Oracle Extproc Buffer Overflow (#NISR25072003)

Type securityvulns
Reporter Securityvulns
Modified 2003-07-25T00:00:00


NGSSoftware Insight Security Research Advisory

Name: Oracle Extproc Buffer Overflow Systems Affected: Most OS platforms; Oracle9i Database Release 2 and 1, 8i Severity: High Risk Vendor URL: Authors: David Litchfield ( Chris Anley ( Date: 25th July 2003 Advisory number: #NISR25072003


Oracle's RDBMS, a leading database server package, supports stored packages and procedures through the use of PL/SQL. These packages and procedures can be extended by allowing calls to be made to operating system libraries. Any library loaded in this way is done so by a process external to the main RDBMS, namely extproc. Extproc is vulnerable to a classic stack based buffer overflow. This can be exploited remotely by an attacker. No user ID or password is necessary.


Previously, NGSSoftware discovered a vulnerability in the Oracle package that allowed an attacker to force extproc to load any operating system library and execute any function. This attack did not require a user ID or password. Oracle took steps to resolve this security hole. By way of fixing the vulnerability, attempts to load libraries would be logged but denied unless the call came from the local machine. Remote attempts would be logged as just stated. However, this logging process is vulnerable to a classic stack based buffer overflow vulnerability. By supplying an overly long library name a stack based buffer is overflowed, overwriting the saved return address on the stack. When the vulnerable procedure returns control over the process' path of execution can be gained. As this does not require a user ID or password it must be stressed that this is a critical vulnerability. On Windows platforms Oracle typically runs in the security context of the LOCAL SYSTEM account and, as such, allows for a complete compromise of the server. On Unix-based systems extproc runs as the 'Oracle' user. As the 'Oracle' user typcially is the owner of the software binaries and data files, an attacker exploiting this can completely subvert the integrity of the database software and data.

Fix Information

NGSSoftware alerted Oracle to this vulnerability on 30th September 2002. Oracle has reviewed the code and created a patch which is available from:

NGSSoftware advise Oracle database customers to review and install the patch as a matter of urgency.

A check for this issue already exists in NGSSQuirreL for Oracle, a comprehensive automated vulnerability assessment tool for Oracle Database Servers of which more information is available from the NGSSite.

It is further recommend that Oracle DBAs have their network/firewall administrators ensure that the database server is protected from Internet sourced traffic.

About NGSSoftware

NGSSoftware design, research and develop intelligent, advanced application security assessment scanners. Based in the United Kingdom, NGSSoftware have offices in the South of London and the East Coast of Scotland. NGSSoftware's sister company NGSConsulting, offers best of breed security consulting services, specialising in application, host and network security assessments.

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