Among the slew of security enhancements introduced in OneFS 9.5 is the ability to mandate a more stringent password policy. This is required to comply with security requirements such as the U.S. military STIG, which stipulates:

The OneFS password security architecture can be summarized as follows:

Within the OneFS security subsystem, authentication is handled in OneFS by LSASSD, the daemon used to service authentication requests for lwiod.

In OneFS AIMA, there are several different kinds of backend providers: Local provider, file provider, AD provider, NIS provider, and so on. Each provider is responsible for the management of users and groups inside the provider. For OneFS password policy enforcement, the local and file providers are the focus.

The local provider is based on an SamDB style file stored with prefix path of /ifs/.ifsvar, and its provider settings can be viewed by the following CLI syntax: 

# isi auth local view System 

On the other hand, the file provider is based on the FreeBSD spwd.db file, and its configuration can be viewed by the following CLI command: 

# isi auth file view System

Each provider stores and manage its own users. For the local provider, isi auth users create CLI command will create a user inside the provider by default. However, for the file provider, there is no corresponding command. Instead, the OneFS pw CLI command can be used to create a new file provider user.

After the user is created, the isi auth users modify <USER> CLI command can be used to change the attributes of the user for both the file and local providers. However, not all attributes are supported for both providers. For example, the file provider does not support password expiry.

The fundamental password policy CLI changes introduced in OneFS 9.5 are as follows:

A user’s password can now be set, changed, and reset by either root or admin. This is supported by the new isi auth users change-password or isi auth users reset-password CLI command syntax. The latter, for example, returns a temporary password and requires the user to change it on next login. After logging in with the temporary (albeit secure) password, OneFS immediately forces the user to change it:

# whoami
admin
# isi auth users reset-password user1
4$_x\d\Q6V9E:sH
# ssh user1@localhost
(user1@localhost) Password:
(user1@localhost) Your password has expired.
You are required to immediately change your password.
Changing password for user1
New password:
(user1@localhost) Re-enter password:
Last login: Wed May 17 08:02:47 from 127.0.0.1
PowerScale OneFS 9.5.0.0
# whoami
user1

Also in OneFS 9.5 and later, the CLI isi auth local view system command sees the addition of four new fields:

• Password Chars Changed
• Password Percent Changed
• Password Hash Type
• Max Inactivity Days

For example:

# isi auth local view system
                    Name: System
                  Status: active
          Authentication: Yes
    Create Home Directory: Yes
 Home Directory Template: /ifs/home/%U
        Lockout Duration: Now
       Lockout Threshold: 0
          Lockout Window: Now
             Login Shell: /bin/zsh
            Machine Name:
        Min Password Age: Now
        Max Password Age: 4W
      Min Password Length: 0
     Password Prompt Time: 2W
      Password Complexity: -
 Password History Length: 0
   Password Chars Changed: 0
Password Percent Changed: 0
      Password Hash Type: NTHash
      Max Inactivity Days: 0

The following CLI command syntax configures OneFS to require a minimum password length of 15 characters, a 50% or greater change, and 8 or more characters to be altered for a successful password reset:

# isi auth local modify system --min-password-length 15 --password-chars-changed 8 --password-percent-changed 50

Next, a command is issued to create a new user, user2, with a 10-character password:

# isi auth users create user2 --password 0123456789
Failed to add user user1: The specified password does not meet the configured password complexity or history requirements

This attempt fails because the password does not meet the configured password criteria (15 chars, 50% change, 8 chars to be altered).

Instead, the password for the new account, user2, is set to an appropriate value: 0123456789abcdef. Also, the --prompt-password-change flag is used to force the user to change their password on next login.

# isi auth users create user2 --password 0123456789abcdef –prompt-password-change 1

When the user logs in to the user2 account, OneFS immediately prompts for a new password. In the following example, a non-compliant password (012345678zyxw) is entered. 

