tripleo-docs/deploy-guide/source/features/security_hardening.rst

Security Hardening

TripleO can deploy Overcloud nodes with various Security Hardening values passed in as environment files to the openstack overcloud deploy command.

Note

It is especially important to remember that you must include all environment files needed to deploy the overcloud. Make sure you pass the full environment in addition to your customization environments at the end of each of the openstack overcloud deploy command.

Horizon Password Validation

Horizon provides a password validation check which OpenStack cloud operators can use to enforce password complexity.

Regular expression can be used for password validation with help text to display if the users password does not adhere with validation checks.

The following example will enforce users to create a password between 8 and 18 characters in length:

parameter_defaults:
  HorizonPasswordValidator: '^.{8,18}$'
  HorizonPasswordValidatorHelp: 'Password must be between 8 and 18 characters.'

If the above yaml was saved as horizon_password.yaml we can then pass this into the overcloud deploy command as follows:

openstack overcloud deploy --templates \
  -e <full environment> -e  horizon_password.yaml

Default Security Values in Horizon

The following config directives are set to True as a secure default, however if a reason exists for an operator to disable one of the following values, they can do so using an environment file.

Note

The following directives should only be set to False once the potential security impacts are fully understood.

Enforce Password Check

By setting ENFORCE_PASSWORD_CHECK to True within Horizon's local_settings.py, it displays an ‘Admin Password’ field on the “Change Password” form to verify that it is the admin loggedin that wants to perform the password change.

If a need is present to disable ENFORCE_PASSWORD_CHECK then this can be achieved using an environment file contain the following parameter:

parameter_defaults:
  ControllerExtraConfig:
    horizon::enforce_password_check: false

Disallow Iframe Embed

DISALLOW_IFRAME_EMBED can be used to prevent Horizon from being embedded within an iframe. Legacy browsers are still vulnerable to a Cross-Frame Scripting (XFS) vulnerability, so this option allows extra security hardening where iframes are not used in deployment.

If however a reason exists to allow Iframe embedding, then the following parameter can be set within an environment file:

parameter_defaults:
  ControllerExtraConfig:
    horizon::disallow_iframe_embed: false

Disable Password Reveal

In the same way as ENFORCE_PASSWORD_CHECK and DISALLOW_IFRAME_EMBED the DISABLE_PASSWORD_REVEAL value to be toggled as a parameter:

parameter_defaults:
  ControllerExtraConfig:
    horizon::disable_password_reveal: false

SSH Banner Text

SSH /etc/issue Banner text can be set using the following parameters in an environment file:

resource_registry:
  OS::TripleO::Services::Sshd: ../deployment/sshd/sshd-baremetal-puppet.yaml

parameter_defaults:
  BannerText: |
    ******************************************************************
    * This system is for the use of authorized users only. Usage of  *
    * this system may be monitored and recorded by system personnel. *
    * Anyone using this system expressly consents to such monitoring *
    * and is advised that if such monitoring reveals possible        *
    * evidence of criminal activity, system personnel may provide    *
    * the evidence from such monitoring to law enforcement officials.*
    ******************************************************************

As with the previous Horizon Password Validation example, saving the above into a yaml file, will allow passing the aforementioned parameters into the overcloud deploy command:

openstack overcloud deploy --templates \
  -e <full environment> -e  ssh_banner.yaml

Audit

Having a system capable of recording all audit events is key for troubleshooting and peforming analysis of events that led to a certain outcome. The audit system is capable of logging many events such as someone changing the system time, changes to Mandatory / Discretionary Access Control, creating / destroying users or groups.

Rules can be declared using an environment file and injected into /etc/audit/audit.rules:

parameter_defaults:
  AuditdRules:
    'Record Events that Modify User/Group Information':
      content: '-w /etc/group -p wa -k audit_rules_usergroup_modification'
      order  : 1
    'Collects System Administrator Actions':
      content: '-w /etc/sudoers -p wa -k actions'
      order  : 2
    'Record Events that Modify the Systems Mandatory Access Controls':
      content: '-w /etc/selinux/ -p wa -k MAC-policy'
      order  : 3

Firewall Management

Iptables rules are automatically deployed on overcloud nodes to open only the ports which are needed to get OpenStack working. Rules can be added during the deployment when needed. For example, for Zabbix monitoring system.

parameter_defaults:
  ExtraFirewallRules:
    '301 allow zabbix':
      dport: 10050
      proto: tcp
      source: 10.0.0.8
      action: accept

Rules can also be used to restrict access. The number used at definition of a rule will determine where the iptables rule will be inserted. For example, rabbitmq rule number is 109 by default. If you want to restrain it, you could do.

parameter_defaults:
  ExtraFirewallRules:
    '098 allow rabbit from internalapi network':
      dport:
      - 4369
      - 5672
      - 25672
      proto: tcp
      source: 10.0.0.0/24
      action: accept
    '099 drop other rabbit access':
      dport:
      - 4369
      - 5672
      - 25672
      proto: tcp
      action: drop

In this example, 098 and 099 are arbitrarily numbers that are smaller than the default rabbitmq rule number. To know the number of a rule, inspect the active iptables rules on an appropriate node (controller, in case of rabbitmq)

iptables-save
[...]
-A INPUT -p tcp -m multiport --dports 4369,5672,25672 -m comment --comment "109 rabbitmq" -m state --state NEW -j ACCEPT

Alternatively it's possible to get the information in tripleo service in the definition. In our case in deployment/rabbitmq/rabbitmq-container-puppet.yaml.

firewall_rules:
  '109 rabbitmq':
    dport:
      - 4369
      - 5672
      - 25672
      - 25673-25683

Additional information regarding the the available interface options, the role, some of the implementation details can be reviewed here.

