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Cisco 2600 Series Multiservice Platforms

Cisco 2621 Security Policy, No. 1112

Product Bulletin, No. 1112

Cisco 2621 Security Policy

Project Headline

This document describes the rules for an IOS system using software-based IPSec encryption when used in accordance with FIPS 140-1 level 2 requirements. Please see [FIPS 140-1] for a full list of the FIPS 140-1 requirements.

Definitions

This section defines words, acronyms, and actions which may not be readily understood.

IPSec - Internet Protocol Security, a family of IETF protocols which provide network layer encryption.

IKE - Internet Key Exchange, a key management protocol used by IPSec for authentication and secret key derivation.

1.0 Roles and Services

Role-based authentication is used by the IOS. Two roles are defined: a User role, and a Crypto-Officer role. There is no maintenance role. Services available for each role are listed. Please see [UNIVERCD -found at the last page underReference Documents] for a detailed configuration description.

1.1 User Role

A user enters the system by accessing the console port with a terminal program.

The IOS prompts the user for their password, entered in plaintext. If it matches the plaintext password stored in IOS memory, the user is allowed entry to the IOS executive program. The non-cryptographic services available to the User role include the following:

  • Obtain non-encryption router status (e.g., state of an interface, state of layer 2 protocols, version of IOS cur-rently running)

  • Connect to other network devices (e.g., outgoing Telnet, PPP)

  • Initiate diagnostic network services (e.g., ping, mtrace)

  • Adjust the terminal session (e.g., lock the terminal, adjust flow control)

  • Display a directory of files kept in Flash memory

  • Other non-cryptographic services can be viewed in the console by typing "?" at the command prompt.

The following cryptographic services are available to the user:

Crypto User Encryption Services

Description of Service Executive Command

Attempt to enter the crypto officer role

Enable



1.2 Crypto-Officer Role

The Crypto-Officer role is entered from the User role by typing the enable command and responding with an appropriate password. The enable password entered by the Crypto-Officer is compared to a password stored in the router memory. If two passwords match, the Crypto-Officer enters the Crypto-Officer role.

The non-cryptographic services available to the Crypto-Officer role include the following:

  • Perform router configuration (e.g., defining IP addresses, enabling interfaces, enabling network services)

  • Reload and shut down the router

  • Display full status of the router

  • Shut down and restart network services

  • Display the router configuration stored in memory, and also the version saved in NVRAM, which is used to initialize a router following a reboot.

  • Other non-cryptographic services can be viewed in the console by typing "?" at the command prompt.

The following cryptographic services are available to the Crypto-Officer:

Crypto-Officer Cryptographic Services: Configuration

Description of Service Configuration Command

Add/delete crypto users, and assign passwords to users

line console 0 (to enable user role and password)

password (enter password)

login

Create the crypto officer password

Enable password

Set IPSec security association parameters

Crypto ipsec security-association

Set an IPSec transform set

Crypto ipsec transform-set

Create access-lists to match encrypted traffic

access-list <100-199>

Define IPSec policy and keys for a connection

crypto map

Set IPSec policy on a network interface

interface <interface name>

crypto map



Executive commands in the User role are also available in the Crypto-Officer role. The following commands are only available to the Crypto-Officer:

Crypto-Officer Cryptographic Services: Executive Commands

Description of Service Executive Command

Show the current IPSec security associations

show crypto ipsec sa

Show the current IPSec security association lifetimes

show crypto ipsec security- association-lifetime

Show the current IPSec transforms

show crypto ipsec transform-set

Show the number of encrypted and decrypted packets on a router

show crypto engine connections active

Clear an IPSec security association

clear crypto sa

Execute encryption self tests

Power regeneration or command "reload" for soft reboot



2.0 Security Rules

2.1 System Requirements

The following requirements relate to how the IOS system must be configured.

1. The tamper-evident labels must be placed according to the "Tamper-evident Label Placements" documentation prior to starting any of the services of the module. There are five tamper-evident labels that must be placed according to the documentation. If any of the labels were tampered with, the labels will clearly indicate that tampering has occurred. The tamper-evident labels have to two layers. Upon tampering, the second layer will be peeled with the word "VOID" appearing on the first layer, which will stay on the module. This will clearly show tamper evidence.

2. The IOS version must be an image of the following type: c2600-ik25-mz, release ___ or later.

3. The IOS version which is shipped with a router is the only allowable image. The loading of any other image is not allowed.

4. The value of the config-register which affects booting must be 0x0101 (the factory default). This setting disables "break" from the console to the ROM monitor, and specifies the first file in Flash to be the boot IOS image.

5. The Crypto-Officer must be present when the system is initialized and perform the initial configuration. The Crypto-Officer must create at least one Crypto-Officer role, as well as define the enable password for the Crypto-Officer role.

6. The Crypto-Officer shall always assign passwords to users.

7. The Crypto-Officer shall only assign users to a privilege level 1 (the default)

8. The Crypto-Officer shall not assign a command to any privilege level other than its default.

9. The following network services affect the security data items and must not be configured: SNMP, NTP, TACACS+, RADIUS, Kerberos.

10. Using RSA will take the module out of FIPS mode under IKE.

11. All terminal services must be disabled, except for the console. The following configuration disables login services on the auxiliary console line:

  line aux 0
  no exec
  To disallow Telnet and x.29 access to the router, the following configuration must be used:
  line vty 0 4
  transport input none

2.2 IPSec Requirements and Cryptographic Algorithms

There are two types of key management methods allowed in FIPS mode:

  • IPSec manually entered keys

  • Internet Key Exchange with Pre-shared keys

Although the IOS implementation of IKE allows a number of algorithms, only the following transforms using FIPS approved algorithms are allowed in a FIPS 140-1 configuration:

  • ah-sha-hmac

  • esp-des

  • esp-sha-hmac

  • esp-3des (approved for government use)

Other non-FIPS approved algorithms include:

  • RSA

  • MD-4

  • MD-5

3.0 Security Data Items

The following sections describe security relevant data items, and any restrictions on the user-configurable data items.

3.1 Passwords

The Crypto-Officer shall set user passwords to be at least 8 characters in length.

  • User Passwords

  • Enable Password

3.2 Keys

  • IPSec DES Session Keys

  • IPSec SHA HMAC Keys

  • IKE Pre-shared Keys

The cryptographic keys are physically protected by the tamper-evident labels. The cryptographic keys are also protected with passwords.

Reference Documents

[FIPS 140-1] FIPS PUB 140-1 FEDERAL INFORMATION PROCESSING STANDARDS PUBLICATION. Available online at http://csrc.ncsl.nist.gov/fips/fips1401.htm

[UNIVERCD] Cisco IOS documentation. Available online at http://www.cisco.com/univercd/cc/td/doc/product/software/index.htm