| Oracle® Database Security Guide 10g Release 2 (10.2) Part Number B14266-01 |
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View PDF |
| Oracle® Database Security Guide 10g Release 2 (10.2) Part Number B14266-01 |
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|
View PDF |
Security considerations range from requiring backups to be done regularly and stored off-site to narrow table or data considerations, which include ensuring that unauthorized access to sensitive data, such as employee salaries, is precluded by built-in restrictions on every type of access to the table that contains them.
This chapter discusses security policies in the following sections:
This section describes the different aspects of system security policy, and contains the following topics:
Each database has one or more administrators who are responsible for maintaining all aspects of the security policy: the security administrators. If the database system is small, then the database administrator may have the responsibilities of the security administrator. However, if the database system is large, then a special person or group of people may have responsibilities limited to those of a security administrator.
After deciding who will manage the security of the system, a security policy must be developed for every database. A database security policy should include several sub-policies, as explained in the following sections.
Database users are the access paths to the information in an Oracle database. Therefore, tight security should be maintained for the management of database users. Depending on the size of a database system and the amount of work required to manage database users, the security administrator may be the only user with the privileges required to create, alter, or drop database users. On the other hand, there may be a number of administrators with privileges to manage database users. In any case, only trusted individuals should have the powerful privileges to administer database users.
Database users can be authenticated (verified as the correct person) by Oracle using database passwords, the host operating system, network services, or by Secure Sockets Layer (SSL).
Note:
To be authenticated using network authentication services or SSL requires that you have Oracle Advanced Security installed. Refer to the Oracle Database Advanced Security Administrator's Guide for information about these types of authentication.User authentication and how it is specified is discussed in "User Authentication Methods".
The following security issues must also be considered for the operating system environment executing Oracle and any database applications:
Database administrators must have the operating system privileges to create and delete files.
Typical database users should not have the operating system privileges to create or delete files related to the database.
If the operating system identifies database roles for users, then the security administrators must have the operating system privileges to modify the security domain of operating system accounts.
See Also:
Operating-system-specific Oracle documentation for more information about operating system security issuesData security includes the mechanisms that control the access to and use of the database at the object level. Your data security policy determines which users have access to a specific schema object, and the specific types of actions allowed for each user on the object. For example, the policy could establish that user scott can issue SELECT and INSERT statements but not DELETE statements using the emp table. Your data security policy should also define the actions, if any, that are audited for each schema object.
Primarily, the level of security you want to establish for the data in your database determines your data security policy. For example, it may be acceptable to have little data security in a database when you want to allow any user to create any schema object, or grant access privileges for their objects to any other user of the system. Alternatively, it might be necessary for data security to be very controlled when you want to allow only a database or security administrator to create objects and grant access privileges for objects to roles and users.
Overall data security should be based on the sensitivity of data. If information is not sensitive, then the data security policy can be more lax. However, if data is sensitive, then a security policy should be developed to maintain tight control over access to objects.
Some means of implementing data security include system and object privileges, and through roles. A role is a set of privileges grouped together that can be granted to users.
See Also:
Privileges and roles are discussed in Chapter 11, "Administering User Privileges, Roles, and Profiles"Views can also implement data security because their definition can restrict access to table data. They can exclude columns containing sensitive data.
Another means of implementing data security is through fine-grained access control and use of an associated application context. Fine-grained access control is a feature of Oracle Database that enables you to implement security policies with functions, and to associate those security policies with tables or views. In effect, the security policy function generates a WHERE condition that is appended to relevant SQL statements, thereby restricting user access to rows of data in the table or view. An application context is a secure data cache for storing information used to make access control decisions.
This section describes aspects of user security policy, and contains the following topics:
For all types of database users, consider the following general user security issues:
If user authentication is managed by the database, then security administrators should develop a password security policy to maintain database access security. For example, database users should be required to change their passwords at regular intervals, and of course, when their passwords are revealed to others. By forcing a user to modify passwords in such situations, unauthorized database access can be reduced.
Passwords are always automatically and transparently encrypted during network (client/server and server/server) connections, by using a modified Data Encryption Standard (DES) algorithm, before sending them across the network.
Security administrators should consider issues related to privilege management for all types of users. For example, in a database with many user names, it may be beneficial to use roles (named groups of related privileges that you grant to users or other roles) to manage the privileges available to users. Alternatively, in a database with a handful of user names, it may be easier to grant privileges explicitly to users and avoid the use of roles.
Security administrators managing a database with many users, applications, or objects should take advantage of the benefits offered by roles. Roles greatly simplify the task of privilege management in complicated environments.
Security administrators must define a policy for end-user security. If a database has many users, then the security administrator can decide which groups of users can be categorized into user groups, and then create user roles for these groups. The security administrator can grant the necessary privileges or application roles to each user role, and assign the user roles to the users. To account for exceptions, the security administrator must also decide what privileges must be explicitly granted to individual users.
Roles are the easiest way to grant and manage the common privileges needed by different groups of database users.
Consider a situation where every user in the accounting department of a company needs the privileges to run the accounts receivable and accounts payable database applications (ACCTS_REC and ACCTS_PAY). Roles are associated with both applications, and they contain the object privileges necessary to execute those applications.
