Chapter 4: Communication and Network Security Flashcards
-mulithomed firewall
Multi-homed firewalls may be used to setup a DMZ with a single firewall. (see next slide)
On any multi-homed machine, IP forwarding should be disabled.*
802.11 wireless protocols
802.11a 54Mbps5Ghz8 channels802.11b11Mbs2.4Ghz (same as other home devices)802.11g54Mbs2.4Ghz802.11i : Wireless with security. First standard to require WPAII802.11n100Mbs2.4Ghz or 5Ghz
802.15
Bluetooth
802.1x and eap
802.1x is a port based network access control and includes
EAP.
- EAP is an auth frameworks that describes many specific auth protocols PORT Based Auth. at Layer 2 for both wired and wireless
ad-hoc and infrastructure wireless
ah-hoc wirles cards to wireless cares infrastrcute is through access points
Application Proxies - Firewallpros & cons?
Like circuit layer proxies, but actually understand the application/protocol they are proxying.This allows for additional security as they can inspect the data for protocol violations or content.AdvantagesApplication proxies understand the protocol, so they can add extra securityCan have advanced logging/auditing and access control featuresEx. Restrict users to only allowed websitesEx. Inspect data for protocol violationsEx. Inspect data for malware (viri etc)DisadvantagesExtra processing requires extra CPU (slower)Proxies ONLY understand the protocols they were written to understand. So you generally have a separate application proxy for EACH protocol you want to proxyexamples: smtp proxies, ftp proxies
ARP
I’m looking for 192.168.1.2’s MAC addressanswer: that’s me at 00:af:14:b3:bc:12
Layer 2 take ip from L3 for the test say layer 2
Map IP address to Mac address via broadcast
it it then added to the ARP cache
arp poisoning: change mac address to bad server…
asymmetric dsl
fast download less upload
autonomous network how many entitites
one
Blue Bugging
More serious
Allows full use of phone
Allows one to make calls
Can eavesdrop on calls
Blue Jacking
sending spam to bluetooth devices
Blue Snarfing
Copies info off remote devices
Bonk
similar to Teardrop manipulates how a pc reassembles a packet and allows of too large a packet
Buffer Overflow
Attacks a specific type of memeory on a system …the buffers best avoided with input validation. too much to handle…
CHAP
does not expose the cleartext password and is not susceptible to replay attacks. CHAP relies on a shared secret: the password. The password is securely created (such as during account enrollment) and stored on the CHAP server. Since both the user and the CHAP server share a secret (the plaintext password), they can use that secret to securely authenticate.
circuit Switching
all data follows same pathPSTNISDNDSLT-carriers
Data Diddling
Altering/Manipulating data, usually before entry
DCE
similar to kerberos developed by Open Group The Distributed Computing Environment (DCE) is a software system developed in the early 1990s by a consortium that included Apollo Computer (later part of Hewlett-Packard), IBM, Digital Equipment Corporation, and others. The DCE supplies a framework and toolkit for developing client/server applications.
DDos
use of Control Machines (Handlers) and Zombies (Bots) many machines making the attack
Dial up protocol
PPP Point to Point Protocol: Provides Layer 2 framing for dial-up. Needs other protocols for securityEncryption: MPPEAuthentication:PAP (Password Authentication Protocol): Clear TextCHAP (Challenge Handshake Authentication Protocol) Client responds to a challenge from the server. The only way the client can answer correctly is if the correct password had been entered.EAP (Extensible Authentication Protocol) Extends capabilities beyond passwords (smart cards, biometrics, token devices, etc)
DMZ
A buffer zone between an unprotected network and a protected network that allows for the monitoring and regulation of traffic between the two.
DNS port
UDP port 53 tcp port 53 large answers ie zone xfer
Dos
Denial of Service - overwhelm a system and disrupt its availability
DSL
layer 1
Dynamic Packet Filtering Firewalls
Like a state full firewall but more advanced. Can actually rewrite rules dynamically.Some protocols such as FTP have complex communications that require multiple ports and protocols for a specific application, packet and statefull filter cannot handle these easily, however dynamic packet filter can as they can create rules on the fly as needed.
