Network Security Flashcards
Security Problems
-Remote Attacks
-Software Developed with ‘back doors’
-Insecure Configuration
-Internal attacks
-Access Control
-Attaching personal devices to work networks
Security Management
-Control and Distribution
-Event Logging
-Monitoring
-Parameter Management
Security Services
-Denial of Service Prevention
-Access control – what users can do when logged into the system
-User Authentication (Multi-factor,2FA)
-Data Confidentiality
-Accountability
Security Mechanisms
-Encryption/Decryption
-Message Authentication
-Password Policy
-Digital Signatures
-Access Control
Secure Sockets Layer/Transport Layer Security
Mechanisms are utilised whenever a web access screen indicates that you are going into a secure mode of operation. E.g. for transfer of credit card details.
Secure Sockets Layer/Transport Layer Security Encryption
Encryption key may vary from 40 bits to 128 bits. 256 bits are used for a stronger cipher.
Trusted certificates
The trusted certificates contains the owner’s public key, which is trusted because it is cryptographically signed by a trusted agency.
DES, Triple DES and AES Encryption
The Data Encryption Standard (DES) dates back to the mid-1970’s
-Its 56-bit key length is inadequate today (it can be broken in less than 24 hours)
Triple DES has a much longer effective key length
The more recent Advanced Encryption Standards (AES) provides
-Greater security e.g 128-256-bit length
-An internationally developed algorithm (from Belgium)
-A 128-bit block cipher (for efficient computer implementation)
Virtual Private Networks (VPN)
Private network that uses public network (usually Internet) to connect remote sites or users together. Instead using dedicated, real-world connection such as leased line, a VPN uses “virtual” connections.
VPN appears to be private but is not
- “Privacy” occurs due to encryption
- Then, encapsulation is in “routable IP packets”
Virtual Private Networks
An outsider might intercept packets, but cant:
-Read them
-Modify them without detection
-Impersonate expensive T1/E1 leased lines
Two typical uses of virtual Private Networks
Replacing expensive T1/E1 leased lines
Replacing Expensive T1/E1 Leased Lines
A virtual private network may be utilized to replace expensive T1/E1 lines
-Using the organisation’s intranet or the internet instead
However, this does not provide any assurances of timeliness of delivery
-Gets the usual best-efforts delivery of the intranet or internet
Usage of Radius Protocol
Remote Authentication Dial-in user Service (radius) provides
-Authentication, Authorization checking and accounting
-Uses Point-to-Point Protocol (PPP)
-Operates on port 1812
-Commonly used to facilitate roaming
-Can provide customizable login prompts
RADIUS Authentication and Authorization Flow
RADIUS Client - Access Request - Radius Server
RADIUS Client < Access Accept - Radius Server
RADIUS Client < Access Reject - Radius Server
RADIUS Client < Access Challenge - Radius Server
Uncontrolled Interconnection into the Internet
Easy to connect to internet, all it takes is a router and appropriate approval. However is not good idea.
