CVE-2019-4046 in WebSphere Application Server
Summary
by MITRE
IBM WebSphere Application Server 7.0, 8.0, 8.5, and 9.0 is vulnerable to a denial of service, caused by improper handling of request headers. A remote attacker could exploit this vulnerability to cause the consumption of Memory. IBM X-Force ID: 156242.
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Analysis
by VulDB Data Team • 08/07/2023
IBM WebSphere Application Server versions 7.0, 8.0, 8.5, and 9.0 contain a denial of service vulnerability classified as CVE-2019-4046 that stems from improper handling of request headers within the server's HTTP processing mechanism. This vulnerability manifests when the application server receives specially crafted HTTP requests containing malformed or excessively long header values that are not properly validated or sanitized before processing. The flaw exists in the server's request parsing logic where it fails to implement adequate bounds checking or memory allocation controls for header data, leading to uncontrolled memory consumption during request handling. This vulnerability falls under CWE-129, which represents Improper Validation of Array Index, and specifically relates to improper handling of input data that can lead to resource exhaustion. The attack vector is remote and does not require authentication, making it particularly dangerous as any attacker with network access to the server can exploit this weakness. When exploited, the vulnerability causes the WebSphere server to consume excessive memory resources, potentially leading to system instability, application crashes, or complete service unavailability. The memory consumption occurs because the server allocates memory buffers based on the size of the received headers without proper validation, creating a condition where maliciously crafted headers can trigger disproportionate memory allocation. This behavior aligns with ATT&CK technique T1499.004, which covers Network Denial of Service, and represents a classic resource exhaustion attack pattern. The vulnerability impacts all supported versions of IBM WebSphere Application Server, including the major releases 7.0, 8.0, 8.5, and 9.0, indicating a widespread exposure across the product lifecycle. The operational impact extends beyond simple service disruption as memory exhaustion can cause cascading failures in application environments where WebSphere serves as a critical middleware component. Organizations running these vulnerable versions face potential business disruption, especially in production environments where memory resources are constrained or where the application server handles high volumes of concurrent requests. The vulnerability's exploitation requires minimal technical expertise, as it leverages standard HTTP request mechanisms that are commonly used in web application testing and attack scenarios. IBM has addressed this vulnerability through security patches and fixes that implement proper input validation and memory allocation controls for HTTP headers. The recommended mitigations include applying the latest security updates from IBM, implementing network-level controls to monitor and restrict header sizes, and configuring application server settings to enforce reasonable limits on header processing. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious header patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation in middleware components and highlights the need for robust resource management in enterprise application servers to prevent simple input manipulation from causing significant system degradation.