Rambling on the Private Data Security

Sun Bingtaoshaixiaoyao@hotmail.com

Syscan’08 Hong Kong China30th May 2008

Preface Nowadays “Private Data Security” has become a v

ery hot topic, especially after the HK entertainment circles celebrity pornogate scandal, so it’s necessary to provide ordinary computer users with knowledges and tools to protect their private data.

A random talk on some “Data Security” related topics, which will mainly focus on the following subjects:

Harddisk Lock Password EFS vs. Windows Vista Bitlocker WaterBox Software (Information Leakage Prevention) Harddisk Protection/Recovery Software/Card

Harddisk Lock Password ATA Security Mode Feature Set

Abusing the Security Feature Set

Harddisk Lock BIOS Configuration of Dell Latitude D620 Laptop

Cracking the Harddisk Lock Password

ATA Security Mode Feature Set Security Mode Feature Set

A password system that restricts access to user data stored on a device. In addition, access to some configuration capabilities is restricted.

Password User Password Master Password

Master Password Capability High Maximum

Frozen ModeThe Security Freeze Lock command prevents changes to all Sec

urity states until a following power-on reset or hardware reset, the purpose of this command is to prevent password setting attacks on the security system.

ATA Security Mode Feature Set (Cont) Commands

Security Set Password Security Unlock (requires a password) Security Erase Prepare Security Erase Unit (requires a password) Security Freeze Lock Security Disable Password (requires a password)

Password RulesSee Table 6

Password Attempt Counter Counter: set to 5 after a power-on or hardware reset PasswordAttemptCounterExceeded

Password Rules

Security States

Security State Transitions

Security State Transitions

Abusing the Security Feature Set However the current BIOS version of most computers

have no or only partial supports of this new security mode feature, which would be a very severe security hole that is exploitable by a malware to lock the hard disk with password stealthily to prevent any further hard disk access after the next power-off.

In such a circumstance, to prevent the “Security Mode Feature Set” from being abused, a third-party pre-boot software is needed, as the format of either a BIOS extension or a bootable CD, which will issue the ATA command “Security Freeze Lock” to the ATA controller/drive to freeze all security settings until the next cold boot.

Dell D620 HD PW BIOS Configuration

Cracking the Harddisk Lock Password

The harddisk will read the firmware area during the power-on process and determine whether it was locked or not, if locked then any other operation is not allowed before unlocking it with a correct password, since the passwords are stored in the negative tracks of the harddisk (a.k.a, firmware area) other than the drive circuit, it can’t be cracked by simply changing the PCB.

It is said that someone can break this password protection by using the combination of PCB (Print Circuit Board) hot-swap and the supports of some professional harddisk repair tools (MHDD or PC3000 etc).

EFS vs. Windows Vista Bitlocker

EFS Introduction

EFS Cracking

Windows Vista Bitlocker Introduction

TPM Introduction

TPM Security Issues

EFS Introduction EFS: Encrypted File System

Important Keys Used FEK: File Encryption Key (DESX, AES, or 3DES) User’s Public/Private Key Pair (RSA) User’s Master Key (64 bytes) A Key Derived From User’s Password (3DES)

Components Involved EFS & NTFS Driver KSecDD Lsass (Lsasrv) CSP

EFS Architecture

EFS DDF & DRF

EFS Cracking The Basic Concept of EFS Cracking:

User’s Password Derived Key Master Key Private Key FEK File Data Plaintext

Detailed Cracking Steps: Get the user’s password by SAM attacking. (pwdump, L0pht

Crack etc) Compute the derived key based on the user’s password. Decrypt the master key. (%UserProfile%\Application Data\Mic

rosoft\Protect\SID ) Decrypt the private key. (%UserProfile%\Application Data\Mic

rosoft\Crypto\RSA\SID) Decrypt the FEK. Decrypt the file data.

