CVE-2002-1118 in Oracle
Summary
by MITRE
TNS Listener in Oracle Net Services for Oracle 9i 9.2.x and 9.0.x, and Oracle 8i 8.1.x, allows remote attackers to cause a denial of service (hang or crash) via a SERVICE_CURLOAD command.
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Analysis
by VulDB Data Team • 05/24/2019
The vulnerability identified as CVE-2002-1118 affects the TNS Listener component within Oracle Net Services across multiple Oracle database versions including 8i 8.1.x, 9i 9.0.x, and 9.2.x releases. This represents a significant security weakness in Oracle's network services architecture that enables remote attackers to disrupt database operations through specifically crafted network commands. The TNS Listener serves as a critical intermediary component that handles client connections to Oracle database servers, making this vulnerability particularly dangerous as it can be exploited from remote locations without requiring authentication or prior access to the system. The flaw specifically manifests when the listener processes a SERVICE_CURLOAD command, which is part of Oracle's network protocol implementation for managing service load information.
The technical nature of this vulnerability stems from inadequate input validation and error handling within the TNS Listener's command processing mechanism. When a remote attacker sends a malformed SERVICE_CURLOAD command to the listener, the system fails to properly validate the command structure or handle the unexpected input gracefully. This leads to the listener entering an undefined state where it either hangs indefinitely or crashes completely, resulting in a denial of service condition that prevents legitimate database clients from establishing connections. The vulnerability demonstrates poor defensive programming practices where the system does not implement proper bounds checking or input sanitization for network commands received through the TNS protocol. This weakness aligns with CWE-129, which addresses improper validation of input boundaries, and CWE-248, which covers exposure of unintended alternative execution paths.
The operational impact of CVE-2002-1118 extends beyond simple service disruption to potentially compromise business continuity and data availability for organizations relying on Oracle database systems. When the TNS Listener becomes unresponsive or crashes, all database access is effectively blocked until the service is manually restarted or the system is rebooted, creating significant downtime for applications and users dependent on database services. This vulnerability can be particularly damaging in production environments where database availability is critical for business operations, potentially resulting in substantial financial losses and service degradation. Attackers can exploit this vulnerability with minimal technical expertise since it requires only basic network connectivity and knowledge of Oracle's TNS protocol structure. The remote nature of the attack means that organizations cannot rely on network segmentation or traditional perimeter security measures to prevent exploitation, as the vulnerability can be triggered from any location with network access to the affected listener port.
Organizations affected by this vulnerability should implement immediate mitigations including applying Oracle's security patches and updates released to address the specific TNS Listener issue. Network segmentation strategies should be enhanced to limit access to TNS listener ports only to trusted networks and systems, while firewall rules should be configured to restrict connections to these ports from unauthorized sources. The implementation of intrusion detection systems capable of monitoring for suspicious TNS protocol activity can provide early warning of potential exploitation attempts. Additionally, organizations should consider disabling unnecessary services and features, particularly when the TNS Listener is not required for specific database configurations. From a security monitoring perspective, regular audits of listener configurations and network access controls should be conducted to ensure that only authorized systems can communicate with database services. This vulnerability serves as a reminder of the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that protect critical database infrastructure from both known and emerging threats. The ATT&CK framework categorizes this vulnerability under the Tactic of Defense Evasion and the Technique of Service Stoppage, highlighting how attackers can leverage system weaknesses to create operational disruptions that may mask more sophisticated attack activities.