The following actions, performed by the database or security administrator, address this simple security situation:
Grant the roles for the ACCTS_REC and ACCTS_PAY database applications to the accountant role.
Grant each user of the accounting department the accountant role.
This security model is illustrated in Figure 7-1.
This plan addresses the following potential situations:
If accountants subsequently need a role for a new database application, then the role for that application can be granted to the accountant role, and all users in the accounting department will automatically receive the privileges associated with the new database application. The role for the new application does not need to be granted to individual users requiring use of the application.
Similarly, if the accounting department no longer requires the need for a specific application, then the role associated with that application can be dropped from the accountant role.
If the privileges required by the ACCTS_REC and ACCTS_PAY applications change, then the new privileges can be granted to, or revoked from, the role associated with the application. The security domain of the accountant role, and all users granted the accountant role, automatically reflect the privilege modification.
Use roles in all possible situations to make end-user privilege management efficient and simple.
You can also manage users and their authorizations centrally in a directory service through the enterprise user and enterprise role features of Oracle Advanced Security. See the Oracle Database Advanced Security Administrator's Guide for information about this functionality.
Security administrators should also have a policy addressing database administrator security. For example, when the database is large and there are several types of database administrators, the security administrator may decide to group related administrative privileges into several administrative roles. The administrative roles can then be granted to appropriate administrator users. Alternatively, when the database is small and has only a few administrators, it may be more convenient to create one administrative role and grant it to all administrators.
After database creation, if you used the default passwords for SYS and SYSTEM, then change the passwords for the SYS and SYSTEM administrative user names immediately. Connecting as SYS or SYSTEM gives a user powerful privileges to modify a database. For example, connecting as SYS allows a user to alter data dictionary tables. The privileges associated with these user names are extremely sensitive, and should only be available to select database administrators.
If you have installed options that have caused other administrative user names to be created, then such user name accounts are initially created locked. To unlock these accounts, use the ALTER USER statement. The ALTER USER statement should also be used to change the associated passwords for these accounts.
The passwords for these accounts can be modified by using the procedures described in "Altering Users".
Only database administrators should be able to connect to a database with administrative privileges. For example:
CONNECT username/password AS SYSDBA/SYSOPER
Connecting as SYSOPER gives a user the ability to perform basic operational tasks (such as STARTUP, SHUTDOWN, and recovery operations). Connecting as SYSDBA gives the user these abilities plus unrestricted privileges to perform any actions with a database or the objects within a database (including, CREATE, DROP, and DELETE). Connecting as SYSDBA places a user in the SYS schema, where he can alter data dictionary tables.
Notes:
Connections requested AS SYSDBA or AS SYSOPER must use these phrases; without them, the connection fails. The Oracle parameter 07_DICTIONARY_ACCESSIBILITY is set to FALSE by default, to limit sensitive data dictionary access only to those authorized.
Such connections are authorized only after verification with the password file or with the operating system privileges and permissions. If operating system authentication is used, then the database does not use the supplied user name and password. Operating system authentication is used if there is no password file, or if the supplied user name or password is not in that file, or if no user name and password is supplied.
However, if authentication succeeds by means of the password file, then the connection is logged with the user name. If authentication succeeds by means of the operating system, then it is a CONNECT / connection that does not record the specific user.
Roles are the easiest way to restrict the powerful system privileges and roles required by personnel administrating the database.
Consider a scenario where the database administrator responsibilities at a large installation are shared among several database administrators, each responsible for the following specific database management jobs:
Object creation and maintenance
Database tuning and performance
Creation of new users and granting roles and privileges to database users
Routine database operation (for example: STARTUP, SHUTDOWN, and backup and recovery operations)
Emergency situations, such as database recovery
There are also new, inexperienced database administrators needing limited capabilities to experiment with database management
In this scenario, the security administrator should structure the security for administrative personnel as follows:
Define six roles to contain the distinct privileges required to accomplish each type of job (for example, dba_objects, dba_tune, dba_security, dba_maintain, dba_recov, dba_new).
Grant each role the appropriate privileges.
Grant each type of database administrator the corresponding role.
This plan reduces the likelihood of future problems in the following ways:
If a database administrator job description changes to include more responsibilities, then that database administrator can be granted other administrative roles corresponding to the new responsibilities.
If a database administrator job description changes to include fewer responsibilities, then that database administrator can have the appropriate administrative roles revoked.
The data dictionary always stores information about each role and each user, so information is available to disclose the task of each administrator.
Security administrators must define a special security policy for the application developers using a database. A security administrator could grant the privileges to create necessary objects to application developers. Alternatively, the privileges to create objects could be granted only to a database administrator, who then receives requests for object creation from developers.
Database application developers are unique database users who require special groups of privileges to accomplish their jobs. Unlike end users, developers need system privileges, such as CREATE TABLE, CREATE PROCEDURE, and so on. However, only specific system privileges should be granted to developers to restrict their overall capabilities in the database.
In many cases, application development is restricted to test databases and is not allowed on production databases. This restriction ensures that application developers do not compete with end users for database resources, and that they cannot detrimentally affect a production database.
