An attacker is able to leverage access gained to the database to read /
write data to the file system, compromise the operating system, create a
tunnel for accessing the host machine, and use this access to potentially
attack other machines on the same network as the database machine.
Traditionally SQL injections attacks are viewed as a way to gain
anauthorized read access to the data stored in the database, modify the data
in the database, delete the data, etc. However, almost every data base
management system (DBMS) system includes facilities that if compromised
allow an attacker complete access to the file system, operating system, and
full access to the host running the database. The attacker can then use this
privileged access to launch subsequent attacks.
These facilities include dropping into a command shell, creating user
defined functions that can call system level libraries present on the host
machine, stored procedures, etc.
Attack Prerequisites
A vulnerable DBMS is used
A SQL injection exists that gives an attacker access to the database or an
attacker has access to the DBMS via other means
Attacker Skills or Knowledge Required
Skill or Knowledge Level: High
Low level knowledge of the varoius facilities available in different
DBMS systems for interacting with the file system and operating
system
Solutions and Mitigations
Design: Follow the defensive programming practices needed to protect an
application accessing the databae from SQL injection
Configuration: Ensure that the DBMS is patched with the latest security
patches
Design: Ensure that the DBMS login used by the application has the lowest
possible level of privileges in the DBMS
Design: Ensure that DBMS runs with the lowest possible level of privileges
on the host machine and that it runs as a separate user
Usage: Do not use the DBMS machine for anything else other than the
database
Usage: Do not place any trust in the database host on the internal
network. Authenticate and validate all network activity originating from the
database host.
Usage: Use an intrusion detection system to monitor network connections
and logs on the database host.
Implementation: Remove / disable all unneeded / unused functions of the
DBMS system that may allow an attacker to elevate privileges if
compromised
Bernardo Damele Assumpcao Guimaraes.
"Advnced SQL Injection to Operating System Full
Control". http://www.blackhat.com/presentations/bh-europe-09/Guimaraes/Blackhat-europe-09-Damele-SQLInjection-whitepaper.pdf. 2009-04-10.
Description
