CVE-2007-1608 in WebSphere Application Server
Summary
by MITRE
CRLF injection vulnerability in IBM WebSphere Application Server (WAS) before 6.0.2.19 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a single CRLF sequence in a context that is not a valid multi-line header.
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Analysis
by VulDB Data Team • 06/09/2025
The vulnerability identified as CVE-2007-1608 represents a critical CRLF injection flaw in IBM WebSphere Application Server versions prior to 6.0.2.19. This vulnerability falls under the CWE-113 category of Improper Neutralization of CRLF Sequences in HTTP Headers, which is a well-documented weakness in web application security. The flaw specifically manifests when the application server fails to properly sanitize user input containing carriage return line feed sequences, allowing malicious actors to inject arbitrary HTTP headers into responses. The vulnerability is particularly dangerous because it occurs in contexts where CRLF sequences are not expected to be valid multi-line headers, creating a pathway for attackers to manipulate HTTP responses at the application level.
The technical exploitation of this vulnerability enables attackers to perform HTTP response splitting attacks by injecting single CRLF sequences into input fields that are then processed by the WebSphere server. When the server processes user-supplied data containing these sequences, it fails to properly escape or validate the input before incorporating it into HTTP headers. This allows attackers to inject malicious headers that can redirect users to malicious websites, steal session cookies, or manipulate web application behavior. The attack vector typically involves crafting input data that contains CRLF characters followed by malicious HTTP headers, which are then inserted into the server's response without proper sanitization. This creates a scenario where the server's response can contain multiple distinct HTTP responses, enabling sophisticated attacks such as cross-site scripting or session hijacking.
The operational impact of this vulnerability is significant for organizations running affected IBM WebSphere Application Server versions, as it provides attackers with a direct method to compromise web application security. Response splitting attacks can lead to various security breaches including session fixation, cross-site scripting, and cache poisoning attacks. The vulnerability affects the integrity of HTTP communications between clients and servers, potentially allowing attackers to manipulate the entire HTTP response flow. Organizations using older WebSphere versions are particularly at risk since the vulnerability has been present for years and affects core web application functionality. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous for publicly accessible web applications.
Mitigation strategies for CVE-2007-1608 primarily focus on upgrading to IBM WebSphere Application Server 6.0.2.19 or later versions where the vulnerability has been addressed through proper input validation and sanitization. Organizations should implement comprehensive input validation at all entry points where user data is processed, ensuring that CRLF sequences are properly escaped or removed from HTTP headers. The implementation of web application firewalls and security monitoring tools can help detect and prevent exploitation attempts by monitoring for suspicious CRLF sequences in HTTP headers. Additionally, organizations should conduct regular security assessments and penetration testing to identify potential injection points within their web applications. The remediation process should include thorough code reviews focusing on HTTP header generation and input handling routines, as well as implementing proper encoding mechanisms for user-supplied data before it is incorporated into HTTP responses. Organizations should also consider implementing strict header validation policies and monitoring for unusual HTTP response patterns that might indicate exploitation attempts.