After an application has been thoroughly developed and tested, it is permitted access to the production database and made available to the appropriate end users of the production database.
The database administrator can define the following options when determining which privileges should be granted to application developers:
An application developer is allowed to create new schema objects, including tables, indexes, procedures, packages, and so on. This option allows the application developer to develop an application independent of other objects.
An application developer is not allowed to create new schema objects. A database administrator creates all required tables, indexes, procedures, and so on, as requested by an application developer. This option allows the database administrator to completely control the space usage of a database and the access paths to information in the database.
Although some database systems use only one of these options, other systems could mix them. For example, application developers can be allowed to create new stored procedures and packages, but not allowed to create tables or indexes. Security administrators should base their decision on the following:
The control desired over the space usage of a database
The control desired over the access paths to schema objects
The database used to develop applications If a test database is being used for application development, then a more liberal development policy would be in order.
Security administrators can create roles to manage the privileges required by the typical application developer. For example, a typical role named APPLICATION_DEVELOPER might include the CREATE TABLE, CREATE VIEW, and CREATE PROCEDURE system privileges. Consider the following when defining roles for application developers:
CREATE system privileges are usually granted to application developers so that they can create their own objects. However, CREATE ANY system privileges, which allow a user to create an object in any user schema, are not usually granted to developers. This restricts the creation of new objects only to the developer user account.
Object privileges are rarely granted to roles used by application developers, because granting object privileges through roles often restricts their usability in creating other objects (primarily views and stored procedures). It is more practical to allow application developers to create their own objects for development purposes.
While application developers are typically given the privileges to create objects as part of the development process, security administrators must maintain limits on what and how much database space can be used by each application developer. For example, as the security administrator, you should specifically set limits or restrict access to the following for each application developer:
The tablespaces in which the developer can create tables or indexes
The quota for each tablespace accessible to the developer
Both limitations can be set by altering a developer's security domain. This is discussed in Altering Users.
In large database systems with many database applications, you might consider assigning application administrators. An application administrator is responsible for the following types of tasks:
Creating roles for an application and managing the privileges of each application role
Creating and managing the objects used by a database application
Maintaining and updating the application code and Oracle procedures and packages as necessary
Often, an application administrator is also the application developer who designed an application. However, an application administrator could be any individual familiar with the database application.
Database security systems that are dependent on passwords require that passwords be kept secret at all times. Because passwords are vulnerable to theft, forgery, and misuse, Oracle Database uses a password management policy. DBAs and security officers control this policy through user profiles, enabling greater control over database security.
Use the CREATE PROFILE statement to create a user profile. The profile is assigned to a user with the CREATE USER or ALTER USER statement. Details of creating and altering database users are not discussed in this section. This section is concerned with the password parameters that can be specified using the CREATE PROFILE (or ALTER PROFILE) statement.
This section contains the following topics relating to Oracle password management:
Password Complexity Verification
See Also:
Oracle Database SQL Reference for syntax and specific information about SQL statements discussed in this section
When a particular user exceeds a designated number of failed login attempts, the server automatically locks that user account. You specify the permissible number of failed login attempts using the CREATE PROFILE statement. You can also specify the amount of time accounts remain locked.
In the following example, the maximum number of failed login attempts for the user johndoe is four, and the amount of time the account will remain locked is 30 days. The account will unlock automatically after the passage of 30 days.
CREATE PROFILE prof LIMIT
FAILED_LOGIN_ATTEMPTS 4
PASSWORD_LOCK_TIME 30;
ALTER USER johndoe PROFILE prof;
If you do not specify a time interval for unlocking the account, then PASSWORD_LOCK_TIME assumes the value specified in a default profile. If you specify PASSWORD_LOCK_TIME as UNLIMITED, then the account must be explicitly unlocked using an ALTER USER statement. For example, assuming that PASSWORD_LOCK_TIME UNLIMITED is specified for johndoe, then the following statement must be used to unlock the account:
ALTER USER johndoe ACCOUNT UNLOCK;
After a user successfully logs into an account, the unsuccessful login attempt count for the user, if it exists, is reset to 0.
The security officer can also explicitly lock user accounts. When this occurs, the account cannot be unlocked automatically, and only the security officer should unlock the account. The CREATE USER or ALTER USER statements are used to explicitly lock or unlock user accounts. For example, the following statement locks the user account, susan:
ALTER USER susan ACCOUNT LOCK;
Use the CREATE PROFILE statement to specify a maximum lifetime for passwords. When the specified amount of time passes and the password expires, the user or DBA must change the password. The following statements create and assign a profile to user johndoe, and the PASSWORD_LIFE_TIME clause specifies that johndoe can use the same password for 90 days before it expires.
CREATE PROFILE prof LIMIT FAILED_LOGIN_ATTEMPTS 4 PASSWORD_LOCK_TIME 30 PASSWORD_LIFE_TIME 90; ALTER USER johndoe PROFILE prof;
You can also specify a grace period for password expiration. Users enter the grace period upon the first attempt to log in to a database account after their password has expired. During the grace period, a warning message appears each time users try to log in to their accounts, and continues to appear until the grace period expires. Users must change the password within the grace period. If the password is not changed within the grace period, then users are prompted for a new password each time an attempt is made to access their accounts. Access to an account is denied until a new password is supplied.
