CVE-2001-0498 in Oracle
Summary
by MITRE
Transparent Network Substrate (TNS) over Net8 (SQLNet) in Oracle 8i 8.1.7 and earlier allows remote attackers to cause a denial of service via a malformed SQLNet connection request with a large offset in the header extension.
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Analysis
by VulDB Data Team • 05/17/2019
The vulnerability described in CVE-2001-0498 targets the Transparent Network Substrate implementation within Oracle 8i 8.1.7 and earlier versions, specifically affecting the Net8 SQLNet protocol component. This flaw resides in the network layer processing of Oracle database systems, where the TNS protocol handles client-server communication over network connections. The vulnerability manifests when the system receives a malformed SQLNet connection request that contains an oversized offset value within the header extension field, creating a condition that can be exploited by remote attackers to disrupt normal service operations.
The technical mechanism behind this vulnerability involves improper input validation within the TNS listener component of Oracle's Net8 architecture. When processing incoming connection requests, the system fails to adequately validate the offset field in the header extension, allowing an attacker to craft malicious packets with excessively large offset values. This condition causes the TNS listener to enter an undefined state where it cannot properly process subsequent legitimate connection requests, leading to a denial of service condition that affects the availability of database services. The flaw is classified as a buffer over-read condition where the system attempts to access memory locations beyond the allocated buffer boundaries, potentially causing system instability or complete service termination.
The operational impact of this vulnerability extends beyond simple service disruption as it affects critical database infrastructure components that support enterprise applications. Organizations running affected Oracle versions experience potential downtime that can severely impact business operations, particularly in environments where database availability is paramount for transactional systems, web applications, and enterprise resource planning solutions. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter without requiring authentication credentials, making it particularly dangerous for publicly exposed database servers. This vulnerability directly impacts the availability component of the CIA triad and can result in significant financial losses due to extended downtime and potential data access interruptions.
Mitigation strategies for this vulnerability require immediate implementation of Oracle's security patches and updates, specifically targeting the TNS listener components in affected Oracle 8i versions. System administrators should implement network segmentation and access controls to limit exposure of database servers to untrusted networks, while also configuring firewalls to restrict unnecessary database port access. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic example of improper input validation that can lead to denial of service attacks. Organizations should also consider implementing intrusion detection systems to monitor for anomalous connection patterns that might indicate exploitation attempts. Additionally, following the ATT&CK framework's T1499 technique for network denial of service, security teams should establish monitoring protocols to detect and respond to malformed connection requests that could be indicative of this specific vulnerability being targeted. The patching process should be prioritized as a critical security measure, as this vulnerability does not require authentication and can be exploited by any remote attacker with network access to the affected Oracle database systems.