CVE-2014-0099 in Communications Policy Management
Summary
by MITRE
Integer overflow in java/org/apache/tomcat/util/buf/Ascii.java in Apache Tomcat before 6.0.40, 7.x before 7.0.53, and 8.x before 8.0.4, when operated behind a reverse proxy, allows remote attackers to conduct HTTP request smuggling attacks via a crafted Content-Length HTTP header.
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Analysis
by VulDB Data Team • 09/27/2022
The vulnerability identified as CVE-2014-0099 represents a critical integer overflow flaw within Apache Tomcat's HTTP request handling mechanism, specifically in the Ascii.java file located at java/org/apache/tomcat/util/buf/Ascii.java. This vulnerability affects multiple versions of the Tomcat web server including versions prior to 6.0.40, 7.x prior to 7.0.53, and 8.x prior to 8.0.4, creating a significant security risk when Tomcat operates behind a reverse proxy configuration. The flaw stems from improper validation of HTTP Content-Length header values, which can be manipulated by remote attackers to exploit the integer overflow condition.
The technical implementation of this vulnerability involves the manipulation of HTTP Content-Length headers during proxy operations, where the integer overflow occurs in the buffer handling routines of Tomcat's HTTP processing pipeline. When a reverse proxy forwards requests to Tomcat, the application processes the Content-Length header value without adequate bounds checking, allowing attackers to craft malicious headers that trigger integer overflow conditions. This overflow can result in the truncation or wrapping of large integer values, effectively bypassing normal content length validation mechanisms and enabling attackers to manipulate the HTTP request parsing process.
The operational impact of this vulnerability extends beyond simple request manipulation, as it enables sophisticated HTTP request smuggling attacks that can be leveraged for various malicious purposes including session hijacking, cross-site scripting attacks, and data exfiltration. Attackers can exploit this vulnerability to inject additional requests into the HTTP processing pipeline, potentially bypassing security controls and gaining unauthorized access to protected resources. The vulnerability is particularly dangerous in environments where Tomcat serves as a backend application server behind reverse proxy configurations, as the proxy-to-backend communication chain creates multiple opportunities for exploitation.
From a cybersecurity perspective, this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions in software implementations, and represents a significant concern within the ATT&CK framework under the technique of "Proxy Execution" and "Command and Scripting Interpreter" categories. The vulnerability demonstrates how seemingly minor buffer handling flaws can be escalated into serious security incidents that compromise the integrity of web application communications. Organizations utilizing Apache Tomcat in production environments must understand that this vulnerability can be exploited to undermine the fundamental security assumptions of HTTP request processing, particularly in complex deployment scenarios involving reverse proxy architectures.
Mitigation strategies for CVE-2014-0099 require immediate patching of affected Tomcat versions to the recommended secure releases, alongside implementation of additional network-level controls such as proxy configuration hardening and Content-Length header validation. Organizations should also consider deploying web application firewalls that can detect and block suspicious Content-Length header patterns, while implementing monitoring solutions that can identify anomalous HTTP request behaviors indicative of exploitation attempts. Regular security assessments and penetration testing should be conducted to verify that the patched environment properly handles HTTP request processing without exposing similar vulnerabilities in custom application code or third-party components that may interact with Tomcat's HTTP handling mechanisms.