CVE-2019-17559 in Traffic Server
Summary
by MITRE
There is a vulnerability in Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5 with a smuggling attack and scheme parsing. Upgrade to versions 7.1.9 and 8.0.6 or later versions.
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Analysis
by VulDB Data Team • 04/18/2024
The vulnerability identified as CVE-2019-17559 represents a critical security flaw in Apache Traffic Server affecting multiple version ranges including 6.0.0 through 6.2.3, 7.0.0 through 7.1.8, and 8.0.0 through 8.0.5. This issue stems from improper handling of HTTP request parsing and scheme validation within the traffic server's proxy functionality, creating opportunities for attackers to manipulate request routing and potentially bypass security controls. The vulnerability specifically targets the server's ability to correctly interpret and process HTTP schemes and request smuggling scenarios that could lead to unauthorized access patterns.
The technical implementation of this vulnerability resides in the HTTP request parsing logic where Apache Traffic Server fails to properly validate scheme information during request processing. When processing incoming HTTP requests, the server does not adequately sanitize or validate the scheme component of URLs, allowing attackers to craft malicious requests that exploit inconsistencies in how different scheme values are interpreted. This weakness enables attackers to manipulate the proxy's behavior by injecting or modifying scheme information in ways that could cause the server to route requests incorrectly or bypass normal security validation checks. The flaw operates at the application layer and specifically affects the HTTP protocol handling mechanisms within the traffic server's core proxy functionality.
The operational impact of CVE-2019-17559 extends beyond simple request manipulation as it creates potential pathways for more sophisticated attacks including cache poisoning, request smuggling, and unauthorized content access. Attackers could leverage this vulnerability to bypass authentication mechanisms, access restricted resources, or manipulate how requests are forwarded through the proxy infrastructure. The vulnerability's presence in widely deployed versions of Apache Traffic Server means that organizations using these affected releases face significant risk of exploitation, particularly in environments where the proxy server handles sensitive traffic or serves as a gateway for internal systems. This issue particularly affects web applications that rely on proper HTTP scheme validation for security enforcement.
Organizations should immediately upgrade to Apache Traffic Server versions 7.1.9 or 8.0.6 and later to remediate this vulnerability, as these releases contain the necessary patches to address the scheme parsing inconsistencies. The upgrade process should include comprehensive testing to ensure that existing proxy configurations continue to function correctly after the patch implementation. Security teams should also implement network monitoring to detect anomalous request patterns that might indicate exploitation attempts, while reviewing proxy logs for evidence of malformed requests that could indicate attempts to leverage this vulnerability. Additionally, organizations should consider implementing additional layers of security controls including web application firewalls and request validation mechanisms to provide defense-in-depth against potential exploitation attempts.
This vulnerability aligns with CWE-444, which describes improper handling of HTTP requests and responses, and represents a variant of HTTP request smuggling attacks that have been documented in various security frameworks. The ATT&CK framework categorizes this issue under T1071.002 for application layer protocol manipulation, and T1566 for malicious command and control communication that could result from successful exploitation. The vulnerability demonstrates the importance of proper input validation and scheme handling in proxy server implementations, highlighting the need for robust protocol parsing mechanisms that can withstand adversarial input manipulation attempts.