Figure 7-2 shows the chronology of the password lifetime and grace period.
Figure 7-2 Chronology of Password Lifetime and Grace Period
In the following example, the profile assigned to johndoe includes the specification of a grace period: PASSWORD_GRACE_TIME = 3. The first time johndoe tries to log in to the database after 90 days (this can be any day after the 90th day, that is, the 70th day, 100th day, or another day), he receives a warning message that his password will expire in three days. If three days pass, and he does not change her password, then the password expires. After this, he receives a prompt to change his password on any attempt to log in, and cannot log in until he does so.
CREATE PROFILE prof LIMIT FAILED_LOGIN_ATTEMPTS 4 PASSWORD_LOCK_TIME 30 PASSWORD_LIFE_TIME 90 PASSWORD_GRACE_TIME 3; ALTER USER johndoe PROFILE prof;
Oracle provides a means of explicitly expiring a password. The CREATE USER and ALTER USER statements provide this functionality. The following statement creates a user with an expired password. This setting forces the user to change the password before the user can log in to the database.
CREATE USER jbrown
IDENTIFIED BY zX83yT
...
PASSWORD EXPIRE;
The following two parameters control user ability to reuse an old password:
Table 7-1 Parameters Controlling Reuse of an Old Password
If you specify neither, then the user can reuse passwords at any time, which is not a good security practice.
If neither parameter is UNLIMITED, then password reuse is allowed, but only after meeting both conditions. The user must have changed the password the specified number of times, and the specified number of days must have passed since the old password was last used.
For example, suppose that the user A's profile had PASSWORD_REUSE_MAX set to 10 and PASSWORD_REUSE_TIME set to 30. Then user A cannot reuse a password until the password has been reset 10 times, and until 30 days had passed since the password was last used.
If either parameter is specified as UNLIMITED, then the user can never reuse a password.
If both parameters are set to UNLIMITED, then Oracle ignores both, and the user can reuse any password at any time.
Note:
If you specifyDEFAULT for either parameter, then Oracle uses the value defined in the DEFAULT profile, which sets all parameters to UNLIMITED. Oracle thus uses UNLIMITED for any parameter specified as DEFAULT, unless you change the setting for that parameter in the DEFAULT profile.Oracle sample password complexity verification routine can be specified using a PL/SQL script (UTLPWDMG.SQL), which sets the default profile parameters.
The password complexity verification routine ensures that the password meets the following requirements:
Is at least four characters long
Differs from the user name
Has at least one alpha, one numeric, and one punctuation mark character
Is not simple or obvious, such as welcome, account, database, or user
Differs from the previous password by at least 3 characters
Note:
TheALTER USER command now has a REPLACE clause by using which users can change their own unexpired passwords by supplying the old password to authenticate themselves.
If the password has expired, then the user cannot log in to SQL to issue the ALTER USER command. Instead, the OCIPasswordChange() function must be used, which also requires the old password.
A DBA with ALTER ANY USER privilege can alter any user password (force a new password) without supplying the old one.
You can enhance the existing password verification complexity routine or create other password verification routines using PL/SQL or third-party tools.
The PL/SQL call must adhere to the following format:
routine_name ( userid_parameter IN VARCHAR(30), password_parameter IN VARCHAR (30), old_password_parameter IN VARCHAR (30) ) RETURN BOOLEAN
After a new routine is created, it must be assigned as the password verification routine by using the user profile or the system default profile.
CREATE/ALTER PROFILE profile_name LIMIT
PASSWORD_VERIFY_FUNCTION routine_name
The password verification routine must be owned by the SYS user.
You can use the following sample password verification routine as a model when developing your own complexity checks for a new password.
The default password complexity function performs the following minimum complexity checks:
The password satisfies minimum length requirements.
The password is not the username. You can modify this function based on your requirements.
This function must be created in SYS schema, and you must CONNECT SYS/password AS SYSDBA before running the script.
CREATE OR REPLACE FUNCTION verify_function
(username varchar2,
password varchar2,
old_password varchar2)
RETURN boolean IS
n boolean;
m integer;
differ integer;
isdigit boolean;
ischar boolean;
ispunct boolean;
digitarray varchar2(20);
punctarray varchar2(25);
chararray varchar2(52);
BEGIN
digitarray:= '0123456789';
chararray:= 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
punctarray:='!"#$%&()''*+,-/:;<=>?_';
--Check if the password is same as the username
IF password = username THEN
raise_application_error(-20001, 'Password same as user');
END IF;
--Check for the minimum length of the password
IF length(password) < 4 THEN
raise_application_error(-20002, 'Password length less than 4');
END IF;
--Check if the password is too simple. A dictionary of words may be
--maintained and a check may be made so as not to allow the words
--that are too simple for the password.
IF NLS_LOWER(password) IN ('welcome', 'database', 'account', 'user',
'password', 'oracle', 'computer', 'abcd')
THEN raise_application_error(-20002, 'Password too simple');
END IF;
--Check if the password contains at least one letter,
--one digit and one punctuation mark.
