EC-Council CND Module 10: Data Security Exhaustive Study Notes

Module 10 – Data Security (Key Concepts Summary)

1. States of Data

Data at Rest:

Stored data that is not moving or being processed.

Examples: hard drives, databases, USB drives.

Data in Use:

Data currently being processed or stored in memory (RAM).

Data in Transit:

Data moving across a network.

Examples: emails, web traffic, file transfers.

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2. Authentication vs Authorization

Authentication:

Verifies a user's identity.

Question: Who are you?

Examples: password, fingerprint, OTP.

Authorization:

Determines what an authenticated user can do.

Question: What are you allowed to do?

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3. Access Control Models

MAC (Mandatory Access Control):

Permissions are controlled by the system.

Used in military and government environments.

DAC (Discretionary Access Control):

The owner of the resource decides who gets access.

RBAC (Role-Based Access Control):

Permissions are assigned based on job roles.

Rule-Based Access Control:

Access is granted or denied based on rules.

Example: allow access only during work hours.

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4. Data Encryption

Purpose:

Protect confidentiality by converting readable data into unreadable ciphertext.

Types of Data-at-Rest Encryption:

Disk Encryption:

Encrypts the entire storage device.

File-Level Encryption:

Encrypts specific files or folders.

Removable Media Encryption:

Encrypts USB drives and external storage.

Database Encryption:

Encrypts data stored inside databases.

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5. SSL, TLS, and HTTPS

SSL:

Older secure communication protocol.

TLS:

Modern replacement for SSL.

HTTPS:

HTTP + TLS.

Provides:

- Confidentiality

- Integrity

- Authentication

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6. Digital Certificates

Digital Certificate:

Electronic identity of a website.

Certificate Authority (CA):

Trusted organization that issues certificates.

Certificate Types:

DV (Domain Validation):

Verifies domain ownership only.

OV (Organization Validation):

Verifies domain and organization.

EV (Extended Validation):

Highest level of verification.

Certificate Renewal:

Extending a certificate before expiration.

Certificate Revocation:

Cancelling a certificate before expiration.

CRL (Certificate Revocation List):

List of revoked certificates.

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7. Data Masking

Purpose:

Hide sensitive data while keeping its format usable.

Types:

Static Data Masking:

Masks data in a copy of the database.

Dynamic Data Masking:

Masks data when displayed to users.

On-the-Fly Data Masking:

Masks data while being transferred between environments.

Common Masking Techniques:

- Character Scrambling

- Lookup Substitution

- Nulling Out

- Shuffling

- Number/Date Variance

- Masking Out

- Date Aging

- Pseudonymization

- Data Generalization

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8. Backup Methods

Hot Backup:

Performed while the system is running.

Advantage: immediate recovery.

Disadvantage: expensive.

Cold Backup:

Performed while the system is shut down.

Advantage: inexpensive.

Disadvantage: downtime required.

Warm Backup:

Combination of hot and cold backup.

Moderate cost and recovery speed.

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9. Backup Locations

Onsite Backup:

Stored at the same location as the original data.

Advantage: easy access.

Disadvantage: vulnerable to site disasters.

Offsite Backup:

Stored at a remote location.

Advantage: protection from local disasters.

Disadvantage: management complexity.

Cloud Backup:

Stored with a cloud provider.

Advantage: accessible anywhere.

Disadvantage: less direct control.

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10. Backup Types

Full Backup:

Copies all data.

Advantages:

- Fastest restore

Disadvantages:

- Slow backup

- Large storage requirement

Differential Backup:

Copies all changes since the last Full Backup.

Advantages:

- Faster than Full Backup

- Faster restore than Incremental

Disadvantages:

- Larger than Incremental

Incremental Backup:

Copies only changes since the last backup.

Advantages:

- Fastest backup

- Least storage required

Disadvantages:

- Slowest restore

Key Comparison:

Full Backup:

Copies everything.

Differential Backup:

Copies changes since the last Full Backup.

Incremental Backup:

Copies changes since the last Backup.

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11. Data Retention

Data Retention:

Keeping data for a required period based on business, legal, or compliance requirements.

Data Retention Policy:

Defines how long data must be kept and when it should be destroyed.

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12. Data Destruction

Purpose:

Permanently destroy data so it cannot be recovered.

Methods:

- Wiping

- Degaussing

- Shredding

- Crushing

- Physical Destruction

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13. Data Loss Prevention (DLP)

DLP:

A set of tools, policies, and processes used to prevent unauthorized data leakage.

Protects:

- Data at Rest

- Data in Use

- Data in Transit

Examples:

- Blocking USB copying

- Preventing sensitive email transmission

- Monitoring cloud uploads