CompTIA Security+ (SY0-601) : Securing Networks

Radio Frequency Interference:
A disturbance that can affect electrical circuits, devices, and cables due to AM/FM transmissions or cell towers

RFI causes more problems for wireless networks

Occurs when a signal transmitted on one copper wire creates an undesired effect on another wire

UTP is commonly used more often than STP

The electromagnetic field generated by a network cable or device when transmitting

A Faraday cage can be installed to prevent a room from emanating

Split the wires of a twisted-pair connection

Protected Distribution System:
Secured system of cable management to ensure that the wired network remains free from eavesdropping, tapping, data emanations, and other threats

Service Set Identifier:
Uniquely identifies the network and is the name of the WAP used by the clients
Disable the SSID broadcast in the exam

An unauthorized WAP or Wireless Router that allows access to the secure network

A rogue, counterfeit, and unauthorized WAP with the same SSID as your valid one

Same encryption key is used by the access point and the client

Wired Equivalent Privacy:
Original 802.11 wireless security standard that claims to be as secure as a wired network

WEP’s weakness is its 24-bit IV (Initialization Vector)

Wifi Protected Access:
Replacement for WEP which uses TKIP, Message Integrity Check (MIC), and RC4 encryption

WPA was flawed, so it was replaced by WPA2

802.11i standard to provide better wireless security featuring AES with a 128-bit key, CCMP, and integrity checking

WPA2 is considered the best wireless encryption available

Wifi Protected Setup:
Automated encryption setup for wireless networks at a push of a button, but is severely flawed and vulnerable

Always disable WPS

Intentional radio frequency interference targeting your wireless network to cause a denial of service condition

Wireless site survey software and spectrum analyzers can help identify jamming and interference

Creates network segment for each client when it connects to prevent them from communicating with other clients on the network

Act of searching for wireless networks by driving around until you find them

Attackers can use wireless survey or open source attack tools

Act of physically drawing symbols in public places to denote the open, closed, and protected networks in range

Occurs when an attacker observes the operation of a cipher being used with several different keys and finds a mathematical relationship between those keys to determine the clear text data

This happened with WEP and makes it easy to crack

Attack that targets an individual client connected to a network, forces it offline by deauthenticating it, and then captures the handshake when it reconnects

Used as part of an attack on WPA/WPA2

Occurs when an attacker continually guesses a password until the correct one is found

Brute force will always find the password…eventually!

Wi-Fi Protected Access 3 (WPA3) was introduced in 2018 to strengthen WPA2
WPA3 has an equivalent cryptographic strength of 192-bits in WPA3 - Enterprise Mode

Largest improvement in WPA3 is the removal of the Pre-Shared Key (PSK) exchange

WPA3 Personal:
Uses CCMP-128 as the minimum encryption required for secure connectivity

WPA3 Enterprise:
Uses AES-256 encryption with a SHA-384 hash for integrity checking

Simultaneous Authentication of Equals:
A secure password-based authentication and password-authenticated key agreement method

Simultaneous Authentication of Equals (SAE) provides forward secrecy

A feature of key agreement protocols (like SAE) that provides assurance that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised

The AP and the client use a public key system to generate a pair of long-term keys

The AP and the client exchange a one-time use session key using a secure algorithm like Diffie-Hellman

The AP sends the client messages and encrypts them using the session key created in Step 2

Client decrypts the messages received using the same one-time use session key

The process repeats for every message being sent, starting at Step 2 to ensure forward secrecy

Important document:
Defines purpose & scope
Makes everyone aware of test parameters

Type of testing & schedule:
Physical breach, internal test, external test
Working hours, after 6PM, etc

Rules:
IP address ranges
Emergency contacts
How to handle sensitive info

Uses SSL/TLS

No big VPN clients

No digital cert requirement or shared passwords

Unlike IPsec

Very small client or within browser

Web cryptography API as part of browser (no software)

Almost always on
Firewalls act as concentrators communicating with one another

L2TP
Connecting sites over layer 3 network as if they were connected at layer 2
Used in conjunction with IPsec for encryption
L2TP over IPsec

Defends the Layer 2 Spanning Tree Protocol (STP) topology against BPDU-related threats and is designed to protect the switching network

If a BPDU frame is seen on a PortFast configured interface, shutdown the device
Prevents looping

File Integrity Monitoring:
Some files change all the time
Some should never change
Monitor important OS & application files

Windows: SFC
Linux: Tripwire

Examines copy of traffic (port mirror or tap)
No way to block traffic
Out-of-Band Response
Copy of traffic is sent to IPS

If identified as malicious, IPS sends TCP RST (reset) frame
Prevents subsequent malicious requests (but not initial)

IDS/IPS sits physically inline (all traffic passes through)

In-Band Response
Malicious traffic is immediately identified
Dropped at the IPS (does not get through network)

Instances in a private subnet can connect to services outside your VPC, but external services cannot initiate a connection with those instances

Galois/Counter Mode Protocol
Stronger encryption than WPA2
AES Encryption
MIC uses GMAC

Occurs when a user is able to gain the rights of another user or administrator

Vertical Privilege Escalation = User to Admin
Horizontal Privilege Escalation = User to User