--1. Check for the digit
--You may delete 1. and replace with 2. or 3.
isdigit:=FALSE;
m := length(password);
FOR i IN 1..10 LOOP
FOR j IN 1..m LOOP
IF substr(password,j,1) = substr(digitarray,i,1) THEN
isdigit:=TRUE;
GOTO findchar;
END IF;
END LOOP;
END LOOP;
IF isdigit = FALSE THEN
raise_application_error(-20003, 'Password should contain at least one \
digit, one character and one punctuation');
END IF;
--2. Check for the character
<<findchar>>
ischar:=FALSE;
FOR i IN 1..length(chararray) LOOP
FOR j IN 1..m LOOP
IF substr(password,j,1) = substr(chararray,i,1) THEN
ischar:=TRUE;
GOTO findpunct;
END IF;
END LOOP;
END LOOP;
IF ischar = FALSE THEN
raise_application_error(-20003, 'Password should contain at least one digit,\
one character and one punctuation');
END IF;
--3. Check for the punctuation
<<findpunct>>
ispunct:=FALSE;
FOR i IN 1..length(punctarray) LOOP
FOR j IN 1..m LOOP
IF substr(password,j,1) = substr(punctarray,i,1) THEN
ispunct:=TRUE;
GOTO endsearch;
END IF;
END LOOP;
END LOOP;
IF ispunct = FALSE THEN raise_application_error(-20003, 'Password should \
contain at least one digit, one character and one punctuation');
END IF;
<<endsearch>>
--Check if the password differs from the previous password by at least 3 letters
IF old_password = '' THEN
raise_application_error(-20004, 'Old password is null');
END IF;
--Everything is fine; return TRUE ;
differ := length(old_password) - length(password);
IF abs(differ) < 3 THEN
IF length(password) < length(old_password) THEN
m := length(password);
ELSE
m:= length(old_password);
END IF;
differ := abs(differ);
FOR i IN 1..m LOOP
IF substr(password,i,1) != substr(old_password,i,1) THEN
differ := differ + 1;
END IF;
END LOOP;
IF differ < 3 THEN
raise_application_error(-20004, 'Password should differ by at \
least 3 characters');
END IF;
END IF;
--Everything is fine; return TRUE ;
RETURN(TRUE);
END;
Security administrators should define a policy for the auditing procedures of each database. You may, for example, decide to have database auditing disabled unless questionable activities are suspected. When auditing is required, the security administrator must decide what level of detail to audit the database; usually, general system auditing is followed by more specific types of auditing after the origins of suspicious activity are determined. In addition to standard database auditing, Oracle Database supports fine-grained auditing using policies that can monitor multiple specific objects, columns, and statements, including INDEX.
See Also:
Auditing is discussed in Chapter 8, "Database Auditing: Security Considerations" and Chapter 12, "Configuring and Administering Auditing".Information security and privacy and protection of corporate assets and data are of pivotal importance in any business. Oracle Database comprehensively addresses the need for information security by offering cutting-edge security features such as deep data protection, auditing, scalable security, secure hosting and data exchange.
The Oracle Database server leads the industry in security. However, in order to fully maximize the security features offered by Oracle Database in any business environment, it is imperative that the database itself be well-protected. Furthermore, proper use of its security features and adherence to basic security practices will help protect against database-related threats and attacks. Such an approach provides a much more secure operating environment for Oracle Database.
This security checklist provides guidance on configuring Oracle Database in a secure manner by adhering to and recommending industry-standard and advisable "security practices" for operational database deployments.
Before looking at the more detailed checklist: consider all paths the data travels and assess the threats that impinge on each path and node. Then, take steps to lessen or eliminate both the threats and the consequences of a successful breach of security. Monitoring and auditing to detect either increased threat levels or successful penetration increases the likelihood of preventing and minimizing security losses.
Details on specific database-related tasks and actions can be found throughout the Oracle documentation set.
The following security checklist includes guidelines that help secure your database:
Install only what is required.
Options and Products
The Oracle Database CD pack contains a host of options and products in addition to the database server. Install additional products and options only as necessary. Use Custom Installation to avoid installing unnecessary products or, perform a typical installation, and then deinstall unrequired options and products. There is no need to maintain additional products and options if they are not being used. They can always be properly and easily reinstalled as required.
Sample Schemas
Oracle Corporation provides Sample Schemas to provide a common platform for examples. If your database will be used in a production environment, then do not install the Sample Schema. If you have installed the Sample Schema on a test database, then before going production, remove or relock the Sample Schema accounts.
Lock and expire default user accounts.
Oracle Database installs with a number of default (preset) database server user accounts. Upon successful installation of the database server, the Database Configuration Assistant automatically locks and expires most default database user accounts.
If a manual (without using Database Configuration Assistant) installation of Oracle Database is performed, then no default database users are locked upon successful installation of the database server. Left open in their default states, these user accounts can be exploited to gain unauthorized access to data or disrupt database operations.
Therefore, after performing any kind of initial installation that does not use the Database Configuration Assistant, you should lock and expire all default database user accounts. Oracle Database provides SQL statements to perform such operations.
