack Vector
The attack vector is network-based, meaning an attacker can exploit this vulnerability remotely over HTTP/HTTPS connections. The attack does not require any privileges or user interaction, making it particularly accessible to opportunistic attackers.
An attacker can craft malicious HTTP requests with specially formatted HOST header values containing injected content such as additional headers, newline characters (CRLF), or script payloads. When the vulnerable IBM Concert instance processes these requests, the injected content may be reflected in responses, stored in caches, or used in ways that compromise security controls.
The vulnerability enables several attack types:
- Cross-Site Scripting (XSS): Injected scripts execute in victim browsers
- Cache Poisoning: Malicious responses are cached and served to other users
- Session Hijacking: Manipulated headers interfere with session management
Detection Methods for CVE-2024-51451
Indicators of Compromise
- Unusual or malformed HOST header values in web server access logs containing CRLF sequences (%0d%0a or \r\n)
- HTTP responses containing unexpected headers or duplicate headers
- Evidence of cache poisoning with responses that differ from legitimate application behavior
- XSS payload signatures in HOST header fields within request logs
Detection Strategies
- Implement web application firewall (WAF) rules to detect and block HTTP header injection attempts in HOST headers
- Configure log monitoring to alert on requests containing CRLF sequences or other injection patterns in header fields
- Deploy network intrusion detection signatures for HTTP header manipulation attacks
- Review IBM Concert access logs for anomalous HOST header patterns that don't match expected domain names
Monitoring Recommendations
- Enable detailed HTTP request logging on IBM Concert instances to capture full header content
- Monitor for increased cache miss rates or cache inconsistencies that may indicate poisoning attempts
- Set up alerts for XSS detection signatures in downstream security tools
- Track session anomalies that could indicate hijacking attempts following header injection
How to Mitigate CVE-2024-51451
Immediate Actions Required
- Upgrade IBM Concert to a patched version as specified in the vendor security advisory
- Implement WAF rules to filter malicious HOST header values pending patch deployment
- Review and restrict access to IBM Concert instances to trusted networks where possible
- Enable enhanced logging to detect exploitation attempts
Patch Information
IBM has released a security update to address this vulnerability. Detailed patch information and installation instructions are available in the IBM Support Page. Organizations running IBM Concert versions 1.0.0 through 2.1.0 should apply the security update immediately.
Workarounds
- Deploy a reverse proxy or WAF in front of IBM Concert to validate and sanitize HOST header values before they reach the application
- Configure web servers to reject requests with malformed or unexpected HOST headers
- Implement strict HOST header whitelisting at the network edge to only allow legitimate domain names
- If feasible, restrict network access to IBM Concert instances to trusted internal networks until patching is complete
# Example WAF rule concept for HOST header validation (implementation varies by WAF vendor)
# Block requests with CRLF injection attempts in HOST header
# Pattern: HOST header containing %0d, %0a, \r, or \n characters
SecRule REQUEST_HEADERS:Host "@rx (%0d|%0a|\\r|\\n)" "id:100001,phase:1,deny,status:403,msg:'HTTP Header Injection Attempt'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
