CVE-2017-1503 in WebSphere Application Server
Summary
by MITRE
IBM WebSphere Application Server 7.0, 8.0, 8.5, and 9.0 is vulnerable to HTTP response splitting attacks. A remote attacker could exploit this vulnerability using specially-crafted URL to cause the server to return a split response, once the URL is clicked. This would allow the attacker to perform further attacks, such as Web cache poisoning, cross-site scripting, and possibly obtain sensitive information. IBM X-Force ID: 129578.
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Analysis
by VulDB Data Team • 01/16/2021
IBM WebSphere Application Server versions 7.0, 8.0, 8.5, and 9.0 contain a critical HTTP response splitting vulnerability that stems from inadequate input validation in URL handling mechanisms. This vulnerability manifests when the application server processes specially crafted URLs that contain maliciously formatted characters or sequences designed to manipulate the HTTP response headers. The flaw exists in the server's HTTP response construction logic where it fails to properly sanitize or encode user-supplied input before incorporating it into response headers or body content. The vulnerability is classified as a CWE-113 vulnerability, specifically related to improper neutralization of CRLF characters in HTTP headers, which directly enables the response splitting attack vector. Attackers can exploit this weakness by crafting URLs that contain carriage return and line feed characters within the URL parameters or path components, causing the server to generate multiple HTTP responses instead of a single intended response.
The operational impact of this vulnerability extends beyond simple response manipulation and creates a comprehensive attack surface for malicious actors. When successfully exploited, the vulnerability enables attackers to inject malicious content into the HTTP response stream, potentially allowing for Web cache poisoning attacks where cached responses can be manipulated to serve malicious content to multiple users. The vulnerability also facilitates cross-site scripting attacks by enabling attackers to inject script code into response headers or body content, which can then be executed in the victim's browser context. Additionally, the vulnerability may allow for sensitive information disclosure, as attackers can potentially manipulate response headers to redirect or alter the content being returned to clients. The attack can be executed remotely without requiring authentication, making it particularly dangerous in environments where the application server is exposed to untrusted networks.
The exploitation of this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly under the T1190 - Proxy Execution and T1059 - Command and Scripting Interpreter tactics. The vulnerability enables attackers to perform HTTP response splitting attacks that can be used as a precursor to more sophisticated attacks such as session hijacking or man-in-the-middle attacks. Organizations running affected WebSphere versions should prioritize immediate remediation through official IBM security patches, as the vulnerability affects multiple major releases and has been actively exploited in the wild. The recommended mitigation strategies include implementing proper input validation and sanitization at all entry points, configuring the application server to reject or encode potentially dangerous characters in URL parameters, and deploying web application firewalls that can detect and block malicious URL patterns. Network segmentation and monitoring should also be enhanced to detect suspicious traffic patterns that may indicate exploitation attempts, as the vulnerability can be leveraged to establish persistent attack vectors within the network infrastructure.