The Juniper router must be configured to implement replay-resistant authentication mechanisms for network access to privileged accounts.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-217322	SRG-APP-000156-NDM-000250	JUNI-ND-000530	SV-217322r960993_rule	2024-12-05	3

Description
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. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators.

Description

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. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators.

ℹ️ Check
Review the router configuration to verify that SSH is configured to use FIPS-140-2 compliant HMACs as shown in the example below. system { … … … services { ssh { protocol-version v2; macs [hmac-sha2-256 hmac-sha2-512]; } 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 remote party tries to negotiate using an algorithm that is not part of the allowed list, the request is rejected and the session is not established. If the router is not configured to implement replay-resistant authentication mechanisms for network access to privileged accounts, this is a finding.

ℹ️ Check

Review the router configuration to verify that SSH is configured to use FIPS-140-2 compliant HMACs as shown in the example below. system { … … … services { ssh { protocol-version v2; macs [hmac-sha2-256 hmac-sha2-512]; } 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 remote party tries to negotiate using an algorithm that is not part of the allowed list, the request is rejected and the session is not established. If the router is not configured to implement replay-resistant authentication mechanisms for network access to privileged accounts, this is a finding.

✔️ Fix
Configure SSH to use FIPS-140-2 compliant HMACs as shown in the example below. [edit system services] set ssh protocol-version v2 set ssh macs [hmac-sha2-256 hmac-sha2-512] 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.

✔️ Fix

Configure SSH to use FIPS-140-2 compliant HMACs as shown in the example below. [edit system services] set ssh protocol-version v2 set ssh macs [hmac-sha2-256 hmac-sha2-512] 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.