Securing Networks Flashcards
RFI
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
Crosstalk
Occurs when a signal transmitted on one copper wire creates an undesired effect on another wire
UTP is commonly used more often than STP
Data Emanation
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
PDS
Protected Distribution System:
Secured system of cable management to ensure that the wired network remains free from eavesdropping, tapping, data emanations, and other threats
SSID
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
Rogue Access Point
An unauthorized WAP or Wireless Router that allows access to the secure network
Evil Twin
A rogue, counterfeit, and unauthorized WAP with the same SSID as your valid one
Pre-Shared Key
Same encryption key is used by the access point and the client
WEP
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)
WPA
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
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
WPS
Wifi Protected Setup:
Automated encryption setup for wireless networks at a push of a button, but is severely flawed and vulnerable
Always disable WPS
Wifi Jamming
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
AP Isolation
Creates network segment for each client when it connects to prevent them from communicating with other clients on the network
War Driving
Act of searching for wireless networks by driving around until you find them
Attackers can use wireless survey or open source attack tools
War Chalking
Act of physically drawing symbols in public places to denote the open, closed, and protected networks in range
IV Attack
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
Wifi Disassociation Attack
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
Brute Force Attack
Occurs when an attacker continually guesses a password until the correct one is found
Brute force will always find the password…eventually!
WPA3
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
WPA3: SAE
Simultaneous Authentication of Equals:
A secure password-based authentication and password-authenticated key agreement method
Simultaneous Authentication of Equals (SAE) provides forward secrecy
WPA3: Perfect Forward Secrecy (AKA: 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
Penetration Testing: Rules of Engagement
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
VPN: SSL VPN
Uses SSL/TLS No big VPN clients No digital cert requirement or shared passwords Unlike IPsec Very small client or within browser
VPN: HTML5 VPN
Web cryptography API as part of browser (no software)
VPN: Site-to-Site VPN
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
BPDU Guard
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
FIM
File Integrity Monitoring:
Some files change all the time
Some should never change
Monitor important OS & application files
Windows: SFC
Linux: Tripwire
Passive Monitoring
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)
Inline Monitoring
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)
NAT Gateway/VPC Gateway Endpoint
Instances in a private subnet can connect to services outside your VPC, but external services cannot initiate a connection with those instances
WPA3: GCMP Block Cipher Mode
Galois/Counter Mode Protocol
Stronger encryption than WPA2
AES Encryption
MIC uses GMAC
Privilege Escalation
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
