Remote Denial of Service Vulnerability in Oracle9i SQL*NET
Internet Security Systems Security Advisory August, 13, 2002 Remote Denial of Service Vulnerability in Oracle9i SQL*NET Synopsis: ISS X-Force has discovered a flaw in the debugging mechanism of Oracle9i. To exploit this vulnerability, attackers must send a specially crafted request to an Oracle9i SQL*NET listener. Due to an implementation flaw, Oracle9i does not handle the request correctly and fails. All Oracle9i installations are vulnerable to this attack. Impact: A successful attack on a vulnerable server can cause the SQL*NET listener to fail and crash. Database functionality cannot be restored until the listener is manually restarted. Affected Versions: Oracle9i 9.0.x Oracle9i 9.2 Note: All platforms for the affected versions are vulnerable. Description: SQL*NET permits client-server and server-server communication across any network. SQL*NET enables distributed processing of SQL queries as well as access to SQL databases from SQL-enabled clients. Oracle9i has a debugging facility that allows database administrators to collect additional information about the operation of the server. Debugging features are enabled by default and cannot be disabled. The Oracle9i SQL*NET listener does not correctly handle certain types of debug requests that are submitted over the network. If Oracle9i encounters such a request, it will crash and no longer field SQL requests from authorized servers or clients. Recommendations: Oracle recommends that affected customers evaluate the possibility of enabling "Valid Node Checking." This feature allows database administrators to restrict access to the SQL*NET listener to only authorized clients and servers. While this feature will not block successful exploitation, it will limit exposure to this vulnerability. Refer to Oracle Security Alert #38 for more information about this workaround. RealSecure Network Sensor X-Press Update 5.1 and 20.2 includes an event, Oracle_Listener_Debug_DoS, to detect exploitation attempts. XPU 5.1 and 20.2 are available from the ISS Download Center at: http://www.iss.net/download. For questions about downloading and installing this XPU, email support@iss.net. ISS X-Force recommends that all Oracle customers maintain a current patch level on their Oracle installations. Oracle has released a patch for this issue and it is available through Oracle¿ Worldwide Support Services website at: http://metalink.oracle.com. Customers can reference this issue with the bug number 2467947. X-Force further recommends that the SQL*NET port TCP/1521 is filtered at all border gateways to limit access to the Oracle listener and mitigate the risk of this vulnerability. The default SQL*NET port is TCP 1521, however this port is configurable. Additional Information: Oracle Security Alert #38 http://metalink.oracle.com Internet Security Systems X-Force Database http://www.iss.net/security_center/static/9237.php The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2002-0856 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. Credits: This vulnerability was discovered and researched by Ben Layer of the ISS X-Force. ______ About Internet Security Systems (ISS) Founded in 1994, Internet Security Systems (ISS) (Nasdaq: ISSX) is a pioneer and world leader in software and services that protect critical online resources from an ever-changing spectrum of threats and misuse. Internet Security Systems is headquartered in Atlanta, GA, with additional operations throughout the Americas, Asia, Australia, Europe and the Middle East. Copyright (c) 2002 Internet Security Systems, Inc. All rights reserved worldwide. Permission is hereby granted for the electronic redistribution of this document. It is not to be edited or altered in any way without the express written consent of the Internet Security Systems X-Force. If you wish to reprint the whole or any part of this document in any other medium excluding electronic media, please email xforce@iss.net for permission. Disclaimer: The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (Internet Security Systems X-Force) be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information. X-Force PGP Key available on MIT's PGP key server and PGP.com's key server, as well as at http://www.iss.net/security_center/sensitive.php Please send suggestions, updates, and comments to: X-Force xforce@iss.net of Internet Security Systems, Inc.