CVE-2011-1475 in Tomcat
Summary
by MITRE
The HTTP BIO connector in Apache Tomcat 7.0.x before 7.0.12 does not properly handle HTTP pipelining, which allows remote attackers to read responses intended for other clients in opportunistic circumstances by examining the application data in HTTP packets, related to "a mix-up of responses for requests from different users."
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability described in CVE-2011-1475 represents a critical flaw in Apache Tomcat's HTTP BIO connector implementation that stems from improper handling of HTTP pipelining mechanisms. This issue affects versions 7.0.x prior to 7.0.12 and creates a scenario where response data intended for one client can be inadvertently exposed to another client within the same connection session. The vulnerability operates through a fundamental mismanagement of HTTP request-response cycles where the connector fails to properly isolate and route responses to their respective requesting clients.
The technical root cause of this vulnerability lies in the connector's inability to maintain proper separation between concurrent HTTP requests within a single connection. When multiple requests are sent in a pipeline sequence, the HTTP BIO connector does not adequately track which response corresponds to which specific request, leading to a situation where response data can be mixed up or improperly delivered. This misconfiguration creates a data leakage condition where malicious actors can potentially intercept and analyze application data from HTTP packets, effectively allowing them to access information that should be private to other users. The vulnerability specifically targets the HTTP pipelining feature which allows multiple requests to be sent over a single connection without waiting for individual responses, a common optimization technique in web server implementations.
From an operational perspective, this vulnerability poses significant security risks to applications running on affected Tomcat versions. Attackers can exploit this weakness to perform cross-client data leakage attacks, potentially accessing sensitive information such as session data, user credentials, or application-specific responses intended for other authenticated users. The opportunistic nature of this vulnerability means that exploitation can occur without requiring extensive prior knowledge or sophisticated attack vectors, making it particularly dangerous in production environments where multiple users share connections. The impact extends beyond simple information disclosure to potentially enable session hijacking or other advanced persistent threats that leverage the leaked response data for further exploitation.
The vulnerability maps directly to CWE-200, which addresses improper information exposure, and aligns with several ATT&CK techniques including T1041, which covers data from network shared modules, and T1566, focusing on credential access through network attacks. Organizations running affected Tomcat versions should prioritize immediate patching to address this issue, as the vulnerability can be exploited remotely without authentication requirements. Mitigation strategies should include upgrading to Tomcat 7.0.12 or later versions where the HTTP BIO connector properly handles pipelining scenarios, implementing additional network-level monitoring to detect anomalous response patterns, and considering connection-level restrictions that limit or disable HTTP pipelining where possible. Security teams should also conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and ensure that all Tomcat deployments are updated to versions that properly address this response mixing vulnerability.