Details
A replay attack may enable an unauthorized user to gain access to the application. Authentication sessions between the authenticator and the application validating the user credentials must not be vulnerable to a replay attack.
An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message.
Solution
Configure SSH to use FIPS-140-2 compliant HMACs as shown in the example below:
SW1(config)#ip ssh version 2
SW1(config)#iip ssh server algorithm encryption aes256-ctr aes192-ctr aes128-ctr
Note: An SSH configuration enables a server and client to authorize the negotiation of only those algorithms that are configured from the allowed list. If a user tries to negotiate using an algorithm that is not part of the allowed list, the request is rejected and the session is not established.
Supportive Information
The following resource is also helpful.
This security hardening control applies to the following category of controls within NIST 800-53: Identification and Authentication.This control applies to the following type of system Cisco.
References
- 800-53|IA-2(8)
- CAT|II
- CCI|CCI-001941
- Rule-ID|SV-220536r508554_rule
- STIG-ID|CISC-ND-000530
- STIG-Legacy|SV-110527
- STIG-Legacy|V-101423
- Vuln-ID|V-220536