Database Security

1. Database Security John Ortiz

2. Secure Passwords • Two main requirements for choosing a secure password: • 1) MUST be easy to remember • 2) MUST be difficult to guess • Do NOT pick any of these types of passwords because they are easily guessed! • your name, spouse’s name, child’s name, pet’s name, friend’s name, fantasy character’s name, coworker’s name, ANYONE’S NAME Database Security

3. Secure Passwords (cont) • name of operating system or host computer • your license plate, SSAN, phone number • birth date, anniversary date, any significant date • information easily obtainable about you • any word out of any dictionary • a single word (in any foreign language) • a place • slang or profanity Database Security

4. Secure Passwords (cont) • Do NOT use any of these either! • Groupings of similar letters • patterns of letters on a keyboard such as ‘asdfgh’ or ‘qwerty’ • any of the previous spelled backwards • any of the above followed or preceded by a single digit Database Security

5. Secure Passwords • substituting similar numbers for letters: • 0 for O, 3 for e, etc. • substituting similar characters for letters: • @ for a, ! for I • adding numbers to anything crackable • tarot12, car9rot • using obscure words like ‘quamash’ Database Security

6. Secure Passwords (cont) • NEVER write down any secure password, since it will then no longer be secure • What is left? • Should be at least 8 characters, with one or more special characters (such as !, @, #, etc.), and one or more digits • first letter from each word in a line out of a favorite book or song • Example: Off We Go in 2 the Wild Blue Yonder (owg2wby) Database Security

7. Secure Passwords (cont) • groupings of unrelated words • Remember, a UNIX system only uses the first 8 characters to develop the encrypted password file! • Do NOT use any examples from here • Examples of CRACKED PASSWORDS • L0v3rs, br0nc0s, kaitlyn1 • Qwerty1, hoquiam5, nitwit1 Database Security

8. Security Mechanisms • Discretionary Security – grant privileges to users, including access to specific files, records, attributes, etc. • May have r, w, x, d specified separately • Mandatory Security – used to enforce multi-level security systems. Data is divided into classifications such that a user only has access to data at his/her classification or lower Database Security

9. Discretionary Mechanisms • Authorization Identifier – refers to a user account or group of accounts (login, password) • Two levels of privileges: • Account level – privileges each account holds independent of relations in DB • Relation level – control access to individual relations or views • SQL uses GRANT/REVOKE to assign privileges Database Security

10. GRANT Privileges • SQL allows the granting of the following types of privileges: • SELECT (retrieval) • MODIFY (update, delete, insert) • REFRENCE (reference specific relations when specifying integrity constraints) • Views allow very specific control over which attributes are visible to a particular user • Privileges can propagate from one user to another Database Security

11. REVOKE Privileges • SQL allows the suspension of previously granted privileges • If a privilege has propagated, and the owner account revokes it, all the propagated privileges will also be revoked • Remember, this is not exactly how Oracle implements this feature • If an account receives privileges from 2 or more sources, then the privileges are only revoked if all sources revoke them Database Security

12. Mandatory Access Control • Security Classes: • Top Secret – revelation may cause catastrophic damage to U.S. security • Secret – revelation may cause grave damage to U.S. security • Confidential – revelation may cause damage to U.S. security • Unclassified – read it in the newspaper Database Security

13. Mandatory Access Control (cont) • May read any data up to your level of classification • May write to any data at or above your classification (can NOT write to lower classification because it may contain higher level information) • In a relational database, attributes are given a classification level • In addition, the tuple itself is classified at the highest level of any of its attributes Database Security

14. Mandatory Access Control (cont) • An apparent key is the set of attributes that would have formed the PK in a regular DB • A multilevel relation will appear different to different users – some parts of the PK may be classified at a higher level • In some cases, tuples stored at a higher level can be downgraded and viewed at a lower level • In other cases, 2 sets of tuples may need to be stored • Interesting possibilities for Norm., CC & R, Consistency, etc. - EVERYTHING IS HARDER! Database Security

15. Multilevel Security • Entity Integrity – all attributes that are members of the apparent key must not be null and must have same security classification within each tuple • All other attributes must have classification greater than or equal to apparent key Database Security

16. Statistical Database Security • Protect access to individual data items, but not the aggregate results • Possible to infer individual data from some statistical queries (I.e. if the query limits the number of tuples to just a few) • Solutions: • Restrict queries that only access a few tuples • Restrict repeated access to same data set Database Security