| Oracle® Database Security Guide 10g Release 1 (10.1) Part Number B10773-01 |
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| Oracle® Database Security Guide 10g Release 1 (10.1) Part Number B10773-01 |
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View PDF |
The idea of security policies includes many dimensions. Broad considerations include requiring backups to be done regularly and stored off-site. Narrow table or data considerations 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 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, the database administrator may have the responsibilities of the security administrator. However, if the database system is large, 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's 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. Regardless, 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).
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Note: To be authenticated using network authentication services or SSL, requires that you have installed Oracle Advanced Security. Refer to the Oracle 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:
Data 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.
Your data security policy is determined primarily by the level of security you want to establish for the data in your database.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 make a database or security administrator the only person with the privileges 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, 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. Privileges and roles are discussed in Chapter 10, "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, 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, using a modified DES (Data Encryption Standard) 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 usernames, it may be beneficial to use roles (which are 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 usernames, 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, 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:
accountant.ACCTS_REC and ACCTS_PAY database applications to the accountant role.accountant role.This security model is illustrated in Figure 7-1.
Text description of the illustration admin003.gif
This plan addresses the following potential situations:
accountant role, and all users in the accounting department will automatically receive the privileges associated with the new database application. The application's role does not need to be granted to individual users requiring use of the application.accountant role.ACCTS_REC and ACCTS_PAY applications change, the new privileges can be granted to, or revoked from, the application's role. 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 Advanced Security Administrator's Guide for information about this functionality.
Security administrators should 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, and if you used the default passwords for SYS and SYSTEM, immediately change the passwords for the SYS and SYSTEM administrative usernames. 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 usernames are extremely sensitive, and should only be available to select database administrators.
If you have installed options that have caused other administrative usernames to be created, such username 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 using the procedures described in "Altering Users".
Only database administrators should have the capability 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 do anything to 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.
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:
STARTUP, SHUTDOWN, and backup and recovery operations)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:
dba_objects, dba_tune, dba_security, dba_maintain, dba_recov, dba_new).This plan diminishes the likelihood of future problems in the following ways:
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. Or, 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. All required tables, indexes, procedures, and so on are created by a database administrator, as requested by an application developer. This option allows the database administrator to completely control a database's space usage 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. A security administrator's decision regarding this issue should be based on the following:
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's schema, are not usually granted to developers. This restricts the creation of new objects only to the developer's user account.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 or restrict the following limits for each application 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:
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. Since passwords are vulnerable to theft, forgery, and misuse, Oracle Database has DBAs and security officers control password management policy through user profiles, enabling greater control over database security.
You 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:
See Also:
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When a particular user exceeds a designated number of failed login attempts, the server automatically locks that user's 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 ashwini 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 ashwini PROFILE prof;
If you do not specify a time interval for unlocking the account, PASSWORD_LOCK_TIME assumes the value specified in a default profile. If you specify PASSWORD_LOCK_TIME as UNLIMITED, the account must be explicitly unlocked using an ALTER USER statement. For example, assuming that PASSWORD_LOCK_TIME UNLIMITED is specified for ashwini, then the following statement must be used to unlock the account:
ALTER USER ashwini ACCOUNT UNLOCK;
After a user successfully logs into an account, that user's unsuccessful login attempt count, if there is one, 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 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 ashwini, and the PASSWORD_LIFE_TIME clause specifies that ashwini 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 ashwini 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, thereafter 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.
Text description of the illustration admin024.gif
In the following example, the profile assigned to ashwini includes the specification of a grace period: PASSWORD_GRACE_TIME = 3. The first time ashwini 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), she receives a warning message that her password will expire in three days. If three days pass, and she does not change her password, the password expires. Thereafter, she receives a prompt to change her password on any attempt to log in, and cannot log in until she does so.
CREATE PROFILE prof LIMIT FAILED_LOGIN_ATTEMPTS 4 PASSWORD_LOCK_TIME 30 PASSWORD_LIFE_TIME 90 PASSWORD_GRACE_TIME 3; ALTER USER ashwini 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 the user's ability to reuse an old password:
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Parameter Name |
Description and Use |
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PASSWORD_REUSE_TIME |
requires either |
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PASSWORD_REUSE_MAX |
requires either |
If you specify neither, the user can reuse passwords at any time, which is not a "security best practice."
If neither parameter is UNLIMITED, 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 user A's profile had PASSWORD_REUSE_MAX set to 10 and PASSWORD_REUSE_TIME set to 30. Then user A could not reuse a password until she had reset her password ten times, and 30 days had passed since she last used that password.
If either parameter is specified as UNLIMITED, the user can never reuse a password.
If both parameters are set to UNLIMITED, Oracle ignores both, and the user can reuse any password at any time.
Oracle's 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:
welcome, account, database, or userYou 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 using the user's profile or the system default profile.
CREATE/ALTER PROFILE profile_name LIMIT PASSWORD_VERIFY_FUNCTION routine_name
The password verify routine must be owned by SYS.
You can use this 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:
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 supports fine-grained auditing using policies that can monitor multiple specific objects, columns, and statements, including INDEX.
Auditing is discussed in Chapter 8, "Database Auditing: Security Considerations" and Chapter 11, "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 the Oracle Database database.
This security checklist provides guidance on configuring Oracle Database in a secure manner by adhering to and recommending industry-standard "best security practices" for operational database deployments.
In simple summary, 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 those 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 or minimizing security losses.
Details on specific database-related tasks and actions can be found throughout the Oracle documentation set.