0123456789abcdef -> 012345678zyxw = Failure

This returns an unsuccessful change attempt failure because it does not meet the 15-character minimum:

# su user2
New password:
Re-enter password:
The specified password does not meet the configured password complexity requirements.
Your password must meet the following requirements:
  * Must contain at least 15 characters.
  * Must change at least 8 characters.
  * Must change at least 50% of characters.
New password:

Instead, a compliant password and successful change could be: 

0123456789abcdef -> 0123456zyxwvuts = Success

The following command can also be used to change the password for a user. For example, to update user2’s password:

# isi auth users change-password user2
Current password (hit enter if none):
New password:
Confirm new password:

If a non-compliant password is entered, the following error is returned:

Password change failed: The specified password does not meet the configured password complexity or history requirements

When employed, OneFS hardening automatically enforces security-based configurations. The hardening engine is profile-based, and its STIG security profile is predicated on security mandates specified in the U.S. Department of Defense (DoD) Security Requirements Guides (SRGs) and Security Technical Implementation Guides (STIGs).

On applying the STIG hardening security profile to a cluster (isi hardening apply --profile=STIG), the password policy settings are automatically reconfigured to the following values:

For example:

# uname -or
Isilon OneFS 9.5.0.0
 
# isi hardening list
Name  Description                       Status
---------------------------------------------------
STIG  Enable all STIG security settings Applied
---------------------------------------------------
Total: 1
 
# isi auth local view system
                    Name: System
                  Status: active
          Authentication: Yes
   Create Home Directory: Yes
 Home Directory Template: /ifs/home/%U
        Lockout Duration: Now
       Lockout Threshold: 3
          Lockout Window: 15m
             Login Shell: /bin/zsh
             Machine Name:
        Min Password Age: 1D
        Max Password Age: 8W4D
     Min Password Length: 15
    Password Prompt Time: 2W
     Password Complexity: lowercase, numeric, repeat, symbol, uppercase
 Password History Length: 5
  Password Chars Changed: 8
Password Percent Changed: 50
      Password Hash Type: SHA512
     Max Inactivity Days: 35

Note that Password Hash Type is changed from the default NTHash to the more secure SHA512 encoding, in addition to setting the various password criteria.

The OneFS 9.5 WebUI also sees several additions and alterations to the Password policy page. These include:

The most obvious change is the transfer of the policy configuration elements from the local provider page to a new dedicated Password policy page.

Here’s the OneFS 9.4 View a local provider page, under Access > Authentication providers > Local providers > System:

This is replaced and augmented in the OneFS 9.5 WebUI with the following page, located under Access > Membership and roles > Password policy:

New password policy configuration options are included to require uppercase, lowercase, numeric, or special characters and limit the number of contiguous repeats of a character, and so on.

When it comes to changing a password, only a permitted user can make their change. This can be performed from a couple of locations in the WebUI. First, the user options on the task bar at the top of each screen now provides a Change password option:

A pop-up warning message will also be displayed by the WebUI, informing the user when password expiration is imminent. This warning provides a Change Password link:

Clicking on the Change Password link displays the following page:

A new password complexity tool-tip message is also displayed, informing the user of safe password selection.

Note that re-login is required after a password change.

On the Users page under Access > Membership and roles > Users, the Action drop-down list on the now also contains a Reset Password option:

The successful reset confirmation pop-up offers both a show and copy option, while informing the cluster administrator to share the new password with the user, and for them to change their password during their next login:  

The Create user page now provides an additional field that requires password confirmation. Additionally, the password complexity tool-tip message is also displayed:

The redesigned Edit user details page no longer provides a field to edit the password directly:

Instead, the Action drop-down list on the Users page now contains a Reset Password option. 

