Table of Contents

Preface ................................................................ xvii


About This Book ........................................................ xvii
Summary of Contents ................................................... xviii
Acknowledgments ......................................................... xix
Comments and Questions ................................................... xx


Part I OVERVIEW ........................................................... 1


Chapter  1  Introduction   ................................................ 3

Attack of the Giant Worm (and Other Tales) ................................ 3
What Is Computer Security? ................................................ 8
    A Broader Definition of Security ...................................... 9
    Secrecy and Confidentiality ........................................... 9
    Accuracy, Integrity, and Authenticity ................................. 9
    Availability ......................................................... 10
Threats to Security ...................................................... 11
    Vulnerabilities ...................................................... 11
    Threats .............................................................. 13
    Countermeasures ...................................................... 16
Why Buy Security? ........................................................ 17
    Government Requirements .............................................. 18
    Information Protection ............................................... 19
What's A User To Do? ..................................................... 20


Chapter  2  Some Security History   ...................................... 23

Information and its Controls ............................................. 24
Computer Security:  Then and Now ......................................... 25
Early Computer Security Efforts .......................................... 27
    Tiger Teams .......................................................... 29
    Research and Modeling ................................................ 30
    Secure Systems Development ........................................... 31
Building Toward Standardization .......................................... 31
    Standards for Secure Systems ......................................... 32
    Standards for Cryptography ........................................... 36
    Standards for Emanations ............................................. 37
Computer Security Mandates and Legislation ............................... 38
    NSDD 145 ............................................................. 39
    NTISSP 2 ............................................................. 39
    Computer Fraud and Abuse Act ......................................... 40
    Computer Security Act ................................................ 41
    Searching for a Balance .............................................. 42
    Recent Government Security Initiatives ............................... 42
Privacy Considerations ................................................... 44
International Security Activity .......................................... 46
The Growth of Modern Standards ........................................... 47


Part II  COMPUTER SECURITY ............................................... 53


Chapter  3  Computer System Security and Access Controls   ............... 55

What Makes a System Secure? .............................................. 55
System Access:  Logging Into Your System ................................. 57
    Identification and Authentication .................................... 57
    Protecting Passwords ................................................. 62
Data Access:  Protecting Your Data ....................................... 66
    Discretionary Access Control ......................................... 67
    Mandatory Access Control ............................................. 72


Chapter  4  Viruses and Other Wildlife   ................................. 79

Viruses .................................................................. 79
Worms .................................................................... 82
Trojan Horses ............................................................ 83
Bombs .................................................................... 84
Trap Doors ............................................................... 85
Spoofs ................................................................... 86
Other Wildlife ........................................................... 86
Remedies ................................................................. 88


Chapter  5  Secure System Planning and Administration .................... 89

Administrative Security .................................................. 89
Overall Planning and Administration ...................................... 91
    Analyzing Costs and Risks ............................................ 91
    Planning for Disaster ................................................ 93
    Setting Security Rules for Employees ................................. 94
    Training Users ....................................................... 94
Day-to-day Administration ................................................ 96
    Performing Backups ................................................... 96
    Performing a Security Audit .......................................... 99
Separation of Duties .................................................... 100


Chapter  6  Inside the Orange Book   .................................... 103

Introduction to the Orange Book ......................................... 104
A Summary of Security Concepts .......................................... 105
    What's a Trusted System? ............................................ 105
    Measuring Trust ..................................................... 106
    Trusted Computing Base .............................................. 107
    Security Policy ..................................................... 108
    Security Model ...................................................... 108
    Security Kernel ..................................................... 109
    Security Perimeter .................................................. 110
Orange Book Evaluation Classes .......................................... 110
    Comparison of Evaluation Classes .................................... 112
    Complaints About the Orange Book .................................... 112
Evaluations of Secure Systems ........................................... 115
Security Policy Requirements ............................................ 115
    Discretionary Access Control ........................................ 116
    Object Reuse ........................................................ 118
    Labels .............................................................. 119
    Mandatory Access Control ............................................ 124
Accountability Requirements ............................................. 124
    Identification and Authentication ................................... 124
    Trusted Path ........................................................ 126
    Audit ............................................................... 128
Assurance Requirements .................................................. 133
    Operational Assurance ............................................... 134
    Life-cycle Assurance ................................................ 141
Documentation Requirements .............................................. 149
    Security Features User's Guide ...................................... 150
    Trusted Facility Manual ............................................. 151
    Test Documentation .................................................. 152
    Design Documentation ................................................ 153
Summary of Classes ...................................................... 155
    D Systems:  Minimal Security ........................................ 155
    C1 Systems:  Discretionary Security Protection ...................... 155
    C2 Systems:  Controlled Access Protection ........................... 156
    B1 Systems:  Labeled Security Protection ............................ 157
    B2 Systems:  Structured Protection .................................. 157
    B3 Systems:  Security Domains ....................................... 158
    A1 Systems:  Verified Design ........................................ 159
Compartmented Mode Workstations ......................................... 159
Government Computer Security Programs ................................... 161