Installing additional products and components later also results in creating more default database server accounts. Database Configuration Assistant automatically locks and expires all additionally created database server user accounts. Unlock only those accounts that need to be accessed on a regular basis and assign a strong, meaningful password to each of these unlocked accounts. Oracle provides SQL and password management to perform such operations.
Table 7-2 shows the database users after a typical Oracle Database installation using Database Configuration Assistant.
Table 7-2 Default Accounts and Their Status (Standard Installation)
If any default database server user account other than the ones left open is required for any reason, then a database administrator (DBA) need simply unlock and activate that account with a new, secure password.
The preceding list of accounts depends on whether you choose to install Enterprise Manager. If so, SYSMAN and DBSNMP are open as well, unless you configure Enterprise Manager for Central Administration. In this case, the SYSMAN account (if present) will be locked as well.
If you do not install Enterprise Manager, then only SYS and SYSTEM are open. Database Configuration Assistant locks and expires all other accounts (including SYSMAN and DBSNMP).
Change default user passwords.
The most trivial method by which Oracle Database can be compromised is a default database server user account which still has a default password associated with it even after installation. The following guidelines are recommended:
Change default passwords of administrative users.
Oracle Database 10g enables you to use the same or different passwords for the SYS, SYSTEM, SYSMAN and DBSNMP administrative accounts. Use different passwords for each: in any Oracle environment (production or test), assign strong, secure, and distinct passwords to these administrative accounts. If Database Configuration Assistant is used, then it requires you to enter passwords for the SYS and SYSTEM accounts, disallowing the use of the defaults CHANGE_ON_INSTALL and MANAGER.
Similarly, for production environments, do not use default passwords for any administrative accounts, including SYSMAN and DBSNMP.
At the end of database creation, Database Configuration Assistant displays a page requiring you to enter and confirm new passwords for the SYS and SYSTEM user accounts.
Change default passwords of all users.
In Oracle Database, SCOTT no longer installs with default password TIGER, but instead is locked and expired, as is DBSNMP. Each of the other accounts install with a default password that is exactly the same as that user account (For example, user MDSYS installs with the password MDSYS).
If any of the default user accounts that were locked and expired upon installation need to be activated, then assign a new secure password to each such user account.
Even though Oracle does not explicitly mandate changing the default password for the user SCOTT, Oracle recommends that this user account also be locked in a production environment.
Enforce password management.
Oracle recommends that basic password management rules (such as password length, history, complexity, and so forth) as provided by the database be applied to all user passwords and that all users be required to change their passwords periodically.
Oracle also recommends, if possible, using Oracle Advanced Security (an option to the Enterprise Edition of Oracle Database) with network authentication services (such as Kerberos), token cards, smart cards or X.509 certificates. These services enable strong authentication of users to provide better protection against unauthorized access to Oracle Database.
Enable data dictionary protection.
Oracle recommends that customers implement data dictionary protection to prevent users having the ANY system privileges from using such privileges on the data dictionary.
To enable dictionary protection, set the following configuration parameter to FALSE, in the init<sid>.ora control file:
O7_DICTIONARY_ACCESSIBILITY = FALSE
By doing so, only those authorized users making DBA-privileged (for example CONNECT / AS SYSDBA) connections can use the ANY system privilege on the data dictionary. If O7_DICTIONARY_ACCESSIBILITY is not set to FALSE, then any user with a DROP ANY TABLE (for example) system privilege will be able to maliciously drop parts of the data dictionary.
However, if a user needs view access to the data dictionary, then it is permissible to grant that user the SELECT ANY DICTIONARY system privilege.
Notes:
Regarding O7_DICTIONARY_ACCESSIBILITY, note that in Oracle Database, the default is FALSE. However, in Oracle8i, this parameter is set to TRUE by default and must specifically be changed to FALSE to enable this security feature.
Regarding the SELECT ANY DICTIONARY privilege: this privilege is not included in the GRANT ALL PRIVILEGES statement, but it can be granted through a role.
Practice the principle of least privilege.
The following guidelines are recommended:
Grant necessary privileges only.
Do not provide database users more privileges than are necessary. In other words, the principle of least privilege is that users be given only those privileges that are actually required to efficiently perform their jobs.
To implement this principle, restrict the following as much as possible:
1) The number of SYSTEM and OBJECT privileges granted to database users, and
2) The number of people who are allowed to make SYS-privileged connections to the database.
For example, there is generally no need to grant CREATE ANY TABLE to any non-DBA-privileged user.
Revoke unnecessary privileges from the PUBLIC user group.
