CVE-2003-0634 in Oracle8i
Summary
by MITRE
Stack-based buffer overflow in the PL/SQL EXTPROC functionality for Oracle9i Database Release 2 and 1, and Oracle 8i, allows authenticated database users, and arbitrary database users in some cases, to execute arbitrary code via a long library name.
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Analysis
by VulDB Data Team • 08/12/2025
The vulnerability identified as CVE-2003-0634 represents a critical stack-based buffer overflow affecting Oracle database systems, specifically targeting the PL/SQL EXTPROC functionality within Oracle9i Database Release 2 and 1, as well as Oracle 8i installations. This flaw resides in the database's external procedure calling mechanism, which allows database applications to invoke external programs written in languages such as C or C++. The vulnerability manifests when the system processes a library name that exceeds the allocated buffer space, creating conditions where malicious input can overwrite adjacent memory locations on the stack. The affected component operates at the interface between the database engine and external executables, making it a prime target for exploitation as it bridges the database security boundary with the operating system level processes.
The technical implementation of this vulnerability stems from insufficient input validation within the EXTPROC functionality where library names are processed without adequate bounds checking. When an authenticated database user submits a specially crafted library name exceeding the predefined buffer limits, the system's stack memory management fails to prevent the overflow condition. This buffer overflow occurs because the implementation does not properly validate the length of the input string before copying it into a fixed-size buffer, creating a classic stack corruption scenario that can be exploited by malicious actors. The flaw specifically impacts the way Oracle handles external procedure calls, where the system attempts to load and execute external libraries through the EXTPROC mechanism, making the vulnerability accessible through legitimate database access points.
The operational impact of CVE-2003-0634 extends beyond simple privilege escalation as it provides attackers with the capability to execute arbitrary code with the privileges of the database service account. This can lead to complete system compromise, data exfiltration, and unauthorized access to sensitive information stored within the database environment. The vulnerability's accessibility varies based on deployment configurations, as authenticated database users can exploit it directly, while in certain scenarios, even unauthenticated users may gain access through specific attack vectors. The attack surface is particularly concerning because EXTPROC functionality is commonly enabled in production environments, making the vulnerability exploitable in real-world database deployments. The potential for remote code execution through database connections makes this vulnerability particularly dangerous in networked environments where database services are exposed to external networks.
Mitigation strategies for CVE-2003-0634 should prioritize immediate patch application from Oracle, as the vendor released security updates specifically addressing this buffer overflow condition. Organizations must disable EXTPROC functionality when not required, as this removes the attack surface entirely and prevents exploitation of the vulnerability. Access controls should be strictly enforced to limit database user privileges and prevent unauthorized access to database resources that could facilitate exploitation attempts. Network segmentation and firewall rules should restrict direct database access from untrusted networks, while monitoring systems should be implemented to detect unusual database activity patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121 stack-based buffer overflow classification and represents a technique commonly mapped to ATT&CK tactics including privilege escalation and execution through database interfaces, making it a critical concern for organizations implementing database security controls.