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, following a typical installation, deinstall unneeded options and products. There is no need to maintain the 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, do not install the Sample Schema. If you have installed the Sample Schema on a test database, then before going production, remove or re-lock the Sample Schema 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 (not utilizing Database Configuration Assistant) installation of Oracle Database is performed, no default database users are locked upon successful installation of the database server. If 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 utilize Database Configuration Assistant, you should lock and expire all default database user accounts. Oracle Database provides SQL 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 are 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 utilizing Database Configuration Assistant.
If any default database server user account other the ones left open is required for any reason, a database administrator (DBA) need simply unlock and activate that account with a new, meaningful password.
Enterprise Manager Accounts
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: then 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).
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.
Oracle Database 10g installation 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, meaningful, and distinct passwords to these administrative accounts. If Database Configuration Assistant is used, 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.
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 password MDSYS).
If any of the default user accounts that were locked and expired upon installation need to be activated, assign a new meaningful password to each such user account.
Even though Oracle does not explicitly mandate changing the default password for user SCOTT, Oracle nevertheless recommends that this user account also be locked in a production environment.
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, utilizing 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.
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 this parameter is not set to the value recommended earlier, 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 requires view access to the data dictionary, it is permissible to grant that user the SELECT ANY DICTIONARY system privilege.
Do not provide database users more privileges than are necessary. In other words, principle of least privilege is that a user be given only those privileges that are actually required to efficiently and succinctly perform his or her job.
To implement least privilege, restrict: 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 as much as possible. For example, there is generally no need to grant CREATE ANY TABLE to any non DBA-privileged user.
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 that may permit a minimally privileged user to access and execute packages that he may not directly be permitted to access. The more powerful packages that may potentially be misused are listed in the following table:
| Package | Description |
|---|---|
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This package permits arbitrary mail messages to be sent from one arbitrary user to another arbitrary user. Granting this package to |
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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. |
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This package allows the database server to request and retrieve data using HTTP. Granting this package to |
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If configured improperly, 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 |
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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. |
| 1 These packages should be revoked from PUBLIC and made executable for an application only when absolutely necessary. |
These packages are extremely useful to some applications that need them. They require proper configuration and usage for safe and secure operation, and may not be suitable for most applications.
Roles (groups of privileges) are useful for quickly and easily granting permissions to users. If your application users do not need all the privileges encompassed by an existing role, then create your own roles containing only the appropriate privileges for your requirements. Similary, ensure that roles contain only the privileges that reflect job responsibility.
For example, grant users the CREATE SESSION privilege to authorize them to log in to the database, rather than granting them the CONNECT role, which has many additional privileges. Unless users require all the extra privileges contained in the CONNECT role (or any other role), assign them individually only the minimum set of individual privileges truly needed. Alternatively, create your own roles and assign only needed privileges.
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, since 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.
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');
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, in general, 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.
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:
This recommendation applies to all types of files: data files, log files, trace files, external tables, bfiles, and so on.
Keep the database server behind a firewall. Oracle Database's 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 Network Associates' Gauntlet and Axent's Raptor. Supported packet-filtered firewalls include Cisco's PIX Firewall and supported stateful inspection firewalls (more sophisticated packet-filtered firewalls) include CheckPoint's Firewall-1.
If Oracle Database is behind a firewall, do not, under any circumstances, poke a hole through the firewall; for example, do not leave open Oracle Listener's 1521 port to make a connection to the Internet or vice versa.
Doing so 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 database(s) behind the firewall. Furthermore, an Oracle Listener running without an established password may be probed for critical details about the database(s) on which it is listening such as trace and logging information, banner information and database descriptors and service names.
Such a plethora of information and the availability of an ill-configured firewall will provide an attacker ample opportunity to launch malicious attacks on the target database(s).
Because the listener acts as the database's gateway to the network, it is important to limit the consequences of malicious interference:
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).
Sample configuration:
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)))
i. Prevent on-line administration by requiring the administrator to have write privileges on the LISTENER.ORA file and the listener's 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:
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 client computer's LISTENER.ORA file. For example, to access listener USER281 remotely., using the following configuration:)
user281 = (DESCRIPTION = (ADDRESS = (PROTOCOL = tcps) (HOST = ed-pdsun1.us.oracle.com) (PORT = 8281)) ) )
iii. Always establish a meaningful, well-formed password for the Oracle Listener to prevent remote configuration of the Oracle Listener. Password protect the listener:
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
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:
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.
Utilize 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 two parameters respectively deny or allow specific client IP addresses from making connections to the Oracle Listener (and thereby preventing potential Denial of Service attacks).
If possible, utilize Oracle Advanced Security to encrypt network traffic between clients, databases, and application servers. (Note that Oracle Advanced Security is available only with the Enterprise Edition of the Oracle database. It installs in Typical Installation mode and can be configured, after licensing, with the Oracle Net Manager tool or by manually setting six sqlnet.ora parameters to enable network encryption. )
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.
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 thereof.
Periodically check the security site on Oracle Technology Network for details on security alerts released by Oracle Corporation.
http://otn.oracle.com/deploy/security/alerts.htm
Also check Oracle Worldwide Support Service's site, Metalink, for details on available and upcoming security-related patches.
http://metalink.oracle.com
In summary, 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 those threats and the consequences of a successful breach of security. Also monitor and audit to detect either increased threat levels or successful penetration.
If you believe that you have found a security vulnerability in Oracle Database, 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
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