Domain 4 - Communication and Network Security Flashcards
Virtual extensible LAN (VXLAN)
network virtualization enabling high scale segmentation, can make MILLIONS versus just 4096 VLANS, tunneling protocol that encapsulates an ethernet frame (layer 2) in a UDP packet, layer 2 can typically only be attacked from within ie MAC spoofing or flooding, RFC 7348 is the vxlan rfc
Software defined networks (SDN)
enables network to be centrally controlled using software, can reprogram the data plane at any time, SD-LAN and SD-WAN, typically uses ABAC!! separate control plane from data plane and create sec challenges, vulns include man in the middle attacks and DoS, secure with TLS!
SDWAN
enables users in branch offices to remotely connect to an enterprises network, enables use of many network services MPLS, LTE, broadband, etc. Sec is based largely on VPN tunnels, Ipsec, next gen firewalls (NGFWs), and micro-segmentation of application traffic, uses secure access service edge (SASE) to decentralize connectivity
Li-Fi
uses LED to transmit data, can function in areas susceptible to electromagnetic interference, can theoretically transmit up to 100gbit/s, only requires working LEDs but walls are a barrier, still in development
Zigbee
short range wireless personal area network (PAN), supports automation/ machine to machine comms/ remote control/ monitoring of IOT devices, supports centralized/ distributed models and mesh topology, assumes that symmetric keys used are transmitted securely (encrypted in transit), IOT smart home hubs
5G
faster speed lower latency, doesn’t identify users through SIM cards = can assign identity through device, standalone (SA) version of 5G will be more secure than non-standalone (NSA) version, anchors control signaling of 5G networks to the 4G core, Diameter protocol provides authentication/ authorization/ accounting (AAA), DDoS is a concern due to scale of IoT endpoints
Content delivery networks (CDN)
geographically distributed network of proxy servers and their data centers, goal is fast and highly available content delivery by distributing content spatially relative (close to) users, CDN networks serving Javascript have been targeted to inject malicious content into pages, vendors in CDN space offer DDoS protection and web application firewalls (WAFs), video/ audio streaming
The OSI MODEL
All People Seem To Need Data Processing
Physical (layer 1 OSI)
contains device drivers that tell the protocol how to use the hardware for tramission/ reception of bits. 802.11 - Wifi, ethernet, bluetooth, EIATIA-232, EIA/TIA-449, X21, HSSI, SONET
Data Link (layer 2 OSI)
- Frames!! are the transmission type, formatting packet from Network layer in proper format for transmission, ARP, PPP, L2F, L2TP, PPTP, FDDI, ISDN, SLIP
Network (layer 3 OSI)
- PACKETS!! routing and addressing information (source and destination) ICMP, IP, IPSec, NAT, SKIP, IPX, RIP, OSPF, IGMP
Transport (layer 4 OSI)
- manages integrity of a connection and controlling the session (segment or diagram), TLS, TCP, UDP, SPX, SSL
Session (layer 5 OSI)
- establishing/ maintining/ terminating communication sessions between computers, SMB, RPC, NFS, SQL
Presentation (layer 6 OSI)
- transforms data received from application layer into a format that any system following the model can understand, encryption protocols and format types such as ASCII, EBCDICM, TIFF, JPEG, MPEG, MIDI
Application (layer 7 OSI)
- interfacing user applications, network services, or the OS with the protocol stack, HTTP, SSH, FTP, SMTP, POP3, IMAP, SNMP, SET, telnet
TCP/IP stack vs OSI
Application = Application/presentation/session
Transport = Transport
Internet = Network
Link = Datalink / Physical
Common ports
FTP = TCP 20/21
SSH = TCP 22
Telnet = TCP 23
SMTP = TCP 25
DNS = TCP/UDP 53
DHCP = UDP 67/68
TFTP = UDP 69
HTTP = TCP 80
Kerberos = TCP/UDP 88
POP3 = TCP 110
NTP = UDP 123
NetBIOS = TCP/UDP 137/138/139
iMAP = TCP 143
SNMP = TCP/UDP 161/162
BGP = TCP 179
Syslog = UDP 514
LDAP = TCP 636
FTP over TLS = TCP 989/990
TCP
connection oriented, byte stream= every byte matters, does NOT support multicasting/ broadcasting, supports full duplex transmission, reliable service of data transmission, packet is called a segment , provides error detection
UDP
connection-less protocol, message stream, supports multi-casting and broadcasting, NO support for full duplex (simultaneouse bidirectional), unreliable service of data transmission, packet is called a datagram, no support for error detection, media streaming!!
