Transcript Security - Department of Computer and Information Science

Department of Computer and Information Science,
School of Science, IUPUI
Oracle Security
Dale Roberts, Lecturer
Computer Science, IUPUI
E-mail: [email protected]
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Where Is Security Enforced?
Application
Applications often have the need to be security-aware.
Some commercial applications use the One Big Application user
model. The SQL that users submit is restricted by the application.
Are application users also database users. (Does the application
have a user table?) What user is used to connect to Oracle?
Applications whose users are not database users have no choice but
to manage security themselves.
Security best practices recommend authenticating the user with the
database, not using a shared applid. Sharing an applid compromises
security because the identity of the user is unknown to the database
Ad-hoc tools like SQLPlus, Access, Excel or Toad do not restrict the
SQL and bypass application security.
Universal implementation of security requires that every application
module correctly implement security – difficult and expensive.
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Where Is Security Enforced?
Database
Applications whose users are also database users can
choose to implement application or database security.
Database security cannot be bypassed, even with ad hoc
tools.
Oracle audit features can record who does what inside
the database.
Database roles can be set up for different classes of
users, allowing and restricting access as appropriate.
Database roles can be derived from enterprise roles
maintained outside of Oracle (LDAP with Oracle Identity
Management), reducing administrative burden.
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Basic Oracle Security
By What Authority?
Users
Roles
Grant and revoke
Synonyms
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CREATE USER
CREATE USER
Create user username identified by password;
Create user username identified externally;
Changing passwords
Alter user username identified by password;
Password Management – determined by DBA created profiles.
Password lifetime
Grace period
Account lock rules
Password reuse rules
Moving to another user, connect sqlplus command
CONNECT
CONNECT username
CONNECT username / password
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Password Management
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;
ALTER USER johndoe ACCOUNT
UNLOCK;
CREATE USER jbrown
IDENTIFIED BY zX83yT ...
PASSWORD EXPIRE;
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CREATE ROLE
Roles manage sets of privileges.
CREATE ROLE
Create role rolename;
Standard Oracle Roles
CONNECT – connect to database and perform very limited functions.
RESOURCE – for basic users.
DBA – all system privileges.
Maximum roles allowed is set at startup,
max_enabled_roles parameter (30 on phoenix).
Roles can have passwords, but do not by default.
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Role-based Security Model
Roles are a named set
of privileges
Resolves delete
anomolies like
dropping a user
loosing all the
security rules.
Users are never
directly assigned
privileges.
More than one role
can be active.
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GRANT and REVOKE
Grant for object privileges
GRANT {privilege, … | ALL} [ (column,…) ]
on object to {user | role}
[with grant option]
[with hierarchy option];
Grant for system privileges
GRANT {system privilege | role | ALL}
to {user | role} [, {user | role}, …]
[identified by password]
[with admin option];
Revoke takes privileges from roles or users.
REVOKE {system privilege | role | ALL}
[, {system privilege | role | ALL} …]
from {user | role} [, {user | role}, …];
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Synonyms, Examples, Other
What you can grant to other users
Tables: alter, references, index, on commit refresh, query rewrite, all
PL/SQL Procedures and Functions: execute
Sequences: select, alter
Synonyms provide for another name for an object. (location independence)
CREATE [PUBLIC] SYNONYM synonym FOR SCHEMA.OBJECT[@LINK];
Examples:
CREATE ROLE MYTEAM;
GRANT MYTEAM TO JOE, TOM, SUE;
GRANT SELECT ON MYTABLE TO MYTEAM;
GRANT UPDATE (COL1) ON MYTABLE TO MYTEAM;
CREATE PUBLIC SYNONYM TAB1 FOR MYSCHEMA.MYTABLE;
Advanced Options for Security by User
Virtual private database (VPD) adds a where clause to all commands issued by the user to restrict
data to only his view of the database.
Oracle Label Security uses security labels on all rows, users only have access to those in their
hierarchy.
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Enterprise-level Considerations
Application access is strictly enforced using roles.
Roles are defined based on function, not operation. For example, a
role APPL_USER_WRITE_ROLE means that the user can modify
application data. The role may include SELECT, EXECUTE grants
as well as INSERT, UPDATE, DELETE.
Role APPL_USER_READONLY_ROLE may also include some
INSERT/UPDATE privileges to activity logs, etc., but the user cannot
modify application data.
Public synonyms cannot be used when there is more than one
instance of an application in a database instance. This often
happens for test environments: string, integration, user acceptance,
capacity, etc.
Batch jobs also require roles, such as APPL_BATCH_WRITE_ROLE.
Under no circumstances should any user or job ever login as the
schema owner.
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Advanced Security – VPDs
Virtual Private Databases - VPDs
VPDs are an advanced security topic that requires fluency in several
different areas including contexts, packages, triggers and SQL.
The grants discussed previously control access at an object-level.
You can grant SELECT to a VIEW as an example.
VPD implements what is called fine-grained access control. Finegrained access control means that security is implemented at a rowlevel. For example, the following query
SELECT * FROM emp;
can be changed by a VPD security policy to add a predicate
SELECT * FROM emp WHERE division = 'RETAIL';
VPD can also be set up to add predicates based on what columns
are mentioned.
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Acknowledgements
Loney, Oracle Database 10g The Complete Reference
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