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Networking Lesson 11: Network Security
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Terms in this set (41)
Why do we need network security?
- routing, BGP
- Naming, DNS -> Reflection; Phishing
What is a "route highjack"?
Occurs when an AS advertises a prefix that it does not own
What is "reflection"?
A way of attacking DNS. It is a way of generating very large amounts of traffic targeted at a victim. DDoS can be done this way (but not only this way).
What is "phishing?
A way pf attacking DNS, whereby an attacker exploits the domain name system in an attempt to trick a user into revealing private information
Why is the Internet insecure?
The Internet's design is fundamentally insecure.
1. Designed for simplicity, security not a consideration.
2. "On by default". When a host is connected, it is reachable by default from any other host.
3. Hosts are insecure.
4. Attacks can look like "normal" traffic (Example, DDoS)
5. Federated Design, difficult to coordinate defense
What is a drawback of packet-switched networks?
A large number of senders can overload a network resource such as a node or a link.
What kind of attacks are packet-switched networks very vulnerable to?
Resource exhaustion attacks
what is a Resource exhaustion attack?
What are the components of security?
1. Availability - ability to use a resource
2. Confidentiality - concealing information
3. Authenticity - assurance of origin of information
4. Integrity - prevent unauthorized changes
What is a Threat?
A potential security violation
What is an attack?
An action that violates a security policy.
What does eavesdropping attack?
What is "Eavesdropping"?
Where an attacker get unauthorized access to messages. The attacker can see the parts or all of the packets!
Packet sniffers can do this.
What is a "man in the middle attack"?
intercepting traffic and modifying it
In eavesdropping, what might the DNS information tell one?
What websites the victim is visiting
In eavesdropping, what might the packet headers tell one?
Type of applications
In eavesdropping, what might the payload tell one?
If "Eve" modifies the packet, what kind of attack is this?
An authenticity attack
What are the impacts of attacks?
1. Theft of confidential information
2. Unauthorized use
3. False information
4. Disruption of service
What protocol does routing security deal with?
What is the goal of control plane authentication?
To determine the veracity of routing advertisements
1. Session authentication (point to point)
2. Path authentication (protects the AS path)
3. Origin auth (protects the origin AS)
What does route hijacking attack?
How do attacks on routing occur?
1. Configuration Error. Whoops!
2. Router could be compromised and reconfigured
3. Unscrupulous ISPs.
What are 3 types of attacks on Routing?
1. Reconfigure router/ tamper with management software
2. Tamper with software
3. Tamper with routing data
What is the most common type of Routing attack?
"Hijacking" or attack on origin authentication
Why do hijacks matter?
Hijacking can lead to DNS Masquerading where an attack uses the BGP to hijack.
What is a man in the middle attack?
Where the traffic ultimately reaches the correct destination, but first goes through the attacker. The attacker has placed themselves on the route!
What is AS Path Poisoning?
When the attacker autonomous system advertises a route that includes the ASes in the path to the REAL AS.
How can an attacker hide from a trace route?
By not decrementing the TTL.
What does session authentication attempt?
Ensure that BGP routing messages sent between routers between ASes are authentic.
Why is session authentication easier than it appears?
Because the sessions are TCP sessions. So just authenticate the session using MD5 authentication.
What does MD5 authentication consist of?
Every message has a message and a hash of the message with a shared secret key. The secret key has to be agreed upon by BOTH ASes, and this is typically done "out-of-band".
What is the "TTL Hack"
A defense mechanism to perform session authentication. A sender sends packets with a TTL of 246. The receiving AS drops packets that have a TTL < 245. This works because most eBGP sessions are a single hop. This ensures session auth because the TTL from an attacker would have to be < 245.
What does "Secure BGP" consist of?
1. Origin/Address Attestation - certificate (signed by a trusted party) binding the prefix to the owner organization.
2. Path Attestation. Signatures along the AS path.
Which kind of attacks can Path attestation protect against?
Which kind of attacks can path attestation NOT protect against?
Where can a MITM attack be used to attack DNS Security?
When the sub resolver queries the caching resolver
Where can cache poisoning be used to attack DNS security?
On a caching resovler
Why is DNS Vulnerable?
1. Resolvers trust responses (even if they are forged)
2. Respones can contain info unrelated to the query
DNS Queries are Connectionless (UDP)
DNS Cache Poisoning...
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