What is a DDoS Attack?
A Distributed Denial of Service (DDoS) Attack is an attack that attempts to make your website or application unavailable to your end users.
This can be achieved through multiple mechanisms, such as large packet floods, but using a combination of reflection and amplification techniques, or by using large botnets.
What is a Layer 4 DDoS Attack?
A Layer 4 DDoS Attack is often referred to as a “SYN flood”. It works at the transport layer (TCP).
To establish a TCP connection a 3-way handshake takes place. The client sends a SYN packet to a server, the server replies with a SYN-ACK, and the client then responds to that with an ACK.
After the “3-way handshake” is complete, the TCP connection is established. After this, applications begin sending data using Layer 7 (application layer protocol), such as HTTP, etc.
A SYN Flood uses the built-in patience of the TCP stack to overwhelm a server by sending a large number of SYN packets and then ignoring the SYN-ACKs returned by the server. This causes the server to use up resources waiting for a set amount of time for the anticipated ACK that should come from a legitimate client.
What happens to the server when it is under a SYN Attack?
There are only so many concurrent TCP connections that a web server or application server can have open, so if an attacker sends enough SYN packets to a server, it can easily eat through the allowed number of TCP connections.
This then prevents legitimate requests from being answered by the server.
What is an Amplification Attack?
Amplification/reflection attacks can include things such as NTP, SSDP, DNS, CharGEN, SNMP attacks, etc.
This is where an attacker may send a third-party server (such as an NTP, or Network Time Protocols, server) a request using a spoofed IP address.
That server then responds to that request with a greater payload than the initial request (usually within the region of 28-54 times larger than the request) to the spoofed IP address.
This means the attacker sends a packet with a spoofed IP address of 64 bytes, the NTP server would respond with up to 3,456 bytes of traffic.
Attackers can coordinate this and use multiple NTP servers as second to send legitimate NTP traffic to the target.
What is a Layer 7 Attack?
A Layer 7 attack occurs where a web server receives a flood of GET or POST requests, usually from a botnet or a large number of compromised computers.
What is AWS CloudTrail?
AWS CloudTrail increases visibility into your user and resource activity by recording AWS Management Console actions and API calls and storing the logs in S3.
You can identify which users and accounts called AWS, the source IP address from which the calls were made, and when the calls occurred.
This of CloudTrail as CCTV monitoring for your AWS account.
What is an example of activity that is not recorded in AWS CloudTrail?
RDP or SSH traffic
What information is logged in AWS CloudTrail?
What are the benefits of AWS CloudTrail?
What is AWS Shield?
It is free DDoS protection
What is AWS Shield Advanced?
It provides enhanced protections for your applications running on Elastic Load Balancing (ELB), Amazon CloudFront and Route 53 against larger and more sophisticated DDoS attacks.
What are the costs related to AWS Shield Advanced?
Shield Advanced costs $3,000 USD per month
What layers does AWS Shield protect against?
Layer 3 and Layer 4 attacks
What is AWS WAF?
AWS WAF is a web application firewall that lets you monitor the HTTP and HTTPS requests that are forwarded to Amazon CloudFront or an Application Load Balancer.
AWS WAF also lets you control access to your content.
You can configure conditions such as what IP addresses are allowed to make this request or what query string parameters need to be passed for the request to be allowed.
The Application Load Balancer or CloudFront will either allow this content to be received or give an HTTP 403 status code.
What layer does AWS WAF operate at?
Layer 7
If you are given a scenario that talks about Layer 4 attacks, what service would you recommend?
AWS Shield
If you are given a scenario that talks about Layer 7 attacks, what service would you recommend?
AWS WAF
What are the behaviors of AWS WAF?
What characteristics of web requests can you use to define conditions in AWS WAF?
What type of attacks can AWS WAF protect against?
What is Amazon GuardDuty?
GuardDuty is a threat detection service that uses machine learning to continuously monitor for malicious behavior, like:
What are the features of Amazon GuardDuty?
How does the threat detection using AI work in Amazon GuardDuty?
It takes 7-14 days to set a baseline - what is normal behavior in your account?
Once active, you will see findings in GuardDuty console and in CloudWatch Events only if GuardDuty detects behavior is considered a threat.
What are the fees related to using AWS GuardDuty?
The first 30 days are free!
And then your charges are based on: