Cisco ISR 4000 Family Routers Administrator Guidance
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This configures IPsec to use pre-shared keys. X.509 v3 certificates are also
supported for authentication of IPsec peers. See Section 4.6.3 below for additional
information.
TOE-common-criteria(config-isakmp)#
Crypto isakmp key cisco123!cisco123!CISC
address 11.1.1.4
Note:
Pre-shared keys on the TOE must be at least 22 characters in length and can
be composed of any combination of upper and lower case letters, numbers, and
special characters (that include: “!”, “@”, “#”, “$”, “%”, “^”, “&”, “*”, “(“,
and “)”).
The TOE supports pre-shared keys up to 127 characters in length. While longer
keys increase the difficulty of brute-force attacks, longer keys increase processing
time.
TOE-common-criteria (config-isakmp)#
group 14
This selects DH Group 14 (2048-bit MODP) for IKE, but 19 (256-bit Random
ECP), 24 (2048-bit MODP with 256-bit POS), 20 (384-bit Random ECP), 15 (3072
bit MODP), and 16 (4096-bit MODP) are also allowed and supported.
TOE-common-criteria (config-isakmp)#
crypto isakmp aggressive-mode disable
Main mode is the default mode and the
crypto isakmp aggressive-mode disable
ensures all IKEv1 Phase 1 exchanges will be handled in the default main mode.
TOE-common-criteria(config-isakmp)#
exit
4.6.1.2
IKEv2 Transform Sets
An Internet Key Exchange version 2 (IKEv2) proposal is a set of transforms used in the negotiation
of IKEv2 SA as part of the IKE_SA_INIT exchange. An IKEv2 proposal is regarded as complete
only when it has at least an encryption algorithm, an integrity algorithm, and a Diffie-Hellman
(DH) group configured. If no proposal is configured and attached to an IKEv2 policy, then the
default proposal is used in the negotiation, and it contains selections that are not valid for the TOE.
Thus
the following settings must be set in configuring the IPsec with IKEv2 functionality for
the TOE:
TOE-common-criteria #
conf t
TOE-common-criteria (config)#
crypto ikev2 proposal sample
TOE-common-criteria (config-ikev2-proposal)#
integrity sha
Note: md5 is not to be used in the evaluated configuration.
TOE-common-criteria (config-ikev2-proposal)#
encryption aes-cbc-128
This configures IPsec IKEv2 to use AES-CBC-128 for payload encryption. AES-
CBC-256 can be selected with ‘
encryption aes-cbc-256
’. These are the only
allowed ciphers in the evaluated configuration, and the other, less secure ciphers,
are not to be used.