Audit Logging

Audit logging in Cassandra logs every incoming CQL command request, Authentication (successful as well as unsuccessful login) to C* node. Currently, there are two implementations provided, the custom logger can be implemented and injected with the class name as a parameter in cassandra.yaml.

  • BinAuditLogger An efficient way to log events to file in a binary format.

  • FileAuditLogger Logs events to audit/audit.log file using slf4j logger.

Recommendation BinAuditLogger is a community recommended logger considering the performance

What does it capture

Audit logging captures following events

  • Successful as well as unsuccessful login attempts.

  • All database commands executed via Native protocol (CQL) attempted or successfully executed.

Limitations

Executing prepared statements will log the query as provided by the client in the prepare call, along with the execution time stamp and all other attributes (see below). Actual values bound for prepared statement execution will not show up in the audit log.

What does it log

Each audit log implementation has access to the following attributes, and for the default text based logger these fields are concatenated with | s to yield the final message.

  • user: User name(if available)

  • host: Host IP, where the command is being executed

  • source ip address: Source IP address from where the request initiated

  • source port: Source port number from where the request initiated

  • timestamp: unix time stamp

  • type: Type of the request (SELECT, INSERT, etc.,)

  • category - Category of the request (DDL, DML, etc.,)

  • keyspace - Keyspace(If applicable) on which request is targeted to be executed

  • scope - Table/Aggregate name/ function name/ trigger name etc., as applicable

  • operation - CQL command being executed

How to configure

Auditlog can be configured using cassandra.yaml. If you want to try Auditlog on one node, it can also be enabled and configured using nodetool.

cassandra.yaml configurations for AuditLog

  • enabled: This option enables/ disables audit log

  • logger: Class name of the logger/ custom logger.

  • audit_logs_dir: Auditlogs directory location, if not set, default to cassandra.logdir.audit or cassandra.logdir
    /audit/

  • included_keyspaces: Comma separated list of keyspaces to be included in audit log, default - includes all keyspaces

  • excluded_keyspaces: Comma separated list of keyspaces to be excluded from audit log, default - excludes no keyspace except system, system_schema and system_virtual_schema

  • included_categories: Comma separated list of Audit Log Categories to be included in audit log, default - includes all categories

  • excluded_categories: Comma separated list of Audit Log Categories to be excluded from audit log, default - excludes no category

  • included_users: Comma separated list of users to be included in audit log, default - includes all users

  • excluded_users: Comma separated list of users to be excluded from audit log, default - excludes no user

List of available categories are: QUERY, DML, DDL, DCL, OTHER, AUTH, ERROR, PREPARE

NodeTool command to enable AuditLog

enableauditlog: Enables AuditLog with yaml defaults. yaml configurations can be overridden using options via nodetool command.

nodetool enableauditlog

Options

--excluded-categories

Comma separated list of Audit Log Categories to be excluded for audit log. If not set the value from cassandra.yaml will be used

--excluded-keyspaces

Comma separated list of keyspaces to be excluded for audit log. If not set the value from cassandra.yaml will be used. Please remeber that system, system_schema and system_virtual_schema are excluded by default, if you are overwriting this option via nodetool, remember to add these keyspaces back if you dont want them in audit logs

--excluded-users

Comma separated list of users to be excluded for audit log. If not set the value from cassandra.yaml will be used

--included-categories

Comma separated list of Audit Log Categories to be included for audit log. If not set the value from cassandra.yaml will be used

--included-keyspaces

Comma separated list of keyspaces to be included for audit log. If not set the value from cassandra.yaml will be used

--included-users

Comma separated list of users to be included for audit log. If not set the value from cassandra.yaml will be used

--logger

Logger name to be used for AuditLogging. Default BinAuditLogger. If not set the value from cassandra.yaml will be used

NodeTool command to disable AuditLog

disableauditlog: Disables AuditLog.

nodetool disableuditlog

NodeTool command to reload AuditLog filters

enableauditlog: NodeTool enableauditlog command can be used to reload auditlog filters when called with default or previous loggername and updated filters

E.g.,

nodetool enableauditlog --loggername <Default/ existing loggerName> --included-keyspaces <New Filter values>

View the contents of AuditLog Files

auditlogviewer is the new tool introduced to help view the contents of binlog file in human readable text format.

auditlogviewer <path1> [<path2>...<pathN>] [options]

Options

-f,--follow
Upon reacahing the end of the log continue indefinitely

waiting for more records

-r,--roll_cycle
How often to roll the log file was rolled. May be

necessary for Chronicle to correctly parse file names. (MINUTELY, HOURLY, DAILY). Default HOURLY.

-h,--help

display this help message

For example, to dump the contents of audit log files on the console

auditlogviewer /logs/cassandra/audit

Sample output

LogMessage: user:anonymous|host:localhost/X.X.X.X|source:/X.X.X.X|port:60878|timestamp:1521158923615|type:USE_KS|category:DDL|ks:dev1|operation:USE "dev1"

Configuring BinAuditLogger

To use BinAuditLogger as a logger in AuditLogging, set the logger to BinAuditLogger in cassandra.yaml under audit_logging_options section. BinAuditLogger can be futher configued using its advanced options in cassandra.yaml.

Adcanced Options for BinAuditLogger

block

Indicates if the AuditLog should block if the it falls behind or should drop audit log records. Default is set to true so that AuditLog records wont be lost

max_queue_weight

Maximum weight of in memory queue for records waiting to be written to the audit log file before blocking or dropping the log records. Default is set to 256 * 1024 * 1024

max_log_size

Maximum size of the rolled files to retain on disk before deleting the oldest file. Default is set to 16L * 1024L * 1024L * 1024L

roll_cycle

How often to roll Audit log segments so they can potentially be reclaimed. Available options are: MINUTELY, HOURLY, DAILY, LARGE_DAILY, XLARGE_DAILY, HUGE_DAILY.For more options, refer: net.openhft.chronicle.queue.RollCycles. Default is set to "HOURLY"

Configuring FileAuditLogger

To use FileAuditLogger as a logger in AuditLogging, apart from setting the class name in cassandra.yaml, following configuration is needed to have the audit log events to flow through separate log file instead of system.log

<!-- Audit Logging (FileAuditLogger) rolling file appender to audit.log -->
<appender name="AUDIT" class="ch.qos.logback.core.rolling.RollingFileAppender">
  <file>${cassandra.logdir}/audit/audit.log</file>
  <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
    <!-- rollover daily -->
    <fileNamePattern>${cassandra.logdir}/audit/audit.log.%d{yyyy-MM-dd}.%i.zip</fileNamePattern>
    <!-- each file should be at most 50MB, keep 30 days worth of history, but at most 5GB -->
    <maxFileSize>50MB</maxFileSize>
    <maxHistory>30</maxHistory>
    <totalSizeCap>5GB</totalSizeCap>
  </rollingPolicy>
  <encoder>
    <pattern>%-5level [%thread] %date{ISO8601} %F:%L - %msg%n</pattern>
  </encoder>
</appender>

<!-- Audit Logging additivity to redirect audt logging events to audit/audit.log -->
<logger name="org.apache.cassandra.audit" additivity="false" level="INFO">
    <appender-ref ref="AUDIT"/>
</logger>