284
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Can someone take down Wi-Fi signal?
There's a lot of ways you can attack a WiFi without knowing any passwords:
Physical layer attacks: Simply jam the frequency spectrum with your own signal. That signal might just be noise, but it ...
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137
votes
Does it make sense to consider a triggerable server software crash a DOS attack?
Yes. Any attack which has as a goal to deny the normal usage of a service by legitimate users is by definition a DoS (Denial of Service).
- 2,691
99
votes
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How can ISPs handle DDoS attacks?
There are a number of strategies, each having their own costs and benefits. Here are a few (there are more, and variations):
blackholing
By blackholing traffic, you discard all traffic towards the ...
- 6,898
85
votes
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Is it safe to let a user type a regex as a search input?
I would compare accepting user supplied regular expressions to parsing most sorts of structured user input, such as date strings or markdown, in terms of risk of code execution. Regular expressions ...
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84
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Can a DDoS attack yield any information?
A DDoS will certainly give an attacker information about response times, load capability and routing.
It may also give information about how incidents are handled internally and externally, as well ...
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60
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Does it make sense to consider a triggerable server software crash a DOS attack?
DDoS (Distributed DoS) is characterised by floods creating a DoS (in all available definitions). A single node causing a flood successfully is kind of rare.
But DoS can be caused by a broad range of ...
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46
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Normal usage vs. denial-of-service? How many requests are needed to talk about a denial of service?
Enough to cause the service to be denied to someone. Might be 1 unexpected malicious request, which causes excessive load on the server. Might be several million expected requests, from a TV advert ...
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41
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Why does a (D)DoS attack slow down the CPU and crash a server?
How does one crash a server using (D)DoS?
To specifically answer your question, to crash a server using only DDoS you need to target the Application Layer (detailed explanation below). These types of ...
- 754
39
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Cloud-based DDoS as a Service
... but they used their own infrastructure
It's not really their own infrastructure what they use. They use instead botnets consisting of hijacked systems. These are systems which they p0wn but ...
- 198k
37
votes
Accepted
Is it illegal to DDoS a phishing page?
If you do a DDoS by sending large amounts of traffic to that site, you're very likely creating a lot of collateral damage since other services in (parts of) the network will suffer as well if the ...
- 6,898
32
votes
Accepted
Is unauthorised deletion an integrity or availability issue?
As pointed out in this (unanswered) question, Availability in CVSSv3 is about how well the web service performs, not whether its data is available:
While the Confidentiality and Integrity impact ...
- 435
23
votes
Is there any way to stop DDOS attacks?
If you're running a website that's under attack, you should consider a service such as Cloudflare.
Cloudflare and other CDNs are designed with DDoS attacks in mind - traffic passes through Cloudflare'...
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23
votes
Accepted
Is deleting files from a database considered a denial of service attack?
Yes, in the sense that anything which "denies service" is a "denial of service".
The CIA Triad defines information security as anything which affects Confidentiality, Integrity, or Availability of ...
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21
votes
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Defending against DoS via product reservation
I've seen 2 main solutions:
Your products are being reserved for X minutes
I've seen notices like this occasionally, but only on places where inventory really matters (usually ticketing sites).
I've ...
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20
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How to deal with this denial of service attack on an Apache server?
This is a classic SYN flood attack, preventive measures include
hashing syn packets, implementing syn cookies
checking if the client properly sends RST after an invalid packet sent back to him
ddos ...
- 2,154
19
votes
Accepted
DoS in local network computer
A little background first. As you know, when communicating over a network, programs split raw data into "packets", which as well as this raw data also contain some extra information:
Where does this ...
- 788
19
votes
Can someone take down Wi-Fi signal?
There are devices that you can buy that will 'jam' a Wi-Fi signal and make it unusable.
Also Wi-Fi has different 'channels' that they can be set to run on. If your Wi-Fi is running on a channel that ...
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18
votes
Why does a (D)DoS attack slow down the CPU and crash a server?
A SYN flood isn't about exhausting CPU, it's about exhausting memory.
A TCP connection is established through what is known as a "three-way handshake". Traditionally, it works as follows:
Client ...
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18
votes
Accepted
Difference between Amplification and Reflection Attack?
TL;DR: amplification attack is a reflection attack where the reply is larger than the the request.
Reflection attack is if the reply is send back to the claimed origin of the request. With a spoofed ...
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15
votes
Is it safe to let a user type a regex as a search input?
The main threat in accepting regular expressions will be in your regex execution engine rather than accepting regex itself. I'd expect the threat to be very, very low in any well implemented engine. ...
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14
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Can a DDoS attack yield any information?
A full answer would be depending on the attack and what would be attacked, so I will keep it general.
A DoS can leak information as a side-effect. In earlier times switches were used in networks to ...
- 3,008
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Threshold for DDOS Attack
Nowadays TCP SYN attacks are not common, focus more on UDP amplification attacks over DNS, memcache and other UDP services. On the other hand, if you want to compute the traffic rate you can use the ...
- 2,257
13
votes
Is there any way to stop DDOS attacks?
There are several types of Distributed Denial of Service attacks, mitigation techniques can be specific to each case:
Volumetric Attacks
A few computers send a large amount of traffic, clogging the ...
- 3,580
13
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Is it illegal to DDoS a phishing page?
Report the phishing site so browsers can warn the users and show red pages. It's much more efficient and it's completely legal: https://www.google.com/safebrowsing/report_phish/
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Why are DDos-Attacks still possible?
Blocking attack traffic at the firewall will mitigate an attack designed to overwhelm server CPU or memory resources, but most high-profile attacks simply send a flood of data aiming to exhaust the ...
- 10.4k
12
votes
Accepted
How to perform a proper DDoS test in a safe and controlled way?
If you are performing load testing at high packet rates, the most safe way is to isolate it completely from the rest of the network. For example, you can connect two servers by direct 10GBps link ...
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12
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Is unauthorised deletion an integrity or availability issue?
I would say it presents a clear Availability issue as the attacker is able to completely remove that specific resource and prevent other users' ability to access.
I would also say there is an ...
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10
votes
Can a DDoS attack yield any information?
Identify shared resources
A Denial of Service attack, distributed or not, can be used to successfully identify machines which share resources. If you want to hack a service, you can launch an attack ...
- 204
10
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Why does a (D)DoS attack slow down the CPU and crash a server?
A DDoS usually doesn't crash a server. It overloads it, making it unavaible for normal use. The "best" way to achieve this depends on the function of the server and the way it's configured. There are ...
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