Author: Nick Trimbee

Another of the core security enhancements introduced in OneFS 9.5 is the ability to enforce strict user account security policies. This is required for compliance with both private and public sector security mandates. For example, the account policy restriction requirements expressed within the U.S. military STIG requirements stipulate:

 To directly address these security edicts, OneFS 9.5 adds the following account policy restriction controls:

Architecture

OneFS provides a variety of access mechanisms for administering a cluster. These include SSH, serial console, WebUI, and platform API, all of which use different underlying access methods. The serial console and SSH are standard FreeBSD third-party applications and are accounted for per node, whereas the WebUI and pAPI use HTTP module extensions to facilitate access to the system and services and are accounted for cluster-wide. Before OneFS 9.5, there was no common mechanism to represent or account for sessions across these disparate applications.

Under the hood, the OneFS account security policy framework encompasses the following high-level architecture: 

With SSH, there’s no explicit or reliable “log-off” event sent to OneFS, beyond actually disconnecting the connection. As such, accounting for active sessions can be problematic and unreliable, especially when connections time out or unexpectedly disconnect. However, OneFS does include an accounting database that stores records of system activities like user login and logout, which can be queried to determine active SSH sessions. Each active SSH connection has an isi_ssh_d process owned by the account associated with it, and this information can be gathered via standard syscalls. OneFS enumerates the number of SSHD processes per account to calculate the total number of active established sessions. This value is then used as part of the total concurrent administrative sessions limit. Since SSH only supports user access through the system zone, there is no need for any zone-aware accounting.

The WebUI and platform API use JSON web tokens (JWTs) for authenticated sessions. OneFS stores the JWTs in the cluster-wide kvstore, and access policy uses valid session tokens in the kvstore to account for active sessions when a user logs on through the WebUI or pAPI. When the user logs off, the associated token is removed, and a message is sent to JWT service with an explicit log off notification. If a session times out or disconnects, the JWT service will not get an event, but the tokens have a limited, short lifespan, and any expired tokens are purged from the list on a scheduled basis in conjunction with the JWT timer. OneFS enumerates the unique session IDs associated with each user’s JWT tokens in the kvstore to get a number of active WebUI and pAPI sessions to use as part of user’s session limit check.

For serial console access accounting, the process table will have information when an STTY connection is active, and OneFS extrapolates user data from it to determine the session count, similar to ssh with a syscall for process data. There is an accounting database that stores records of system activities like user login and logout, which is also queried for active console sessions. Serial console access is only from the system zone, so there is no need for zone-aware accounting.

An API call retrieves user session data from the process table and kvstore to calculate number of user active sessions. As such, the checking and enforcement of session limits is performed in similar manner to the verification of user privileges for SSH, serial console, or WebUI access.

Delaying failed login reconnections

OneFS 9.5 provides the ability to enforce a configurable delay period. This delay is specified in seconds, after which every unsuccessful authentication attempt results in the user being denied the ability to reconnect to the cluster until after the configured delay period has passed. The login delay period is defined in seconds through the FailedLoginDelayTime global attribute and, by default, OneFS is configured for no delay through a FailedLoginDelayTime value of 0. When a cluster is placed into hardened mode with the STIG policy enacted, the delay value is automatically set to 4 seconds. Note that the delay happens in the lsass client, so that the authentication service is not affected.

The configured failed login delay time limit can be viewed with following CLI command:

# isi auth settings global view
                            Send NTLMv2: No
                      Space Replacement:
                              Workgroup: WORKGROUP
               Provider Hostname Lookup: disabled
                          Alloc Retries: 5
                 User Object Cache Size: 47.68M
                       On Disk Identity: native
                         RPC Block Time: Now
                       RPC Max Requests: 64
                            RPC Timeout: 30s
Default LDAP TLS Revocation Check Level: none
                   System GID Threshold: 80
                   System UID Threshold: 80
                         Min Mapped Rid: 2147483648
                              Group UID: 4294967292
                               Null GID: 4294967293
                               Null UID: 4294967293
                            Unknown GID: 4294967294
                            Unknown UID: 4294967294
                Failed Login Delay Time: Now
               Concurrent Session Limit: 0

Similarly, the following syntax will configure the failed login delay time to a value of 4 seconds:

# isi auth settings global modify --failed-login-delay-time 4s
# isi auth settings global view | grep -i delay
                Failed Login Delay Time: 4s

However, when a cluster is put into STIG hardening mode, the “Concurrent sessions limit” is automatically set to 10.