Revoke all unnecessary privileges and roles from the database server user group PUBLIC. PUBLIC acts as a default role granted to every user in an Oracle database. Any database user can exercise privileges that are granted to PUBLIC. Such privileges include EXECUTE on various PL/SQL packages, potentially enabling a minimally-privileged user to access and execute functions that he would not otherwise be permitted to access directly. The more powerful packages that may potentially be misused are listed in the following table:
| Package | Description |
|---|---|
UTL_SMTPFoot 1 |
This package permits arbitrary mail messages to be sent from one arbitrary user to another arbitrary user. Granting this package to PUBLIC may permit unauthorized exchange of mail messages. |
UTL_TCP1 |
This package permits outgoing network connections to be established by the database server to any receiving (or waiting) network service. Thus, arbitrary data may be sent between the database server and any waiting network service. |
UTL_HTTP1 |
This package allows the database server to request and retrieve data using HTTP. Granting this package to PUBLIC may permit using HTML forms to send data to a malicious Web site. |
UTL_FILE1 |
If configured improperly, then this package allows text level access to any file on the host operating system. Even when properly configured, this package may allow unauthorized access to sensitive operating system files, such as trace files, because it does not distinguish between its calling applications. The result can be that one application accessing UTL_FILE may write arbitrary data into the same location that is written to by another application. |
DBMS_RANDOM |
This package can be used to encrypt stored data. Generally, most users should not have the privilege to encrypt data since encrypted data may be non-recoverable if the keys are not securely generated, stored, and managed. |
These packages are extremely useful to the applications that need them. They require proper configuration and usage for safe and secure operation, and may not be suitable for most applications.
For applications that need these packages, create roles with EXECUTE privilege on the particular packages needed and assign those roles only to applications that specifically need to use them. Oracle intends to revoke such privileges from PUBLIC in subsequent releases.
Grant a role to users only if they need all privileges of the role.
Roles (groups of privileges) are useful for quickly and easily granting permissions to users. Although you can use Oracle-defined roles, you have more control and continuity if you create your own roles containing only the privileges pertaining to your requirements. Oracle may change or remove the privileges in an Oracle-defined role, as it has with CONNECT, which now has only the CREATE SESSION privilege. Formerly this role had eight other privileges. Both CONNECT and RESOURCE roles will be deprecated in future Oracle versions.
Ensure that the roles you define contain only the privileges that reflect job responsibility. If your application users do not need all the privileges encompassed by an existing role, then apply a different set of roles that supply just the right privileges. Alternatively, create and assign a more restricted role.
For example, it is imperative to strictly limit the privileges of SCOTT. Drop the CREATE DBLINK privilege for SCOTT. Then drop the entire role for the user, because privileges acquired by means of a role cannot be dropped individually. Recreate your own role with only the privileges needed, and grant that new role to that user. Similarly, for even better security, drop the CREATE DBLINK privilege from all users who do not require it.
Restrict permissions on run-time facilities.
Do not assign all permissions to any database server run-time facility such as the Oracle Java Virtual Machine (OJVM). Grant specific permissions to the explicit document root file paths for such facilities that may execute files and packages outside the database server.
Here is an example of a vulnerable run-time call:
call dbms_java.grant_permission('SCOTT', 'SYS:java.io.FilePermission','<<ALL FILES>>','read');
Here is an example of a better (more secure) run-time call:
call dbms_java.grant_permission('SCOTT', 'SYS:java.io.FilePermission','<<actual directory path>>','read');
Enforce access controls effectively and authenticate clients stringently.
Authenticate clients properly.
By default, Oracle allows operating-system-authenticated logins only over secure connections, which precludes using Oracle Net and a shared server configuration. This default restriction prevents a remote user from impersonating another operating system user over a network connection.
Setting the initialization parameter REMOTE_OS_AUTHENT to TRUE forces the RDBMS to accept the client operating system user name received over a nonsecure connection and use it for account access. Since clients, such as PCs, are not trusted to perform operating system authentication properly, it is very poor security practice to turn on this feature.
The default setting, REMOTE_OS_AUTHENT = FALSE, creates a more secure configuration that enforces proper, server-based authentication of clients connecting to an Oracle database.
You should not alter the default setting of the REMOTE_OS_AUTHENT initialization parameter, which is FALSE.
Setting this parameter to FALSE does not mean that users cannot connect remotely. It simply means that the database will not trust that the client has already authenticated, and will therefore apply its standard authentication processes.
Restrict operating system access.
Limit the number of operating system users. Limit the privileges of the operating system accounts (administrative, root-privileged or DBA) on the Oracle Database host (physical machine) to the least privileges needed for the user's tasks.
Oracle also recommends:
Restricting the ability to modify the default file and directory permissions for the Oracle Database home (installation) directory or its contents. Even privileged operating system users and the Oracle owner should not modify these permissions, unless instructed otherwise by Oracle.
Restricting symbolic links. Ensure that when providing a path or file to the database, neither the file nor any part of the path is modifiable by an untrusted user. The file and all components of the path should be owned by the DBA or some trusted account, such as root.
This recommendation applies to all types of files: data files, log files, trace files, external tables, bfiles, and so on.
The following guidelines are recommended:
Keep the database server behind a firewall. Oracle Database network infrastructure, Oracle Net (formerly known as Net8 and SQL*Net), offers support for a variety of firewalls from various vendors. Supported proxy-enabled firewalls include' Gauntlet from Network Associates and Raptor from Axent . Supported packet-filtering firewalls include PIX Firewall from Cisco, and supported stateful inspection firewalls (more sophisticated packet-filtered firewalls) include Firewall-1 from CheckPoint .
Never poke a hole through a firewall.