Windows Vista Bitlocker Introduction Bitlocker:

1. Full drive volume encryption.2. Integrity checking of early boot components.

Important Keys/Passwords Used: FVEK: Full Volume Encryption Key VMK: Volume Master Key PIN: Personal Identification Number Clear Key Restore Key/Password Startup Key

System Requirements: TPM v1.21 v1.2 TCG-compliant BIOS USB Mass Storage Device Class supports At least 2 volumes (OS/Boot & System Volume)

Bitlocker Architecture

Encryption Keys In Bitlocker

Bitlocker Drive Encryption-Enabled Volume With TPM Protection

Bitlocker Drive Encryption-Enabled Volume With Enhanced Protection

TPM Introduction TPM: Trusted Platform Module

Protected capabilities Integrity measurement Integrity reporting

TPM Terminologies TBB: Trust Building Block CRTM: Core Root of Trust Measurement (BIOS Bootblock) PCRs: Platform Configuration Registers Extend operation: PCR[n] <-- SHA-1 (PCR[n] + measured da

ta) TPM BIOS Driver (MA/MP)

TPM Architecture

TPM Components Architecture

PCRs Usages Summary

Dell D620 TPM BIOS Configuration

Dell D620 TPM BIOS Configuration

TPM Security Issues Three Conditions That Make the Chain of Hashes Trus

tyworthy:1. The first code running and extending PCRs after a platform r

eset (SRTM) is trustworthy and cannot be replaced.2. The PCRs are not resetable without passing control to truste

d code.3. The chain is contiguous. There is no code in between that is

executed but not hashed.

TPM Security: Bootloader bugs (Violates condition 3) TPM reset (Violates condition 2) BIOS attack (Violates condition 1, CRTM and TPM MP Driver p

atchable) TPMKit? (BlackHat USA 2007)

TPM BIOS MP Driver

TPM BIOS Driver Header

MPTPMTransmit Prototype

Waterbox & Harddisk Protection/Recovery Software

Waterbox Software Introduction

Waterbox Software Bypassing

Harddisk Protection/Recovery Software/Card Introduction

Harddisk Protection/Recovery Software Penetration

Waterbox Software Introduction

What Is A Waterbox Software?Information leakage Prevention, a.k.a. Document Security Management (Pr

otection) System.

Popular Waterbox Softwares FileSECURE (AirZip) FSD/FSF/FSN/Wrapsody (FASOO) FD-DSM (Frontier Technology) CDG (E-SAFENET) InfoGuard (UNNOO) NET-LOCK (Sagetech)

Implementation Technique Categories Peripheral device & network protocol control File & directory encryption File format convertion Remote file storage Information filter Application plugin Kernel mode real-time transparent file encryption/decryption

Waterbox Software Bypassing

The Theory of Real-time Transparent File Encryption/Decryption:The file data are encrypted on disk, and the Waterbox will only decrypt/e

ncrypt the file read/write requests that are issued within some specified process contexts, such as Winword.exe…

Implementation Methods User Mode: File Win32/Native API hooking (Including Memory Mappi

ng functions) Kernel Mode: FS Filter driver

Bypassing Steps:1. Inject a DLL into the process which can make the Waterbox decrypt f

iles. 2. Open and read the desired encrypted files.3. Pass the decrypted file contents to another process via shared mem

ory.4. Write the received file data to disk within that process.

Harddisk Protection/Recovery Software/Card Introduction

What Can A Harddisk Protection/Recovery Software/Card Do?

Any modification made on the protected harddisk will be restored automatically upon the next system boot, many internet bar install this kind of softwares to prevent their PCs from being ruined by customers.

Popular Harddisk Protection/Recovery Softwares DeepFreeze (Faronics) PowerShadow PowerUser/PowerServer Returnil Virtual System (RVS) Sandboxie

Harddisk Protection/Recovery Software Penetration

The Theory of Harddisk Protection/Recovery:The disk access requests made on the protected disk partitions a

re intercepted and redirected to other disk locations, for example a hidden reserved disk partition.

Implementation Methods: DOS time: PCI/ISA Option ROM, intercept BIOS int13h. Windows: Disk Filter driver, attach on DR0 device object.

Penetration Techniques (Used by Machine Dog virus)1. Detach the filter device object that was stacked on DR0. 2. Create a virtual disk volume object.3. Passthrough instruction (DeviceIoControl).4. Direct port I/O.

Thanks For Watching ！Question & Discussion

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