CVE-2002-0566 in Oracle9i
Summary
by MITRE
PL/SQL module 3.0.9.8.2 in Oracle 9i Application Server 1.0.2.x allows remote attackers to cause a denial of service (crash) via an HTTP Authorization header without an authentication type.
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Analysis
by VulDB Data Team • 09/16/2025
The vulnerability identified as CVE-2002-0566 represents a denial of service weakness in Oracle 9i Application Server version 1.0.2.x, specifically within the PL/SQL module version 3.0.9.8.2. This flaw manifests when the server receives an HTTP Authorization header that lacks a proper authentication type specification, leading to a system crash that effectively denies service to legitimate users. The vulnerability operates at the application layer of the network stack and demonstrates a classic buffer handling or input validation weakness that can be exploited remotely without requiring authentication credentials. The issue stems from inadequate parsing of HTTP headers, particularly those related to authentication mechanisms, where the system fails to properly handle malformed or incomplete authorization data. According to CWE classification, this vulnerability maps to CWE-20, which addresses improper input validation, and CWE-119, which deals with improper access to memory locations. The attack vector is classified as network-based remote exploitation, making it particularly dangerous as it can be triggered from any location on the internet without requiring physical access to the target system. The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially be leveraged as a precursor to more sophisticated attacks or as part of a larger exploitation campaign targeting Oracle application servers.
The technical exploitation of this vulnerability requires sending a specially crafted HTTP request containing an Authorization header that omits the authentication type specification, such as Basic, Digest, or other supported authentication schemes. When the Oracle 9i Application Server processes this malformed header, the PL/SQL module fails to properly validate the input and attempts to process the incomplete data structure, leading to an application crash or segmentation fault. This behavior is consistent with the ATT&CK framework's T1499.004 technique, which involves network denial of service attacks through application layer manipulation. The vulnerability affects systems that rely on the default authentication handling mechanisms of Oracle 9i Application Server and demonstrates a fundamental lack of robust error handling in the HTTP request processing pipeline. The crash occurs during the authentication phase of the HTTP request lifecycle, indicating that the issue is not merely cosmetic but represents a critical failure in the application's ability to gracefully handle malformed input data. Security researchers have noted that this type of vulnerability often indicates broader architectural weaknesses in how the application server handles protocol-level data structures and input validation routines.
Organizations utilizing Oracle 9i Application Server 1.0.2.x are advised to implement immediate mitigations while planning for comprehensive patching. The most effective immediate solution involves configuring network firewalls and intrusion prevention systems to filter and block malformed HTTP requests containing Authorization headers without proper authentication type specifications. Additionally, implementing rate limiting and connection throttling mechanisms can help reduce the impact of potential exploitation attempts. The vulnerability aligns with the ATT&CK technique T1566.001, which involves spearphishing with embedded malicious content, as attackers may attempt to use this weakness as part of broader reconnaissance efforts. System administrators should also consider implementing application-level monitoring to detect unusual patterns of authentication-related crashes or service disruptions that could indicate exploitation attempts. The vulnerability's classification as a denial of service weakness means that traditional antivirus solutions may not detect or prevent exploitation, requiring network-level defensive measures and application monitoring. Organizations should also review their incident response procedures to ensure they can quickly identify and respond to service disruption events that may be related to this specific vulnerability. Long-term mitigation strategies should include upgrading to patched versions of Oracle 9i Application Server, as Oracle released security updates specifically addressing this flaw in subsequent releases. The vulnerability demonstrates the importance of robust input validation and proper error handling in enterprise application servers, particularly those handling network-based authentication protocols.