If Oracle Database is behind a firewall, then do not, under any circumstances, poke a hole through the firewall. For example, do not leave open port 1521 for Oracle Listener to make a connection to the Internet or vice versa.
Doing this will introduce a number of significant security vulnerabilities including more port openings through the firewall, multi-threaded operating system server issues, and revelation of crucial information on databases behind the firewall. Furthermore, an Oracle Listener running without an established password may be probed for critical details about the databases on which it is listening such as trace and logging information, banner information and database descriptors and service names.
All this information and the availability of an ill-configured firewall will provide an attacker ample opportunity to launch malicious attacks on the target databases.
Protect the Oracle listener.
Because the listener acts as the database gateway to the network, it is important to limit the consequences of malicious interference:
Restrict the privileges of the listener, so that it cannot read or write files in the database or the Oracle server address space.
This restriction prevents external procedure agents spawned by the listener (or procedures executed by such an agent) from inheriting the ability to do such reads or writes. The owner of this separate listener process should not be the owner that installed Oracle or executes the Oracle instance (such as ORACLE, the default owner).
EXTPROC_LISTENER=
(DESCRIPTION=
(ADDRESS=
(PROTOCOL=ipc)(KEY=extproc)))
SID_LIST_EXTPROC_LISTENER=
(SID_LIST=
(SID_DESC=
(SID_NAME=plsextproc)
(ORACLE_HOME=/u1/app/oracle/9.0)
(PROGRAM=extproc)))
Secure administration of the database by doing the following:
i. Prevent online administration by requiring the administrator to have write privileges on the LISTENER.ORA file and the listener password:
Add or alter this line in the LISTENER.ORA file
ADMIN_RESTRICTIONS_LISTENER=ON
Then RELOAD the configuration.
ii. Use SSL when administering the listener, by making the TCPS protocol the first entry in the address list as follows:
LISTENER=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS=
(PROTOCOL=tcps)
(HOST = ed-pdsun1.us.oracle.com)
(PORT = 8281)))
To administer the listener remotely, you need to define the listener in the listener.ora file on the client computer. For example, to access listener USER281 remotely, use the following configuration:
user281 =
(DESCRIPTION =
(ADDRESS =
(PROTOCOL = tcps)
(HOST = ed-pdsun1.us.oracle.com)
(PORT = 8281))
)
)
iii. Always establish a secure, well-formed password for the Oracle listener to prevent remote configuration of the Oracle listener. Password protect the listener as follows:
LSNRCTL> CHANGE_PASSWORD Old password: lsnrc80 New password: lsnrc90 Reenter new password: lsnrc90 LSNRCTL> SET PASSWORD Password: The command completed successfully LSNRCTL> SAVE_CONFIG The command completed successfully
Remove the external procedure configuration from the listener.ora file if you do not intend to use such procedures.
Monitor listener activity.
Monitor who accesses your systems.
Authenticating client computers over the Internet is problematic. Do user authentication instead, which avoids client system issues that include falsified IP addresses, hacked operating systems or applications, and falsified or stolen client system identities. The following steps improve client computer security:
Configure the connection to use SSL. Using SSL (Secure Sockets Layer) communication makes eavesdropping unfruitful and enables the use of certificates for user and server authentication.
Set up certificate authentication for clients and servers such that:
i. The organization is identified by unit and certificate issuer and the user is identified by distinguished name and certificate issuer.
ii. Applications test for expired certificates.
iii. Certificate revocation lists are audited.
Use the Oracle Net valid node checking security feature to allow or deny access to Oracle server processes from network clients with specified IP addresses. To use this feature, set the following protocol.ora (Oracle Net configuration file) parameters:
tcp.validnode_checking = YES
tcp.excluded_nodes = {list of IP addresses}
tcp.invited_nodes = {list of IP addresses}
The first parameter turns on the feature whereas the latter parameters respectively deny and allow specific client IP addresses from making connections to the Oracle listener (This helps in preventing potential Denial of Service attacks).
If possible, use Oracle Advanced Security to encrypt network traffic between clients, databases, and application servers.
Harden the host operating system by disabling all unnecessary operating system services. Both UNIX and Windows platforms provide a variety of operating system services, most of which are not necessary for most deployments. Such services include FTP, TFTP, TELNET, and so forth. Be sure to close both the UDP and TCP ports for each service that is being disabled. Disabling one type of port and not the other does not make the operating system more secure.
Apply all security patches and workarounds.
Always apply all relevant and current security patches for both the operating system on which Oracle Database resides and Oracle Database itself, and for all installed Oracle Database options and components.
Periodically check the security site on Oracle Technology Network for details on security alerts released by Oracle Corporation at
http://www.oracle.com/technology/deploy/security/alerts.htm
Also check Oracle Worldwide Support Service site, Metalink, for details on available and upcoming security-related patches at
http://metalink.oracle.com
Contact Oracle Security Products if you come across a vulnerability in Oracle Database.
If you believe that you have found a security vulnerability in Oracle Database, then submit an iTAR to Oracle Worldwide Support Services using Metalink, or e-mail a complete description of the problem, including product version and platform, together with any exploit scripts and examples to the following address:
secalert_us@oracle.com
