SEC835

1. SEC835 Practical aspects of security implementation Part 1

2. Apply security services • Databases security • Email security

3. STRIDE • Spoofing • Any person or technology (Actor) component can be spoofed • Tampering • Data, or source code, or configuration parameters can be tampered • Repudiation • A user’s actions can be repudiated • Information disclosure • Data, or any other information including system architectural design, are vulnerable to information disclosure • Denial of Service • Any technology resource is vulnerable to DoS • Elevation of Privileges • Any user or technology related level of privileges is vulnerable to elevation of privileges

4. Databases • Spoofing: • DBA • ODBC driver • Tampering • Data • Configuration parameters • Information disclosure • Data • DB structure • ODBC credentials • Denial of service • RDB as the technology resource • Elevation of privileges • DBA • RPC

5. DB security • Strong access control • Database • Tables • Columns • In most cases RBAC has been implemented • SQL language allow runtime granting of access privileges to users or roles

6. DB security • The GRANT command: • GRANT {privileges/role} • [ON table] • TO {user/role/public} • [IDENTIFIED BY password] • [WITH GRANT OPTION] • The command allows granting of privileges and/or roles to another user or to another role thus providing a lot of flexibility in runtime privileges management

7. DB security • What to GRANT? • Select – grantee is allowed to read entire DB, table, or columns • Insert – grantee may insert rows in a table, or insert rows with values for specific columns in a table • Update – similar to insert • Delete – delete rows from a table • References – grantee is allowed to define foreign keys in another table that refer to the specified columns

8. DB security • REVOKE {privileges/ role} • [ON table] • FROM {user/role/public}

9. DB security • Cascading authorization • Allow a user granting access to another user, and so on • Revoke assumes cascading revoking of access • Be aware about security issues: • May be exploited to elevate privileges • Complicated grant schema may confuse revoking, leaving a user with the access granted

10. DB security • Tampering and Information Disclosure • Discrete storing • Store sensitive data only when it is really necessary • Encryption • Symmetric encryption for confidentiality • Hash for integrity • Strong encryption • Secure key management

11. DB encryption • Encryption may apply to • The whole table • The attribute (column) • The field (just a single cell) • Encryption makes a negative impact on the DB searching when encrypted values must be used as searching criteria • To help, the table partitioning may apply, where each partition has the unique index used to identify the range of records

12. DB encryption • Table partitioning example • Employee salary is a searching criteria but must be encrypted • The table partitioning is supported by the index that is mapped to the range of rows, e.g.: • 1 – values from 35K to 75K • 2 – values from 76 K to 95 K • 3 – values from 96 and up • The table rows contain encrypted values and indices that replace real values

13. DB encryption (cont.) • To decrypt the table that was encrypted and partitioned the map of indices and the ranges is required in addition to encryption keys • This map must be stored on the client, not on the server • Decryption and converting data into its original value also has been performed on the client • Make sure that encryption key on client side is safe

14. DBMS technology components • Must be protected from DoS attack • Strong access control for all type of interfaces: • Users • Admins • API • Bulk data loading • Strong data input validation • Protect against SQL injection attacks

15. DB backups DB must be regularly backups Media – tapes, or mirror servers, or both Backups must be stored at different (remote) location

16. DB backups • Mode of backups: • Full backup • Incremental – backup files changed after last backup • Differential – backup any file that are changed since the last full backup

17. Records retention • Policy exists to specify the period of keepng data available • Secure destruction • Shredding • Magnetic destruction

18. DB Security • Inference problem • A possibility to derive additional information from small pieces or fraction of data • Fractions or pieces can be not confidential but derived data is • Often may be completed by combining queries • Protection: • Splitting tables and assigning fine-grained access control • Separation of duties • Perturbation of data

19. DB security • Privacy issue • For some databases, in particular for healthcare and financial data, personal identifiers must not be present in the records • Achieved by applying data sanitization service • That is about applying the algorithms of “masking” data in store, or in a user’s view • That is in addition to cryptography

20. Secure Email • Major threats • Unauthorized access (confidentiality, integrity) • Viruses sent with attachments • Spam • Spoofing email addresses

21. Protection • Encryption • PGP – encryption technology used to protect confidentiality, integrity and authenticate a sender. This is a hybrid technology. The following is in use: • Public/private key (RSA) • Secret key for symmetric encryption (AES, 3DES) • Digital signature (MD5, SHA-1)

22. Protection • ANTI-virus protection • Install and keep up-to-date • Spam • Anti-spam software