Part III  COMMUNICATIONS SECURITY ....................................... 163


Chapter  7  Encryption   ................................................ 165

Some History ............................................................ 166
What is Encryption? ..................................................... 169
    Why Encryption? ..................................................... 171
    Transposition and Substitution Ciphers .............................. 172
    Cryptographic Keys:  Private and Public ............................. 175
    Key Management and Distribution ..................................... 177
    One-time Pad ........................................................ 178
The Data Encryption Standard ............................................ 179
    What is the DES? .................................................... 182
    Future of the DES ................................................... 185
Other Cryptographic Algorithms .......................................... 188
    Variations on the DES ............................................... 188
    Public Key Algorithms ............................................... 188
    The RSA Algorithm ................................................... 189
    Digital Signatures and Notaries ..................................... 190
    Government Algorithms ............................................... 192
Message Authentication .................................................. 192
Encryption in Banking and Financial Applications ........................ 193
Government Cryptographic Programs ....................................... 196
    NSA ................................................................. 196
    NIST ................................................................ 197
    Treasury ............................................................ 197
Cryptographic Export Restrictions ....................................... 197


Chapter  8  Communications and Network Security   ....................... 201

What Makes Communication Secure? ........................................ 202
    Communications Vulnerabilities ...................................... 204
    Communications Threats .............................................. 204
Modems .................................................................. 205
Networks ................................................................ 207
    Network Terms ....................................................... 207
    Some Network History ................................................ 210
    Network Media ....................................................... 212
OSI Model ............................................................... 215
Network Security ........................................................ 218
    Trusted Networks .................................................... 218
    Perimeters and Gateways ............................................. 221
    Security in Heterogeneous Environments .............................. 221
    Encrypted Communications ............................................ 222
The Red Book and Government Network Evaluations ......................... 226
    TCSEC Requirements .................................................. 228
    Other Security Services ............................................. 228
Some Network Security Projects .......................................... 232
    DISNet and Blacker .................................................. 232
    SDNS ................................................................ 232
    Kerberos ............................................................ 233
    Project MAX ......................................................... 233
    Secure NFS .......................................................... 234


Part IV  OTHER TYPES OF SECURITY ........................................ 235


Chapter  9  Physical Security and Biometrics   .......................... 237

Physical Security ....................................................... 238
    Natural Disasters ................................................... 238
    Risk Analysis and Disaster Planning ................................. 241
Locks and Keys:  Old and New ............................................ 241
    Types of Locks ...................................................... 243
    Tokens .............................................................. 243
    Challenge-response Systems .......................................... 244
    Cards:  Smart and Dumb .............................................. 244
Biometrics .............................................................. 246
    Fingerprints ........................................................ 249
    Handprints .......................................................... 250
    Retina Patterns ..................................................... 250
    Voice Patterns ...................................................... 251
    Signature and Writing Patterns ...................................... 251
    Keystrokes .......................................................... 252


Chapter  10  TEMPEST   .................................................. 253

The Problem of Emanations ............................................... 254
The TEMPEST Program ..................................................... 255
How To Build TEMPEST Products ........................................... 257
TEMPEST Standards and Restrictions ...................................... 259
    TEMPEST Standards ................................................... 259
    TEMPEST Export Restrictions ......................................... 260
Who Cares About TEMPEST? ................................................ 261
    Is TEMPEST Needed? .................................................. 262
    Changing TEMPEST Concepts ........................................... 263
Government TEMPEST Programs ............................................. 265


Part V  APPENDICES ...................................................... 267


Appendix  A  Acronyms   ................................................. 269


Appendix  B  Computer Security Legislation   ............................ 277


Appendix  C  Orange Book and Other Summaries   .......................... 289

Orange Book (TCSEC) Requirements ........................................ 289
Compartmented Mode Workstation (CMW) Requirements ....................... 313
System High Workstation (SHW) Requirements .............................. 315
International Security (ITSEC) Requirements ............................. 318


Appendix  D  Government Security Programs   ............................. 323

Computer Security Programs .............................................. 323
    The Role of the NCSC ................................................ 324
    The Role of NIST .................................................... 325
    Trusted Product Evaluation Program (TPEP) ........................... 326
    Evaluation of Network Products ...................................... 331
    Evaluations of Database Management Systems .......................... 332
    Evaluations of Security Subsystem Products .......................... 333
    Formal Verification Systems Evaluation Program (FVSEP) .............. 336
    Degausser Products List ............................................. 338
    Rating Maintenance Phase (RAMP) Program ............................. 338
    System Certification and Accreditation .............................. 339
    DOCKMASTER .......................................................... 340
    Technical Vulnerability Reporting Program ........................... 341
Communications Security Programs ........................................ 341
    Commercial COMSEC Endorsement Program ............................... 342
    CCEP Eligibility .................................................... 343
    CCEP Program Steps .................................................. 344
    Government Endorsed DES Equipment Program ........................... 345
    EFT Certification Program ........................................... 346
    Protected Network Services List ..................................... 346
    Off-line Systems List (OLSL) ........................................ 347
    Restrictions on Cryptographic Products .............................. 347
TEMPEST Security Programs ............................................... 348
    Industrial TEMPEST Program and Preferred Products List .............. 349
    Endorsed TEMPEST Products Program ................................... 351
    Endorsed TEMPEST Test Services Program .............................. 356
    Endorsed TEMPEST Test Instrumentation Program ....................... 357