# isi auth settings global view | grep -i delay
                Failed Login Delay Time: 10s

The delay time after login failure can also be configured from the WebUI under Access > Settings > Global provider settings:

The valid range of the FailedLoginDelayTime global attribute is from 0 to 65535, and the delay time is limited to the same cluster node.

Note that this maximum session limit is only applicable to administrative logins.

Disabling inactive accounts

In OneFS 9.5, any user account that has been inactive for a configurable duration can be automatically disabled. Administrative intervention is required to re-enable a deactivated user account. The last activity time of a user is determined by their previous logon, and a timer runs every midnight during which all “inactive” accounts are disabled. If the last logon record for a user is unavailable, or stale, the timestamp when the account was enabled is taken as their last activity instead. If inactivity tracking is enabled after the last logon (or enabled) time of a user, the inactivity tracking time is considered for inactivity period.

This feature is disabled by default in OneFS, and all users are exempted from inactivity tracking until configured otherwise. However, individual accounts can be exempted from this behavior, and this can be configured through the user-specific DisableWhenInactive attribute. For example:

# isi auth user view user1 | grep -i inactive
   Disable When Inactive: Yes
# isi auth user modify user1 --disable-when-inactive 0
# isi auth user view user1 | grep -i inactive
   Disable When Inactive: No

If a cluster is put into STIG hardened mode, the value for the MaxInactivityDays parameter is automatically reconfigured to 35, meaning a user will be disabled after 35 days of inactivity. All the local users are removed from exemption when in STIG hardened mode.

Note that this functionality is limited to only the local provider and does not apply to file providers.

The inactive account disabling configuration can be viewed from the CLI with the following syntax. In this example, the MaxInactivityDays attribute is configured for 35 days:

# isi auth local view system
                    Name: System
                  Status: active
          Authentication: Yes
   Create Home Directory: Yes
 Home Directory Template: /ifs/home/%U
        Lockout Duration: Now
       Lockout Threshold: 0
          Lockout Window: Now
             Login Shell: /bin/zsh
            Machine Name:
        Min Password Age: Now
        Max Password Age: 4W
     Min Password Length: 15
    Password Prompt Time: 2W
     Password Complexity: -
 Password History Length: 0
  Password Chars Changed: 8
Password Percent Changed: 50
      Password Hash Type: NTHash
     Max Inactivity Days: 35

Inactive account disabling can also be configured from the WebUI under Access > Authentication providers > Local provider:

The valid range of the MaxInactivityDays parameter is from 0 to UINT_MAX. As such, the following CLI syntax will configure the maximum number of days a user account can be inactive before it will be disabled to 10 days:

# isi auth local modify system --max-inactivity-days 10
# isi auth local view system | grep -i inactiv
     Max Inactivity Days: 0tem –max-inactivity-days 10

Setting this value to 0 days will disable the feature:

# isi auth local modify system --max-inactivity-days 0
# isi auth local view system | grep -i inactiv
     Max Inactivity Days: 0tem –max-inactivity-days 0

Inactivity account disabling, as well as password expiry, can also be configured granularly, per user account. For example, user1 has a default configuration of the Disable When Inactive threshold set to No.

# isi auth users view user1
                    Name: user1
                      DN: CN=user1,CN=Users,DC=GLADOS
              DNS Domain: -
                  Domain: GLADOS
                Provider: lsa-local-provider:System
        Sam Account Name: user1
                     UID: 2000
                     SID: S-1-5-21-1839173366-2940572996-2365153926-1000
                 Enabled: Yes
                 Expired: No
                  Expiry: -
                  Locked: No
                   Email: -
                   GECOS: -
           Generated GID: No
           Generated UID: No
           Generated UPN: Yes
           Primary Group
                          ID: GID:1800
                        Name: Isilon Users
          Home Directory: /ifs/home/user1
        Max Password Age: 4W
        Password Expired: No
         Password Expiry: 2023-06-15T17:45:55
       Password Last Set: 2023-05-18T17:45:55
        Password Expired: No
              Last Logon: -
                   Shell: /bin/zsh
                     UPN: user1@GLADOS
User Can Change Password: Yes
   Disable When Inactive: No

