V-235129

Discussion

For completeness of forensic analysis, it is necessary to know how long a user's (or other principal's) connection to the Database Management System (DBMS) lasts. This can be achieved by recording disconnections, in addition to logons/connections, in the audit logs. Disconnection may be initiated by the user or forced by the system (as in a timeout) or result from a system or network failure. To the greatest extent possible, all disconnections must be logged.

Check Content

Check if MySQL audit is configured and enabled. The my.cnf file will set the variable audit_file.

To further check, execute the following query: 
SELECT PLUGIN_NAME, PLUGIN_STATUS
      FROM INFORMATION_SCHEMA.PLUGINS
      WHERE PLUGIN_NAME LIKE 'audit%';

The status of the audit_log plugin must be "active". If it is not "active", this is a finding.

Review audit filters and associated users by running the following queries:
SELECT `audit_log_filter`.`NAME`,
   `audit_log_filter`.`FILTER`
FROM `mysql`.`audit_log_filter`;

SELECT `audit_log_user`.`USER`,
   `audit_log_user`.`HOST`,
   `audit_log_user`.`FILTERNAME`
FROM `mysql`.`audit_log_user`;

All currently defined audits for the MySQL server instance will be listed. If no audits are returned, this is a finding.

To check if the audit filters that are in place are generating records when successful logons or connections occur, log in to MySQL and then log out. 

Below is an example using MySQL Shell:
% mysqlsh —sql
 MySQL  SQL > \connect newuser@localhost
Creating a session to 'newuser@localhost'
 MySQL  localhost:33060+ ssl  SQL > \quit
Bye!

Review the audit log by running the Linux command:
"status": 0 for each indicates successful.
"connection_id": 19 is the same as the connections process id and there will be matching disconnect event with the same connection_id number. This can be used to differentiate multiple connections using the same login.
Each connect and disconnect has a timestamp tag with the time in Coordinated Universal Time (UTC).

sudo cat  <directory where audit log files are located>/audit.log | egrep  "\"event\": \”connect\""
For example if the values returned by - "select @@datadir, @@audit_log_file; " are  /usr/local/mysql/data/,  audit.log
sudo cat  /usr/local/mysql/data/audit.log |egrep "\"event\": \”connect\""

The audit data will look similar to the example below:
Logging in - connecting

{ "timestamp": "2020-08-21 17:47:09", "id": 0, "class": "connection", "event": "connect", "connection_id": 19, "account": { "user": "newuser", "host": "localhost" }, "login": { "user": "newuser", "os": "", "ip": "::1", "proxy": "" }, "connection_data": { "connection_type": "plugin", "status": 0, "db": "" } },

Logging out - disconnection

sudo cat  <directory where audit log files are located>/audit.log | egrep  "\"event\": \"disconnect\”"

{ "timestamp": "2020-08-21 17:47:11", "id": 1, "class": "connection", "event": "disconnect", "connection_id": 19, "account": { "user": "newuser", "host": "localhost" }, "login": { "user": "newuser", "os": "", "ip": "::1", "proxy": "" }, "connection_data": { "connection_type": "plugin" } },