CVE-2014-0227 in Communications Policy Management
Summary
by MITRE
java/org/apache/coyote/http11/filters/ChunkedInputFilter.java in Apache Tomcat 6.x before 6.0.42, 7.x before 7.0.55, and 8.x before 8.0.9 does not properly handle attempts to continue reading data after an error has occurred, which allows remote attackers to conduct HTTP request smuggling attacks or cause a denial of service (resource consumption) by streaming data with malformed chunked transfer coding.
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Analysis
by VulDB Data Team • 09/27/2022
The vulnerability identified as CVE-2014-0227 represents a critical flaw in Apache Tomcat's handling of HTTP chunked transfer encoding, specifically within the ChunkedInputFilter component. This issue affects multiple versions of the popular web application server, including Apache Tomcat 6.x versions prior to 6.0.42, 7.x versions prior to 7.0.55, and 8.x versions prior to 8.0.9. The vulnerability stems from improper error handling mechanisms that fail to correctly terminate data streams when malformed chunked transfer coding is detected, creating exploitable conditions for attackers to manipulate HTTP request processing.
The technical implementation of this vulnerability resides in the ChunkedInputFilter.java file where the application processes incoming HTTP requests using chunked transfer encoding. When an error occurs during chunked data processing, the filter does not properly terminate the input stream, allowing attackers to continue streaming malformed data. This behavior creates a state where the HTTP parser becomes confused about the request boundaries and can be manipulated to process requests in unintended ways. The flaw specifically manifests when the system attempts to read additional data after an error condition has already been detected, leading to inconsistent parsing behavior that can be exploited for various attack vectors.
From an operational perspective, this vulnerability enables two primary attack vectors that pose significant risks to affected systems. Remote attackers can leverage this weakness to conduct HTTP request smuggling attacks, where they manipulate the HTTP protocol to bypass security controls and potentially gain unauthorized access to protected resources. Additionally, the vulnerability allows for denial of service conditions through resource consumption attacks, where malicious actors can exhaust system resources by sending carefully crafted malformed chunked data streams that cause the server to consume excessive memory or processing power. The impact extends beyond simple service disruption as the request smuggling capability can be used to bypass security mechanisms and access restricted content.
The vulnerability aligns with CWE-129, which addresses improper handling of input boundaries, and represents a classic example of how inadequate error handling can create security weaknesses in network protocols. From an ATT&CK framework perspective, this vulnerability maps to techniques involving protocol manipulation and resource exhaustion, with potential for privilege escalation through request smuggling attacks. The attack surface is particularly concerning given Apache Tomcat's widespread deployment across enterprise environments, making this vulnerability a high-priority target for threat actors seeking to compromise web applications.
Organizations affected by this vulnerability should implement immediate mitigations including updating to the patched versions of Apache Tomcat where the issue has been resolved through proper error handling mechanisms in the chunked input filter. Additional defensive measures include implementing network-level controls such as web application firewalls that can detect and block malformed chunked transfer encoding patterns, configuring proper input validation at the application level, and monitoring for unusual resource consumption patterns that may indicate exploitation attempts. System administrators should also consider implementing rate limiting and connection timeouts to limit the impact of potential denial of service attacks while ensuring that the application remains responsive to legitimate users.