The following CLI command will activate the account inactivity disabling setting and enable password expiry for the user1 account:

# isi auth users modify user1 --disable-when-inactive Yes --password-expires Yes 

Inactive account disabling can also be configured from the WebUI under Access > Membership and roles > Users > Providers:

Limiting concurrent sessions

OneFS 9.5 can limit the number of administrative sessions active on a OneFS cluster node, and all WebUI, SSH, pAPI, and serial console sessions are accounted for when calculating the session limit. The SSH and console session count is node-local, whereas WebUI and pAPI sessions are tracked cluster-wide. As such, the formula used to calculate a node’s total active sessions is as follows:

Total active user sessions on a node = Total WebUI and pAPI sessions across the cluster + Total SSH and Console sessions on the node

This feature leverages the cluster-wide session management through JWT for calculating the total number of sessions on a cluster’s node. By default, OneFS 9.5 has no configured limit, and the Concurrent Session Limit parameter has a value of 0. For example:

# isi auth settings global view
                            Send NTLMv2: No
                      Space Replacement:
                              Workgroup: WORKGROUP
               Provider Hostname Lookup: disabled
                          Alloc Retries: 5
                 User Object Cache Size: 47.68M
                       On Disk Identity: native
                         RPC Block Time: Now
                       RPC Max Requests: 64
                            RPC Timeout: 30s
Default LDAP TLS Revocation Check Level: none
                   System GID Threshold: 80
                   System UID Threshold: 80
                         Min Mapped Rid: 2147483648
                              Group UID: 4294967292
                               Null GID: 4294967293
                               Null UID: 4294967293
                            Unknown GID: 4294967294
                            Unknown UID: 4294967294
                Failed Login Delay Time: Now
               Concurrent Session Limit: 0

The following CLI syntax will configure Concurrent Session Limit to a value of 5:

# isi auth settings global modify –-concurrent-session-limit 5
# isi auth settings global view | grep -i concur
                Concurrent Session Limit: 5

Once the session limit has been exceeded, attempts to connect, in this case as root through SSH, will be met with the following Access denied error message:

login as: root
Keyboard-interactive authentication prompts from server:
| Password:
End of keyboard-interactive prompts from server                      
Access denied
password:

The concurrent sessions limit can also be configured from the WebUI under Access > Settings > Global provider settings:

However, when a cluster is put into STIG hardening mode, the concurrent session limit is automatically set to a maximum of 10 sessions.

Note that this maximum session limit is only applicable to administrative logins.

Performance

Disabling an account after a period of inactivity in OneFS requires a SQLite database update every time a user has successfully logged on to the OneFS cluster. After a successful logon, the time to logon is recorded in the database, which is later used to compute the inactivity period.

Inactivity tracking is disabled by default in OneFS 9.5, but can be easily enabled by configuring the MaxInactivityDays attribute to a non-zero value. In cases where inactivity tracking is enabled and many users are not exempt from inactivity tracking, a significant number of logons within a short period of time can generate significant SQLite database requests. However, OneFS consolidates multiple database updates during user logon to a single commit to minimize the overall load.

Troubleshooting

When it comes to troubleshooting OneFS account security policy configurations, there are these main logfiles to check:

• /var/log/lsassd.log
• /var/log/messages
• /var/log/isi_papi_d.log

For additional reporting detail, debug level logging can be enabled on the lsassd.log file with the following CLI command:

# /usr/likewise/bin/lwsm set-log-level lsass – debug

When finished, logging can be returned to the regular error level:

# /us/likewise/bin/lwsm set-log-level lsass - error

Author: Nick Trimbee