286 votes
Accepted

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).
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  • 2,651
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 ...
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  • 6,768
85 votes
Accepted

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 votes
Accepted

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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74 votes
Accepted

Can attackers get anything with DoS attacks except crashing the service?

In general a (Distributed) Denial of Service attack will not provide you with much information directly. However, there are a few scenarios where information could be gleaned as a result of a DoS. The ...
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  • 1,157
60 votes

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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  • 123k
46 votes

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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  • 27.2k
40 votes
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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 ...
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  • 744
39 votes

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 ...
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37 votes
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New denial-of-service vulnerability in TLS protocol, based on shooting down other users' sessions?

To summarize: It may work, or not, depending on how the server manages its cache for session parameters. The RFC are not consistent. It is not a "real" vulnerability. TLS sessions were ...
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37 votes
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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 ...
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  • 6,768
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 ...
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  • 435
23 votes
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Does clicking lead to DoS attack?

The question is a bit vague, the short answer is Yes clicking on links could DoS your site. A for a more in-depth answer you would need to look at what those links are doing. For example if every ...
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  • 4,138
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
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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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22 votes
Accepted

What is the difference between login throttling and temporary account lockout?

A) Yep you got it. Same in that they both result from a failed login attempt(s), though they differ in things like logging, the resulting UX implementation, and when one is used. If a user is ...
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21 votes
Accepted

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 votes

How to prevent smurf attack?

The ICMP packets coming back were in response to your host sending out UDP packets to other hosts who don't have port 2054 open. It was not a smurf of any sort, unless someone remotely compelled your ...
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  • 3,976
20 votes

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 ...
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19 votes
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How does HTTPS help websites under DoS attacks

The only reason switching to HTTPS might help is if the attack is focused on only HTTP. There is no inherent DOS protection in HTTPS. In contrary, you could probably tie up the resources of the server ...
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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 ...
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  • 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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  • 34.4k
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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16 votes
Accepted

802.11w protected management frames - Wi-Fi

I read that this MIC is derived from the PSK (e.g. WPA2 key). Does this mean that these frames are still spoofable from inside the network (i.e. if you own the PSK)? Or does it defend against ...
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  • 1,094
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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  • 41.8k
14 votes

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 ...
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  • 2,988

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