Stuxnet – Modus Operandi Liam O Murchu Operations Manager, Symantec Security Response

1

March 2011

Agenda

Stuxnet – Getting to the target 2

Time Line 1

Versions - what changed 2

Targets - Initial and Final 3

Success 4

Techniques – moving from initial to final target 5

Stuxnet Features

• Discovery disclosed in July, 2010

• Attacks industrial control systems likely an Iranian uranium enrichment facility

• Modifies and hides code on Siemens PLCs connected to frequency converters

• Contains 7 methods to propagate, 4 zero day exploits, 1 known exploit, 3 rootkits, 2 unauthorized certificates, 2 Siemens security issues.

• 3 versions, June 2009, March 2010, April 2010

Stuxnet - Sabotaging Industrial Control Systems 3

Stuxnet’s Targets

Stuxnet – Getting to the target 4

Iranian Uranium Enrichment facilities

58.31

17.83

9.96

3.40 1.40 1.16 0.89 0.71 0.61 0.57

5.15

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

Un

iqu

e IP

s C

on

tact

C&

C S

erv

er

(%)

Geographic Distribution of Infections

Frequency Converters

Fararo Paya

Iranian built

5

S7-315 CPU CP-342-5 – 6 modules

. . .

. . .

. . .

Totaling up to 186 motors

Stuxnet’s Targets Intended Final Target

. . . . . .

31 Vacon or Fararo Paya frequency converters per module

Stuxnet - Sabotaging Industrial Control Systems

Data Analysis

• Samples:

– Information about each infected

computer is stored in each sample

– Time stamps of the files tell us when

the Stuxnet project occurred.

• Command and control

servers statistics

Stuxnet Modus Operandi 6

2%

47%

51%

Stuxnet Version Distribution

June 22 2009

March 01 2010

April 13 2010

1%

86%

3% 4%

6%

Stuxnet OS Distribution Win2k

WinXp

WinXp 64bit

Vista

Win 7

05

1015202530

Stuxnet Days before Infection

Stuxnet Timeline

Stuxnet - Sabotaging Industrial Control Systems 7

2008 | Jun | 2009 | Jan | Jun | 2010 | Mar| Apr | Jun

June 2008 Programming of

Stuxnet has begun.

June 22 2009 First Version of Stuxnet is compiled. It is ready to be

released. June 22 2009 First infection of Stuxnet occur in Iran less than 24 hours after the code was

compiled.

Jan 2010 Some components for a new version of Stuxnet

are completed.

Infections occurring at a moderate rate.

April 2010 Another new version of

Stuxnet released. Jan 2009 Some components have

been completed.

March 2010 First infection from this version occur.

Spreads very quickly.

March 2010 New version complete.

USB zero day code added.

May 2010 Infections from new

version start.

June/July 2010 Stuxnet Discovered.

Versions

• June 2009

– only moderate infection numbers

• March 2010

– Spreads very quickly

– Removed old OS’s

– Added USB zero day

• April 2010

– Extended time to live

– Extended spread time for USB

Stuxnet Modus Operandi 8

Initial Targets

• 5 organizations with a presence in Iran targeted

• All involved in Industrial processing

• None are Natanz

• No direct access to Uranium enrichment facility

• Infect someone close to Uranium enrichment process

• Piggy back into the facility when that person visits/interacts with someone at the facility

• One organization targeted by all 3 versions

Stuxnet Modus Operandi 9

Stuxnet Methodology

• No direct access to target

• Infect organizations that interact with target

• Study how these organizations interact

• Get insider knowledge of facilities layout

– Plc type, Hardware in use, etc

• Create aggressive spreading worm to target :

– The relationships of trust

– The actual physical layout

Stuxnet Modus Operandi 10

Success

• 1 year undiscovered – first released in June 2009

• 4 zero days – first time any threat has done this

• Reliable code – professionally written code

• PLC codes appears to work

• Signed drivers – stolen certificates

• > 100,000 infected machine before discovery mostly in Iran

• IAEA report 1000 centrifuges with drawn from service

– Unknown if Stuxnet caused this..??

Stuxnet Modus Operandi 11

Stuxnet Failures

• Discovered 3 months after USB zero day added

• No report of centrifuges out of action since March

• Gained high media attention

• Analysis performed

• Iranian authorities aware

• Traces left in code

Stuxnet – Getting to the target 12

How Stuxnet Attacks

Stuxnet uses 7 different methods to propagate!

1. USB drives – Zero Day

2. Print Spooler Vuln – Zero Day

3. Ms08-067 Vuln

4. Network Shares

5. P2P sharing

6. Wincc Hard coded Password

7. Step7 projects

13 Stuxnet – Getting to the target

Control PC

Attack Execution

Stuxnet – Getting to the target 14

Air Gap

Corporate LAN

Internet Etc 1. Initial Delivery

3. Reporting

Updates 2. Network Exploits

4. Bridge

AirGap 5. Deliver Payload

Self-Replication Step 7 Project Files

Stuxnet - Sabotaging Industrial Control Systems 15

MyProject.s7p

ApiLog

types

hOmSave7

S7HK40AX

S7HK41AX

…

xutils

links

listen

…

+00 WORD count

+02 BYTE[] records

types:

DB 14 14 00 00 00 00 00

00 00 00 00

+00 WORD count

+02 BYTE[] records

• %Step7%\S7BIN

• %SYSTEM32%

• %SYSTEM%

• %WINDIR%

• project's hOmSave7/* subdirectories

s7hkimdb.dll s7hkimdb.dll

s7hkimdb.dll

xr000000.mdx (encrypted Stuxnet)

s7p00001.dbf (Stuxnet datafile)

s7000001.mdx (Stuxnet config data file)

New Version

• Not simple to create new version

• Cannot just drop in new zero days

• Target specific information required

• PLC programming knowledge

• Exploit knowledge

• Real danger is the idea

• Now people know it can be done

• People can start their own projects knowing it is possible

Stuxnet – Getting to the target 16

Solutions & lessons learned

• Insider/Contractor threat is significant

• IP is extremely valuable, protect it at all costs

• Monitor systems and networks

• Watch for red flags

• Accept that network separation is not possible and protect computers inside the traditional air gap more vigorously

• White listing, behavior blocking and reputation based solutions can mitigate threat.

• Device blocking – USBs, contractor laptops, etc..

• Vigilance is key

Stuxnet – Getting to the target 17

Response

• Need dedicated resources in place in advance that can switch focus to a new threat quickly

• Need engineers who are familiar with the latest developments in the threat landscape

• Need to respond quickly – critical infrastructure may be at risk

• Private public partnership will be important

• Growing market

• We will see more of these types of threats in the future, need to prepare for that.

Stuxnet – Getting to the target 18

Summary

• Stuxnet is the first publicly known malware to intend real-world damage

• Required resources at the level of a government

• While as a whole extremely sophisticated, the technique to inject code into PLCs is not

• Enterprises should assume attackers know how these systems work

• Has changed our job at Symantec

• We expect to see more of these threats

Stuxnet – Getting to the target 19

White Paper Available

• Stuxnet Technical Details Available here:

• http://www.symantec.com/content/en/us/enterprise/media/security_response/whitepapers/w32_stuxnet_dossier.pdf

Stuxnet – Getting to the target 20

W32.Stuxnet Dossier

Thank you!

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Thank you!

Stuxnet – Getting to the target 21

Liam O Murchu - liam_omurchu@symantec.com