Vulnerability Note VU#630091

Oracle9i Database TNS Listener vulnerable to buffer overflow via SERVICE_NAME parameter

Overview

A buffer overflow vulnerability exists in the TNS Listener component of Oracle9i Database. This vulnerability could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the TNS Listener process or cause a denial of service.

I. Description

Oracle9i Database authenticates and manages database connections via Oracle Transparent Network Substrate (TNS ) Listeners. According to a report by NGSSoftware, a buffer overflow condition occurs when a TNS Listener process attempts to log an error condition caused by a TNS request containing an overly long SERVICE_NAME parameter. An attacker may be able to exploit this vulnerability by sending a specially crafted TNS request to a vulnerable Oracle Listener.

According Oracle Security Alert #34, Microsoft Windows and IBM VM versions of Oracle9i Database (9.0.x) are affected by this vulnerability.

II. Impact

An unauthenticated remote attacker could execute arbitrary code or cause a denial of service on a vulnerable system. Oracle Listener processes may run with SYSTEM privileges on Windows NT and Windows 2000 systems.

III. Solution

Apply a Patch

Oracle Security Alert #34 provides information on patches that address this vulnerability.

Restrict Access

Where possible, limit access to trusted users, hosts, and networks. Use firewall or router ACLs (access control lists) to restrict connections to the port used by Oracle TNS Listeners, 1521/tcp by default. Enable the Oracle Net feature called "TCP valid node checking" by modifying $ORACLE_HOME/NETWORK/ADMIN/SQLNET.ORA ($ORACLE_HOME/NETWORK/ADMIN/PROTOCOL.ORA in Oracle8i and prior releases) as follows:

tcp.validnode_checking = YES

tcp.invited_nodes = {list of IP addresses}

tcp.excluded_nodes = {list of IP addresses}

Note that restricting access to Oracle TNS Listeners will not prevent exploitation of this vulnerability.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Oracle	Vulnerable	13-Jun-2002

References

http://www.nextgenss.com/vna/ora-lsnr.txt
http://www.nextgenss.com/advisories/oratns.txt
http://technet.oracle.com/deploy/security/pdf/net9_dos_alert.pdf
http://online.securityfocus.com/bid/4845

Credit

The CERT/CC thanks David Litchfield of NGSSoftware for information used in this document.

This document was written by Art Manion.

Other Information

Date Public:	2002-05-27
Date First Published:	2002-06-04
Date Last Updated:	2002-06-13
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Severity Metric:	11.66
Document Revision:	34

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