Cabling types
CAT 5 = 100mb
CAT 5e = 1gb
CAT 6 = 10gb 55meters
CAT6e = 10gb 55meters
CAT7 = 10gb 100 meters
Star (network topology)
- central connection device (can be hub or switch), each system is connected to central hub by a dedicated segment, MODERN ETHERNET
Mesh (network topology)
connects systems to all other systems using numerous paths, partial mesh connects many systems to many other systems, redundant connections allow for multiple segment failures
Ring (network topology)
connects each system as points on a circle, connection medium acts as a unidirectional transmission loop, only one system can transmit data at a time, traffic management is performed by a token, token ring is a ring based network, “collision avoidance”
Bus (network topology)
connects each system to a trunk, all systems on a bus can transmit simultaneously which can result in collisions (when 2 systems transmit data at the same time and signals interfere)
Analog
continuous signal that varies in frequency/ amplitude/ phase etc. variances in continuos signal produce a wave shape as opposed to square shape of digital, comms become altered and corrupted because of attenuation over long distances
Digital
comms occur through electrical signal and state change (0s and 1s), more reliable over distance or when interference is present, uses current voltage that creates binary data
Synchronous
comms rely on timing or clocking mechanism, high rates of data transfer, i.e. networking
Asynchronous
comms rely on a stop and start delimiter bit to manage transmission of data, small amounts of data, i.e. public switched telephone network (PSTN)
Baseband
single comm channel, form of digital signal, direct current applied to cable. i.e. ETHERNET
Broadband
supports multiple simultaneous signals, suitable for high throughput and multiplexing several channels, form of ANALOG signal. Ie TV, cable modem, ISDN, DSL, T1, T3
Broadcast,Multicast,Unicast
determine how many destinations a single transmission can reach. Broadcast=all possible, Multicast=multiple specific recipients ie windows OS deployment, Unicast=single communication to specific recipient
Carrier sense multiple access (CSMA)
- decreases chances of collisions when 2 or more stations start sending signals over datalink layer.
-Each state must check the state of the medium.
-CSMA/CA=collision avoidance=grants single comm at any given time ie ring networks with token/ wireless/ used in 802.11 standard,
-CSMA/CD=collision detection=responds to collisions by having each member of the collision domain wait for a short but random period of time before restarting process the resends data frame ie wired networks/ 802.3 standard
Token passing
performs comms using digital token, releases token once transmission is complete, prevents collisions in ring networks
Polling
performs comms using master-slave config, primary system polls the secondary system in turn when they have to transmit data, used by synchronous datalink control (SDLC)
Network segmentation
boosts performance, dedicated environment to reduce comm problems, security via isolating traffic
Intranet
private network
Extranet
sectioned off portion of network to act as intranet for private network, but also serves information to public internet
DMZ
extranet for public consumption aka perimeter network
Bluetooth (IEEE 802.15)
- connects wireless devices, connections are paired with 2.4ghz radio, often a 4 digit code to pair
Bluejacking
pushing unsolicted messages to nearby bluetooth users, more of an annoyance
Bluesnarfing
- data theft, wirelessly connecting to some early BT enabled mobile devices without owners knowledge to download data
Bluebugging
grants hackers remote control over the feature and functions of a BT device
Wi-Fi versions (latest 802.11)
802.11n = 200+ mb/s > 2.4ghz
802.11ac = 1gb/s > 5ghz
SSID broadcast
- wireless networks announces SSID on regular basis with a beacon frame, any device can try to connect, hiding SSID is considered “security through obscurity”
Temporal key integrity protocol/ WPA (TKIP)
- commonly known as WPA, was designed as replacement for WEP without need to replace legacy hardware
CCMP
- used with WPA2, counter mode with cipher block chaining message authentication code protocol, created to replace WEP and TKIP/WPA, uses AES with 128bit