As we know, we are fighting an asymmetrical battle with attackers when it comes to defend our valuable artifacts such as databases, web servers, mail servers, etc. Also, I am not aware of any system that is free of vulnerabilities. Attackers exploit those vulnerabilities to gain access to these systems. Further, you cannot eliminate the human factor. No amount of technology can make a system secure if your users are attack vectors. The reality is that we cannot make any system completely secure.
So, I hear you ask if we cannot secure our systems, aren't we doomed to fail? Not really. Having been working in the security field for a long time, one thing I have realized is that security is not about building 100% secure systems, but rather it is about building systems that makes attackers life harder to break in. Security is all about economics. If you can make the system harder to break in, financially motivated attackers will give up eventually as the effort (aka investment on time and resources) they put in is far greater than the outcome (aka profit by breaking in) they get.
So, if we cannot build fully secure systems, how can we make systems harder to break in? You have to deploy multiple layers of security in order to protect your valuable assets. In other words, you need to build defense in depth into your system. Think about a bank safe. The safe is not kept in a public area, but rather you have to go through multiple doors to get into where the safe is mounted. Once you reach there, then you are left with the task of breaking the safe itself. That's a lot of labor. Most attackers would simply give up.
Let me show how Oracle database 12c takes the defense in depth approach.
- Strong authentication (preventive)
- On the wire encryption (preventive)
- AVDF - Audit Vault and Database Firewall (preventive and detective)
- Secure backup
- Data masking
- Data redaction (for applications)
- DAC and RBAC based privileges and roles
- VPD (Virtual Private Database) - row level access control
- OLS (Oracle Label Security) - multi-level security
- DV (Database Vault) - privileged user controls
- RAS (Real Application Security) - middleware-application security
Data at rest:
- Standard ACID controls
- TDE (Transparent Data Encryption) - data-at-rest encryption
- Oracle wallet/OKV (Oracle Key Vault) for key management
Administrative/Hardening Tools - help reduce the attack surface:
- Secure configuration management
- Privilege analysis
- Sensitive data discovery
- Unified auditing framework
- AVDF (Audit Vault)
Similar to the bank safe example mentioned above, it is also very important to harden the environment (OS, network) where the database is deployed as well.