Hacking MFPs - andreicostin.com - 28C3 - Hacking MFPs (part2) - PostScript_um you_ve...Hacking MFPs PostScript(um–you’ve been hacked) Andrei Costin Andrei:

Hacking MFPs PostScript(umndashyoursquove been hacked)

Andrei Costin ltandreisrlabsdegt

Andrei Hardware hacker amp coder

1

Mifare Classic MFCUK

Hacking MFPs (for fun amp profit) General

ITAPGSM

security

httpandreicostincompapers

Quick Quiz

2

Which vendor do you think this talk is about

(ie Whose MFPs do you think are least secure)

Participating audience results

5 70 20

Agenda

1 Quick refresher

2 What about PostScript

3 So what and how did you find

4 Attacks in a nutshell

5 Solutions and conclusions

3

MFPs carry large abuse potential

4

MFP hacking goes back to the 1960rsquos

5

ldquoSpies in the Xerox machinerdquo

The ldquomicrordquo-film camera marked X

Patent drawing 1967

Electronicshardware hacking

Modern printer hacking goes back almost a decade

6

Broader amp deeper printer hacking (irongeek)

Initial printer hacks (FXpH)

2002 2006

Revived printer hacking interest

This talk focuses mainly on remote code execution inside MFPsprinters

2011

In 2010 we demorsquod mapping public MFPs

7

httpwwwyoutubecomwatchv=t44GibiCoCM

hellip and generic MFP payload delivery using Word

8

httpwwwyoutubecomwatchv=KrWFOo2RAnk (there are false claims of some guys)

hellip and generic MFP payload delivery using Java

9

httpwwwyoutubecomwatchv=JcfxvZml6-Y

Agenda

1 Quick refresher

2 What about PostScript

3 So what and how did you find

4 Attacks in a nutshell

5 Solutions and conclusions

10

PostScript who Itrsquos Adobersquos PDF big brother

11

Adobe is the dominant PS implementation

12

Adobe PS interpreters

Other PS interpreters

Distribution of Postscript interpreters

Source Adobe specification supplement note

PS is build to handle complex processing tasks

13

Graphics amp patterns Complex math Web servers

Ray-tracing OpenGL Milling machine XML Parsers

File systems IO subsystems

PSgt ldquoshellrdquo ndash where

14

From the official Postscript specification ldquo244 Using the Interpreter Interactivelyrdquo

Debugging is enabled on most PS instances

15

PS-executive

debug enabled

PS-executive

debug disabledNA

PSgt ldquoshellrdquo ndash how

16

Code demo ndash telnet 19216801 9100 and dump this

PSgt ldquoshellrdquo ndash how

17

Agenda

1 Quick refresher

2 What about PostScript

3 So what and how did you find

4 Attacks in a nutshell

5 Solutions and conclusions

18

We needed a PS-based firmware upload

19

This is too good to be truehellip

20

VxWorks API vx

DebugQA API QA

Logging API EventLog

BillingMeters API meter

Pump PWM pumppwm

RAMdisk API ramdisk

RAM API ram

Flash API flash

Memory dumping reveals computing secrets

21

Demo

22

Admin restriction fail to prevent memory dumping

23

Demo

24

Basic auth password can be dumped

25

1) Authorization Basic YWRtaW4yOhellip

2) HTTP11 200 OK

HTTPS IPsec secrets are ldquoleakyrdquo as wellhellip

26

0x66306630663066306630663066302222

Demo

27

Attacker has access to printed document details

28

Demo

29

Attacker has access to BSD-style socketshellip

30

Two-way BSD-style sockets communication

Analyzed MFP cannot protect effectively

31

Privilege level separation

Secure password setup

Secure (basic) auth

HTTPS IPSEC secrets protection

Network topology protection

In-memory document protection

Restrict sockets on unprivileged modules

Protection measures Fail warn ok

Plenty of Xerox printers share affected PS firmware update mechanism

32

Agenda

1 Quick refresher

2 What about PostScript

3 So what and how did you find

4 Attacks in a nutshell

5 Solutions and conclusions

33

Remote attacks can be used to extract data

34

Sent

by

email

Drive-

by

print

Stage 1 ndash SocEng Stage 2 - Printing Stage 3 ndash Exploitingspying

Print

attachment

Print

from

web

Malware exploits

internal netw or

extracts data

Spool

malicious

byte

stream

Agenda

1 Quick refresher

2 What about PostScript

3 So what and how did you find

4 Attacks in a nutshell

5 Whatrsquos next solutions conclusions

35

Whatrsquos next PS + MSF + FS + Sockets = PWN

36

Solutions

37

Admins bull Disable Language Operator Authorization bull Look for security bulletins and patch bull Sanbox printers in your network bull Include MFPs in security audit lifecycle

Users bull Do not print from untrusted sources

Vendors bull Create realistic MFP threat models bull Do not enableexpose super-APIs

Actor Suggested actions

Thanksresources

38

Personal thanks

Igor Marinescu MihaiSa Great logistic support and friendly help

Xerox Security Team Positive responses active mitigation

wwwtinajacom Insanely large free postscript resources dir

wwwanastigmatixnet Very good postscript resources

wwwacumentrainingcom Very good postscript resources

Take aways

39

Questions

Andrei Costin andreisrlabsde httpandreicostincompapers

Upcoming MFP attack could include viruses in Office and PS documents that extract organization data

Securing the MFP infrastructure requires better segmentation strong credentials and continious vulnerability patching

MFPs are badly secured computing platforms with large abuse potential

Demo

40

Password setup is sniffed by the attacker

41

1) HTTP request ndash password clear text

2) HTTP reply

Demo

42

Attacker has access to network topology ndash no-scan

43