CVE-2012-3544 in Sun Ray Software
Summary
by MITRE
Apache Tomcat 6.x before 6.0.37 and 7.x before 7.0.30 does not properly handle chunk extensions in chunked transfer coding, which allows remote attackers to cause a denial of service by streaming data.
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Analysis
by VulDB Data Team • 02/09/2022
The vulnerability identified as CVE-2012-3544 represents a critical flaw in Apache Tomcat's handling of HTTP chunked transfer encoding mechanisms. This issue affects versions prior to 6.0.37 and 7.0.30, creating a significant security risk that can be exploited by remote attackers to disrupt service availability. The flaw specifically manifests in how Tomcat processes chunk extensions within chunked transfer coding, a standard HTTP mechanism used to transfer data in multiple chunks when the total size is unknown or when streaming data. When an attacker crafts malicious HTTP requests with malformed chunk extensions, the server's processing logic becomes vulnerable to exploitation.
The technical implementation of this vulnerability stems from inadequate input validation and parsing of chunked transfer coding headers. In HTTP protocols, chunked transfer encoding allows data to be sent in a series of chunks, each with its own size indicator. The system properly handles the chunk size but fails to correctly validate or sanitize additional chunk extensions that may be included in the chunk header. This oversight creates a potential for resource exhaustion or processing errors that can be amplified through carefully crafted malicious requests. Attackers can exploit this by sending HTTP requests that contain specially formatted chunk extensions designed to trigger memory allocation issues or infinite loop conditions within the Tomcat server's HTTP parser.
The operational impact of CVE-2012-3544 manifests as a reliable denial of service condition that can affect any web application hosted on vulnerable Tomcat instances. When exploited, the vulnerability allows remote attackers to consume excessive system resources such as memory and CPU cycles, leading to service unavailability for legitimate users. The attack vector is particularly dangerous because it requires minimal privileges and can be executed from any network location with access to the target server. The vulnerability aligns with CWE-129, which describes improper validation of length fields, and can be categorized under ATT&CK technique T1499.1 for network denial of service attacks. Organizations running affected versions of Tomcat may experience complete service disruption, potentially resulting in financial losses, reputational damage, and compliance violations.
Mitigation strategies for this vulnerability center on immediate software updates to patched versions of Apache Tomcat. System administrators should prioritize upgrading to Tomcat 6.0.37 or 7.0.30, which contain fixes specifically addressing the chunked transfer encoding parsing issues. Additionally, implementing network-level protections such as firewalls and intrusion detection systems can help detect and block malicious chunked transfer encoding patterns. Organizations should also consider deploying application firewalls that can inspect and filter HTTP traffic for malformed chunked encoding patterns. Regular security assessments and vulnerability scanning should be conducted to ensure no other instances of the vulnerability exist within the infrastructure. The fix implemented in the patched versions involves enhanced validation of chunk extensions and more robust error handling during chunked transfer encoding processing, preventing the exploitation scenarios that led to resource exhaustion and service disruption.