December 17, 2008
Laptop Data Protection
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Agenda
Scope of the problemData encryption toolkitLaptop threats discussion
Stolen government laptop held patient data Records of 2,500 taking part in a medical study went missing last month
Laptop Stolen With 22,000
Patients' Data
NHS laptop with 5,123 patient records stolen
Mental Health
Clinic Loses
Laptop Bearing
Patient Data
Up to 3,000 patients' data stolen
The details of up to 3,000
NHS patients could have
been on a computer stolen
from a doctors' surgery.
Hospital Chain
Loses Patient
Data
Stolen Laptop
Contains Unsecured
Data on 365,000
Patients
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“Workers will average nearly 40% of their time away from the
desk – a factor that will massively play into mobilizing millions of
corporate inboxes this year.”
Strategy Analytics, “Mobile business Application Outlook”, January 2006
“In 2006 we estimate the number of mobile professionals
(defined as spending at least 20% of their time away…) will
grow to roughly two thirds of workers.”
Strategy Analytics, “Mobile Business Application Outlook”, January 2006
“The worldwide mobile worker population is set to
increase to 878.2 million in 2009, accounting for
27.3% of the workforce.”
Strategy Analytics, “Mobile business Application Outlook”, January 2006
And so..
The Laptop Data Protection Solution Accelerator was born
The goal of the guide is to help customers secure the data on their mobile (and desktop) computers
http://technet.microsoft.com/en-us/library/cc500474.aspx
Microsoft Vision:
“When a customer loses a laptop, they only lose
a laptop.”
Trustworthy Computing:
“The security of our customers' computers and networks is a
top priority, and we are committed to building software and
services to better help protect our customers and the
industry.” Microsoft
The threats discussed in this presentation are not secrets
Our customers‟ adversaries are aware of these attack
vectors
Our customers need this information too, so that they may
make informed decisions about the level of data
protection that they need
Online attacks
With BitLocker, data is protected when the system is shutdown (protecting against offline attacks)
When the system is started, the keys are loaded and available in memory
Same thing if the system is in sleep mode (S3 standby)
Goal: Get the keys from memory
Online attacks..Warm Ghosting
Attacker boots systemAttacker warm reboots into OS which avoids destruction of RAM imageAttacker then can access ghost secrets in Memory
Cold Ghosting / Iceman attackPhysical memory cells may retain charge long enough to be copied
Battery backed DIMMs make it easy!Recent research made headlines but nothing “really” new…
http://citp.princeton.edu.nyud.net/pub/coldboot.pdf
Online Attacks..
Direct memory access via physical interfaces
PCI bus Exploit with PC Card & DMA (David Hulton, ShmooCon 2006)
Firewire / IEEE 1394 (allows physical access to host memory)
Firewire Attack
Adam Boileau, RuxCon 2006
Full Memory Dump via Firewireinterface
Leads to dump analysis to find the Bitlocker keys
Linux Target Vista, online
Firewire
Threats against the TCB
Core Root of Trust for Measurement (CRTM) is intended to be „immutable‟ portion of BIOS
Attacking the CRTM
Execute chosen-code in CRTM
Control / prevent measurements
Physically remove it
Attack existing CRTM (e.g. buffer overrun)
Attack secure update-mechanism to inject unauthorized code into CRTM
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Premeditated Attacks
Attacker hobbles BitLocker protection prior to laptop loss or theft
There are many advance-strikes
BitLocker does not protect against boot rootkits that are BitLocker-aware
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Bitlocker: Key Protection mechanisms
Security
Ea
se
of U
se TPM Only
“What it is.”
Protects
against: SW-
only attacks
Vulnerable to:
HW attacks
TPM + PIN
“What you
know.”
Protects
against: Many
HW attacks
Vulnerable to:
TPM breaking
attacks
Dongle Only
“What you
have.”
Protects
against: All HW
attacks
Vulnerable to:
Losing dongle
Pre-OS attacks
TPM +
Dongle
“Two what I
have’s.”
Protects
against:
Many HW
attacks
Vulnerable to:
HW attacks
TPM + PIN +
Dongle
“Two what I
have’s, One I
know.”
Vista SP1,
Server 2008
only
Advanced modes
Vista SP1\2008 Mitigations:Use bitlocker advanced modes with hibernation - Group policy for hibernateEnsure BIOS meets bitlocker standardsDisable 1394 and PCI host controllers
• http://blogs.msdn.com/si_team/archive/2008/02/25/protecting-bitLocker-from-cold-attacks-and-other-threats.aspx
Require smartcards for logon or use strong passwordsUse EFS + smartcard to protect user data
• After “x” bad tries, Smart Card locked FOREVER
Defence in depth:
EFS: Mitigates offline attacks except against user accountPrevents online attacks (on encrypted files)Threats switch to user‟s password
BitLocker with advanced modesPrevents offline attacks (replace passwords, read hashes)Threats switch to user logons
Ideal: BitLocker (+USB+Pin)+ EFS with Smart CardAttacker with notebook + Smart Card needs PINAfter “x” bad tries, Smart Card locked FOREVER
Pre-Vista SP1\2008:SYSKEY in mode 2 or 3 (can be used on XP\2000 etc) Key stored in your head (mode 2) Key stored on a floppy (mode 3)
Protects password hashes with 128 bit symmetric encryption Either mode prevents „Nordahl‟ boot-disk attacks Also prevents the DS Restore mode style attacks
Threat – Attacks on Passwords
Password guessing: Any services that exposes authentication protocols
are at risk for password guessing attacks
NetBIOS, SMB, RDP, IIS, FTP etc.
Online attacks:Dumping password hashes from LSASS while the operating system is running
• Pwdump*.exe, L0phtCrack 5, GSecDump• http://truesecurity.se/blogs/murray/default.aspxMust have admin access for this to work
Threats against Passwords
Man In the Middle AttacksSniffing shared-secret authentication exchanges based on a users password between client / server (LM, NTLMv2, Kerberos)
• Tools available for LM/NTLM and Kerberos v5: ScoopLM
BeatLM /Kerbcrack/ LC5
Threats against Passwords
MitigationsMake your hashes immune to reversing in any reasonable amount of time.
Use 10 (or 15) character or stronger complex passwords• Or better yet pass-phrases!
• NT based operating systems support 128 character pass-phrases
• Use two factor authentication
Change them every 90 days or less.
Minimum time before password can be changed 1 day
Number of previous passwords remembered: at least 24Run in least privilegeShutdown un-needed services (Server service, FTP service etc.)