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O19C-00-000100 - Oracle Database must limit the number of concurrent sessions for each system account to an organization-defined number of sessions.

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Information

Database management includes the ability to control the number of users and user sessions using a database management system (DBMS). Unlimited concurrent connections to the DBMS could allow a successful denial-of-service (DoS) attack by exhausting connection resources; and a system can also fail or be degraded by an overload of legitimate users. Limiting the number of concurrent sessions per user is helpful in reducing these risks.

This requirement addresses concurrent session control for a single account. It does not address concurrent sessions by a single user via multiple system accounts; and it does not deal with the total number of sessions across all accounts.

The capability to limit the number of concurrent sessions per user must be configured in or added to the DBMS (for example, by use of a logon trigger), when this is technically feasible. Note that it is not sufficient to limit sessions via a web server or application server alone, because legitimate users and adversaries can potentially connect to the DBMS by other means.

The organization will need to define the maximum number of concurrent sessions by account type, by account, or a combination thereof. In deciding on the appropriate number, it is important to consider the work requirements of the various types of users. For example, two might be an acceptable limit for general users accessing the database via an application; but 10 might be too few for a database administrator using a database management GUI tool, where each query tab and navigation pane may count as a separate session.

(Sessions may also be referred to as connections or logons, which for the purposes of this requirement are synonyms.)

Solution

Limit concurrent connections for each system account to a number less than or equal to the organization-defined number of sessions using the following SQL. Create profiles that conform to the requirements. Assign users to the appropriate profile.

The user profile, ORA_STIG_PROFILE, has been provided with Oracle 19c to satisfy the STIG requirements pertaining to the profile parameters. Oracle recommends that this profile be customized with any site-specific requirements and assigned to all users where applicable. Note: It remains necessary to create a customized replacement for the password validation function, ORA12C_STRONG_VERIFY_FUNCTION, if relying on this technique to verify password complexity.

The defaults for ORA_STIG_PROFILE are set as follows:

Resource Name Limit
--------------------------- -----------------------
COMPOSITE_LIMIT DEFAULT
SESSIONS_PER_USER DEFAULT
CPU_PER_SESSION DEFAULT
CPU_PER_CALL DEFAULT
LOGICAL_READS_PER_SESSION DEFAULT
LOGICAL_READS_PER_CALL DEFAULT
IDLE_TIME 15
CONNECT_TIME DEFAULT
PRIVATE_SGA DEFAULT
FAILED_LOGIN_ATTEMPTS 3
PASSWORD_LIFE_TIME 60
PASSWORD_REUSE_TIME 365
PASSWORD_REUSE_MAX 10
PASSWORD_VERIFY_FUNCTION ORA12C_STRONG_VERIFY_FUNCTION
PASSWORD_LOCK_TIME UNLIMITED
PASSWORD_GRACE_TIME 5

The recommended value for the SESSIONS_PER_USER setting in Oracle 19c is 10 or less. Limiting the number of concurrent sessions can help prevent: Memory resource exhaustion from poorly formed requests, denial-of-service attacks, and one user from tying up all resources.

Change the value of SESSIONS_PER_USER (along with the other parameters, where relevant) from UNLIMITED to DOD-compliant, site-specific requirements for the ORA_STIG_PROFILE and then assign users to the ORA_STIG_PROFILE profile.

Example:
ALTER PROFILE ORA_STIG_PROFILE LIMIT SESSIONS_PER_USER 10;

To assign the user to the profile do the following:
ALTER USER <username> PROFILE ORA_STIG_PROFILE;

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Oracle_Database_19c_V1R1_STIG.zip

Item Details

References: CAT|II, CCI|CCI-000054, Rule-ID|SV-270495r1065198_rule, STIG-ID|O19C-00-000100, Vuln-ID|V-270495

Plugin: OracleDB

Control ID: 624e20cb307f3ed465f7bc2d1df5dd2bba96c600155531f94aa30263fb4f3fa5