CVE-2002-0856 in Oracle9i
Summary
by MITRE
SQL*NET listener for Oracle Net Oracle9i 9.0.x and 9.2 allows remote attackers to cause a denial of service (crash) via certain debug requests that are not properly handled by the debugging feature.
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Analysis
by VulDB Data Team • 05/09/2019
The vulnerability identified as CVE-2002-0856 represents a critical denial of service flaw within Oracle Net SQLNET listener components of Oracle9i database versions 9.0.x and 9.2. This issue stems from inadequate handling of specific debug requests that are not properly validated or sanitized by the listener's debugging functionality. The vulnerability falls under the category of improper input validation and insufficient error handling, which are commonly exploited vectors in network service attacks. The SQLNET listener serves as the primary communication interface between client applications and Oracle database servers, making it a crucial component for database operations and system availability.
The technical exploitation of this vulnerability occurs when remote attackers send specially crafted debug requests to the SQL*NET listener service. These requests contain malformed or unexpected parameters that the listener's debugging subsystem cannot properly process, leading to application crashes or service interruptions. The flaw demonstrates characteristics consistent with CWE-20 Improper Input Validation, where the system fails to adequately validate or sanitize input data before processing. The debugging feature, intended for legitimate administrative purposes, becomes a vector for malicious activity when it lacks proper input sanitization mechanisms. This vulnerability specifically affects the listener component's ability to handle exceptional conditions gracefully, resulting in service termination rather than proper error recovery.
The operational impact of CVE-2002-0856 extends beyond simple service disruption, as it can compromise database availability and potentially impact business operations that depend on Oracle database services. When the SQL*NET listener crashes, all database connections through that interface become unavailable until the service is manually restarted, creating significant downtime for database-dependent applications. This vulnerability is particularly concerning in enterprise environments where database availability is critical for business continuity. The attack vector is straightforward and requires minimal technical expertise, making it attractive to attackers seeking to disrupt database services. The vulnerability's classification aligns with ATT&CK technique T1499.004 Network Denial of Service, which specifically addresses attacks targeting network services to deny access to legitimate users.
Organizations affected by this vulnerability should implement immediate mitigations including disabling unnecessary debugging features, applying available security patches from Oracle, and implementing network segmentation to limit exposure of database listener services to untrusted networks. The recommended approach involves configuring access controls to restrict debug request handling to trusted administrative networks only. Additionally, monitoring systems should be enhanced to detect unusual patterns of debug requests that may indicate exploitation attempts. Security administrators should consider implementing intrusion detection systems that can identify malformed debug requests targeting Oracle listener services. The vulnerability also highlights the importance of regular security assessments and patch management procedures to prevent similar issues in other Oracle components and third-party applications that may exhibit similar input validation weaknesses.