Are invalid/unknown user login attempts via SSH recorded?
Applies to
- ONTAP 9.x
- SSH
- Event Management System (EMS)
Answer
- Invalid/unknown user attempts are logged in EMS :
Message Name:
Severity: NOTICE
Description: This event is issued when sshd refuses a login attempt due to authentication failure.
Corrective Action: Use a valid username/password combination to login.
sshd.auth.loginDeniedSeverity: NOTICE
Description: This event is issued when sshd refuses a login attempt due to authentication failure.
Corrective Action: Use a valid username/password combination to login.
Example:
Thu Aug 4 18:05:09 +0300 [cluster1-01: sshd: sshd.auth.loginDenied:notice]: params: {'message': 'Failed keyboard-interactive / pam for invalid user user123 from 10.x.y.4 port 61582 ssh2 '}Message Name:
Severity: ERROR
Description: This message occurs when a user tries to establish a Secure Shell (SSH) connection to a storage system and does not provide the password within the allotted timeout period. Many such connection attempts could potentially disallow other users from logging in to the storage system, causing a Denial of Service (DOS) attack.
Corrective Action: If the remote host is retrying the SSH connection repeatedly, block the remote host by adding its IP address to the deny list using the "firewall policy" command.
sshd.loginGraceTime.expiredSeverity: ERROR
Description: This message occurs when a user tries to establish a Secure Shell (SSH) connection to a storage system and does not provide the password within the allotted timeout period. Many such connection attempts could potentially disallow other users from logging in to the storage system, causing a Denial of Service (DOS) attack.
Corrective Action: If the remote host is retrying the SSH connection repeatedly, block the remote host by adding its IP address to the deny list using the "firewall policy" command.
Example:
09/23/2020 11:41:51 cluster1-01 ERROR sshd.loginGraceTime.expired: Timeout before password authentication for remote host 10.x.y.7- Additionally, the “illegal user” authentication failures can be found in the Messages.log:
Fri Oct 16 08:18:35 2020 cluster1-01 [auth_sshd:error:45682] error: PAM: authentication error for illegal user test from 10.2.3.4