Appendix  E  A Security Source Book   ................................... 359

Government Publications ................................................. 360
    The Rainbow Series .................................................. 360
    Other NSA Publications .............................................. 369
    FIPS PUBs ........................................................... 370
    NIST Special Publications ........................................... 374
    Other NIST Publications ............................................. 385
    Compartmented Mode Workstation (CMW) Publications ................... 385
    COMSEC Program Publications ......................................... 386
    TEMPEST Program Publications ........................................ 386
    Other Security-relevant Government Publications ..................... 387
Government Program Contact Points ....................................... 387
    Computer Security (COMPUSEC) Programs ............................... 388
    Communications Security (COMSEC) Programs ........................... 389
    TEMPEST Programs .................................................... 390
    Other Government Contacts ........................................... 390
Emergency Organizations ................................................. 391
Standards Organizations ................................................. 391
Security User Groups .................................................... 393
Electronic Groups ....................................................... 397
    USENET .............................................................. 397
    Commercial Bulletin Boards .......................................... 397
    NCSC DOCKMASTER ..................................................... 398
    NIST Computer Security Bulletin Board ............................... 398
Computer Security Periodicals ........................................... 399
Computer Security Books ................................................. 401
    Conference Proceedings .............................................. 401
    Computer Security Textbooks ......................................... 401
    Viruses and Other Programmed Threats ................................ 402
    Computer Crime and Ethics ........................................... 402
    Of General Interest ................................................. 403


Glossary ................................................................ 405


Index ................................................................... 429


                                   Figures

                                                                         Page
3-1   Self/Group/Public Controls ......................................... 69
3-2   Discretionary Access Control With an Access Control List ........... 71
3-3   Mandatory Access Control ........................................... 75
6-1   Comparison of Evaluation Classes .................................. 113
6-2   Example of Labeling on Banner Page ................................ 122
6-3   Sample Trusted Path Menu .......................................... 128
6-4   Sample Audit Output ............................................... 130
7-1   The Enigma Machine* ............................................... 168
7-2   Simple Encryption and Decryption .................................. 171
7-3   A Simple Transposition Cipher ..................................... 172
7-4   Simple Substitution Ciphers ....................................... 173
7-5   Another Transposition Cipher ...................................... 174
7-6   The Caesar Substitution Cipher .................................... 174
7-7   A Simple Example of Private Key Encryption/Decryption ............. 176
7-8   A Simple Example of Public Key Encryption/Decryption .............. 177
7-9   A One-time Pad .................................................... 179
7-10   How the DES Works ................................................ 183
8-1   Open Systems Interconnection (OSI) Model .......................... 215
8-2   End-to-end Encryption ............................................. 223
8-3   Link Encryption ................................................... 225


                                   Tables

                                                                         Page
2-1   Security-relevant Standards Organizations .......................... 48
3-1   Sample Login/Password Controls ..................................... 63
6-1   Evaluation Classes and Sample Systems ............................. 111
6-2   Discretionary Access Control (DAC) Requirements ................... 117
6-3   Identification and Authentication (I&A) Requirements .............. 126
6-4   Audit Requirements ................................................ 132
6-5   System Architecture Requirements .................................. 135
6-6   Covert Channel Requirements ....................................... 138
6-7   Trusted Facility Management Requirements .......................... 140
6-8   Security Testing Requirements ..................................... 142
6-9   Design Specification and Verification Requirements ................ 144
6-10   Configuration Management Requirements ............................ 146
6-11   Trusted Facility Manual (TFM) Requirements ....................... 151
6-12   Test Documentation Requirements .................................. 152
6-13   Design Documentation Requirements ................................ 154
8-1   OSI Model Layers and Functions .................................... 216
8-2   Communications Integrity Requirements ............................. 229
8-3   Denial of Service Requirements .................................... 230
8-4   Compromise Protection Requirements ................................ 231
B-1   Information Protection Legislation ................................ 278
B-2   Computer Crime Legislation ........................................ 284
B-3   Privacy Legislation ............................................... 286
C-5   Compartmented Mode Workstation Requirements ....................... 313
C-6   System High Workstation (SHW) Requirements ........................ 316
C-7   Information Technology Security Evaluation Criteria (ITSEC) ....... 319
C-8   ITSEC Classes of Functionality .................................... 320
C-9   ITSEC Assurance Levels ............................................ 321
E-1   Rainbow Series .................................................... 361
E-2   FIPS PUBs ......................................................... 370
E-3   SPEC PUBs ......................................................... 375