Oracle Extproc Buffer Overflow

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             AUSCERT External Security Bulletin Redistribution

      ESB-2003.0516 -- NGSSoftware Insight Security Research Advisory
                               NISR25072003
                      Oracle Extproc Buffer Overflow
                               28 July 2003

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                Oracle Extproc
Publisher:              NGSSoftware
Impact:                 Execute Arbitrary Code/Commands
Access Required:        Remote

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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: http://www.oracle.com
Authors: David Litchfield (david@ngssoftware.com)
 Chris Anley (chris@ngssoftware.com)
Date: 25th July 2003
Advisory number: #NISR25072003

Description
***********
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.

Details
*******
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:

http://otn.oracle.com/deploy/security/pdf/2003alert57.pdf

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.

http://www.ngssoftware.com/products/squirrelfororacle.html

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.

http://www.ngssoftware.com/
http://www.ngsconsulting.com/

Telephone +44 208 401 0070
Fax +44 208 401 0076

enquiries@ngssoftware.com

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