Ethernet
Layer 2 transports data via frames
Ethernet
Most common form of LAN networking, has the following characteristicsShares mediaBroadcast and collision domains (see next slides)CSMA/CDSupports full duplex with a switchDefined by IEEE 802.3
Fraggle
Similar to smurf but uses UDP vs IMCP layer 4 attack. you can block distrubed attacks on router to mitigate.
frame relay
Frame Relay is a packet-switched Layer 2 WAN protocol that provides no error recovery and focuses on speed. Higher-layer protocols carried by Frame Relay, such as TCP/ IP, can be used to provide reliability. Frame Relay multiplexes multiple logical connections over a single physical connection to create Virtual Circuits; this shared bandwidth model is an alternative to dedicated circuits such as T1s. A PVC (Permanent Virtual Circuit) is always connected, analogous to a real dedicated circuit like a T1. A Switched Virtual Circuit (SVC)
FTP
uses tcp to guarantee delivery
vs
tftp uses udp faster doesn’t guanatee delivery.
http
port 80
https port
443
imap port
internet massage access protocol port 143
imcp
L3 used to troubleshoot and report error conditions
ICMP – “IP helper”Protocol behind echoing utilities like PING and Traceroute
Frequently exploited
- LOKI :sending data in ICMP messages header (not supposed to be there) —covert Channel
- Ping of Death:violates the MTU (maximum transmission unit) size
- Ping Floods: Lots of ping traffic
- SMURF: Uses spoofed source address (Target) and directed broadcasts to launch a DDos
infrastructure as a service
storing things in the cloud. services provided by the cloud vs local…
IPsec
IPv4 has no built-in confidentiality; higher-layer protocols such as TLS are used to provide security. To address this lack of security at Layer 3, IPsec (Internet Protocol Security) was designed to provide confidentiality, integrity, and authentication via encryption for both IPv4 and IPv6. IPsec is a suite of protocols; the major two are Encapsulating Security Protocol (ESP) and auth header AH
IPv4
32 bit source and destination address
IPv6
64 bit destination address
ISDN
PRI and BRI
L2TP
Layer 2 Tunneling ProtocolCisco designed L2F to break free of dependence on IP networks, but kept it proprietary.L2TP was a combination of L2F and PPTPDesigned to be implemented in software solutionsTHERE IS NO SECURITY with L2TP. It MUST use IPSec to secure
L3 Firewall
Static Packet Filters: Base decisions on Source/Destination IP address and port
L5 Firewall
Stateful Inspection Knowledge of who initiated the session. Can block unsolicited replies. Protocol Anomaly firewalls.
L7 Firewall
Application Proxies/Kernel Proxies: Make decisions on Content, Active Directory Integration, Certs, time…etc
Land Attack
Creates a “circular reference” on a machine. Sends a packet where source and destination are the same.
Layer 1 Threats
Physical - TheftUnauthorized AccessVandalismSniffingInterferenceData Emanation
Layer 2 two sub layers
Data Layer —– sublayers are: MAC Media Access Control xfters data down to phys layer & Logical Link Control up to L3. -Error Dectectiondevices: switches and bridgesEthernet card and its mac addresss
Layer 3
network layer describes routing moving data from a system on one lan to a system on another. IP address and routers ICMPOther protocols that “work” on this layer are: ICMP – IP “helpers” (like ping) IGMP – Internet Group Message Protocol IPRouters All protocols that start with “I” (except IMAP) Ping Floods, Pings of Death, Loki, Smurf
Layer 4
OSI Layer 4 Transport – Provides end-to-end data transport services and establishes a logical connection between 2 computers systems
”The “pony express”
Protocols used at layer 4:
- SSL/TLS (Discussed in Cryptography Chapter)
- TCP UDPTCP &
- UDP and L4 protocols SSL/TLS
Layer 5
OSI Layer 5 (Session) – responsible for establishing a connection between two APPLICATIONS! (either on the same computer or two different computers)
- Create connection
- Transfer data
- Release connection
TCP - Does session oriented services
.Session layer manages sessions which provide maintenance on connections. connections between applications RPC’s , simplex 1/2 duplex, full duplex
setup, maintainance and teardown of session
Layer 6
OSI Layer 6 Presentation Layer – presents the data in a format that all computers can understand
Think 3 things: Formating, Compression and Encryption
testable - This is the only layer of OSI that does NOT have any protocol.
- Concerned with encryption, compression and formatting
Making sure data is presented in a universal format
File level encryption
Removing redundancy from files (compression)
Presentation Layer - presents data to the application concepts include data conversion, ASCII and image formats gif, jpeg, tiff
Layer 7
APPLICATION Layer
This defines a protocol (way of sending data) that two different programs or applications understand.
- HTTP, HTTPS, FTP, TFTP, SMTP, SNMP, etc.
- Application Proxies
- Non-Repudiation
- Certificates
- Integration with Directory SErvices
- Time awareness.
- Application- web brower, word processor etc.Procy Firewalls
- Content Inspection
if you don’t know what application try layer 7 cause there’s a bunch!
LEAP
lightweight extensible auth protocol cisco proprietary has security flaws