AIDE - Intrusion Detection

AIDE (Advanced Intrusion Detection Environment) is a file and directory integrity checker. It is used as medium to reveal possible unauthorized file tampering / changes.

AIDE creates an integrity database of file hashes, which can then be used as a comparison point to verify the integrity of the files and directories.

The TripleO AIDE service allows an operator to populate entries into an AIDE configuration, which is then used by the AIDE service to create an integrity database. This can be achieved using an environment file with the following example structure:

resource_registry:
  OS::TripleO::Services::Aide: ../puppet/services/aide.yaml

parameter_defaults:
  AideRules:
    'TripleORules':
      content: 'TripleORules = p+sha256'
      order  : 1
    'etc':
      content: '/etc/ TripleORules'
      order  : 2
    'boot':
      content: '/boot/ TripleORules'
      order  : 3
    'sbin':
      content: '/sbin/ TripleORules'
      order  : 4
    'var':
      content: '/var/ TripleORules'
      order  : 5
    'not var/log':
      content: '!/var/log.*'
      order  : 6
    'not var/spool':
      content: '!/var/spool.*'
      order  : 7
    'not /var/adm/utmp':
      content: '!/var/adm/utmp$'
      order: 8
    'not nova instances':
      content: '!/var/lib/nova/instances.*'
      order: 9

Note

Operators should select their own required AIDE values, as the example list above is not activley maintained or benchmarked. It only seeks to provide an document the YAML structure required.

If above environment file were saved as aide.yaml it could then be passed to the overcloud deploy command as follows:

openstack overcloud deploy --templates -e /path/to/aide.yaml

Let's walk through the different values used here.

First an 'alias' name TripleORules is declared to save us repeatedly typing out the same attributes each time. To the alias we apply attributes of p+sha256. In AIDE terms this reads as monitor all file permissions p with an integrity checksum of sha256. For a complete list of attributes that can be used in AIDE's config files, refer to the AIDE MAN page.

Complex rules can be created using this format, such as the following:

MyAlias = p+i+n+u+g+s+b+m+c+sha512

The above would translate as monitor permissions, inodes, number of links, user, group, size, block count, mtime, ctime, using sha256 for checksum generation.

Note, the alias should always have an order position of 1, which means that it is positioned at the top of the AIDE rules and is applied recursively to all values below.

Following after the alias are the directories to monitor. Note that regular expressions can be used. For example we set monitoring for the var directory, but overwrite with a not clause using ! with '!/var/log.*' and '!/var/spool.*'.

Further AIDE values

The following AIDE values can also be set.

`AideConfPath`: The full POSIX path to the aide configuration file, this defaults to /etc/aide.conf. If no requirement is in place to change the file location, it is recommended to stick with the default path.

`AideDBPath`: The full POSIX path to the AIDE integrity database. This value is configurable to allow operators to declare their own full path, as often AIDE database files are stored off node perhaps on a read only file mount.

`AideDBTempPath`: The full POSIX path to the AIDE integrity temporary database. This temporary files is created when AIDE initializes a new database.

'AideHour': This value is to set the hour attribute as part of AIDE cron configuration.

'AideMinute': This value is to set the minute attribute as part of AIDE cron configuration.

'AideCronUser': This value is to set the linux user as part of AIDE cron configuration.

'AideEmail': This value sets the email address that receives AIDE reports each time a cron run is made.

'AideMuaPath': This value sets the path to the Mail User Agent that is used to send AIDE reports to the email address set within AideEmail.

Cron configuration

The AIDE TripleO service allows configuration of a cron job. By default it will send reports to /var/log/audit/, unless AideEmail is set, in which case it will instead email the reports to the declared email address.

AIDE and Upgrades

When an upgrade is performed, the AIDE service will automatically regenerate a new integrity database to ensure all upgraded files are correctly recomputed to possess a updated checksum.

If openstack overcloud deploy is called as a subsequent run to an initial deployment and the AIDE configuration rules are changed, the TripleO AIDE service will rebuild the database to ensure the new config attributes are encapsulated in the integrity database.

SecureTTY

SecureTTY allows disabling root access via any console device (tty) by means of entries to the /etc/securetty file.

An environment file can be used to set /etc/securetty entries as follows:

resource_registry:
  OS::TripleO::Services::Securetty: ../deployment/securetty/securetty-baremetal-puppet.yaml

parameter_defaults:
  TtyValues:
    - console
    - tty1
    - tty2
    - tty3
    - tty4
    - tty5
    - tty6

Keystone CADF auditing

Keystone CADF auditing can be enabled by setting `KeystoneNotificationFormat`:

parameter_defaults:
  KeystoneNotificationFormat: cadf

login.defs values

Entries can be made to /etc/login.defs to enforce password characteristics for new users added to the system, for example:

resource_registry:
  OS::TripleO::Services::LoginDefs: ../deployment/login-defs/login-defs-baremetal-puppet.yaml

parameter_defaults:
  PasswordMaxDays: 60
  PasswordMinDays: 1
  PasswordMinLen: 5
  PasswordWarnAge: 7
  FailDelay: 4