CVE-2016-2086 in Xcode
Summary
by MITRE
Node.js 0.10.x before 0.10.42, 0.12.x before 0.12.10, 4.x before 4.3.0, and 5.x before 5.6.0 allow remote attackers to conduct HTTP request smuggling attacks via a crafted Content-Length HTTP header.
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Analysis
by VulDB Data Team • 05/19/2019
The vulnerability identified as CVE-2016-2086 represents a critical HTTP request smuggling flaw affecting multiple versions of Node.js runtime environment. This vulnerability specifically targets the handling of Content-Length HTTP headers in the Node.js HTTP server implementation, creating opportunities for attackers to manipulate HTTP request processing. The affected versions include Node.js 0.10.x prior to 0.10.42, 0.12.x prior to 0.12.10, 4.x prior to 4.3.0, and 5.x prior to 5.6.0, indicating a widespread impact across several major release lines. The vulnerability stems from improper validation and processing of HTTP headers, particularly when multiple Content-Length headers are present or when header values are malformed.
The technical flaw manifests when Node.js servers process HTTP requests containing crafted Content-Length headers that can confuse the underlying HTTP parser and lead to request smuggling attacks. This occurs because the Node.js HTTP implementation does not properly validate or normalize Content-Length header values, allowing attackers to inject malicious headers that can cause the server to interpret request boundaries incorrectly. When multiple Content-Length headers are present, the server may use an unexpected value, or when the header value is malformed, it can result in inconsistent request parsing behavior. The vulnerability specifically exploits the HTTP protocol's handling of request bodies and the way servers determine where request data ends, creating opportunities for attackers to inject additional requests or manipulate existing request content. This flaw operates at the application layer and can be exploited through standard HTTP traffic without requiring special privileges or authentication.
The operational impact of CVE-2016-2086 is significant as it enables remote attackers to conduct HTTP request smuggling attacks that can lead to various security consequences including data leakage, authentication bypass, and cross-site request forgery exploitation. Attackers can leverage this vulnerability to manipulate how HTTP requests are processed by intermediate proxies or load balancers, potentially allowing them to access restricted resources or perform unauthorized actions. The vulnerability can be particularly dangerous in environments where Node.js applications are deployed behind HTTP proxies or load balancers, as the request smuggling can be used to bypass security controls and access internal systems. Additionally, the vulnerability can be exploited to perform cache poisoning attacks, where attackers manipulate cached responses or to conduct session hijacking by manipulating request boundaries. The impact extends beyond simple data access as it can undermine the integrity of HTTP communications and potentially compromise entire application stacks that rely on proper HTTP request handling.
Organizations affected by this vulnerability should immediately upgrade to patched versions of Node.js, specifically versions 0.10.42, 0.12.10, 4.3.0, and 5.6.0 respectively. The fix implemented by the Node.js team addresses the HTTP header parsing logic to properly validate Content-Length values and prevent malformed headers from causing request smuggling opportunities. Network administrators should also implement additional monitoring and detection measures to identify potential exploitation attempts, particularly looking for unusual Content-Length header patterns or HTTP request anomalies. Security teams should conduct comprehensive vulnerability assessments of all Node.js applications and review proxy configurations to ensure that intermediate systems are not inadvertently amplifying the impact of this vulnerability. The vulnerability aligns with CWE-444 and CWE-1290 categories related to improper input validation and HTTP request smuggling respectively, and maps to ATT&CK technique T1071.004 for application layer protocol manipulation. Organizations should also consider implementing web application firewalls and HTTP traffic inspection tools to detect and block malicious header patterns that could exploit this vulnerability. Regular security assessments and patch management processes should be enhanced to ensure timely remediation of similar vulnerabilities in the Node.js ecosystem and other web application frameworks.