Skip to main content

Questions tagged [ddos]

Distributed Denial Of Service (DDOS) is the intentional paralyzing of a computer network by flooding it with data sent simultaneously from many individual computers (so-called zombies) which are used to stage DDOS attacks

Filter by
Sorted by
Tagged with
139 votes
8 answers
32k views

I got an email threatening to DDOS me if I don't pay a ransom. What should I do?

I received the following email, addressed to me at an email address on my personal domain (for which I run my own mail server on a VPS): FORWARD THIS MAIL TO WHOEVER IS IMPORTANT IN YOUR COMPANY ...
alexw's user avatar
  • 1,289
124 votes
4 answers
111k views

What is the website checking about my browser to protect the website from a DDoS?

Some sites I visit take me to a page that says roughly, "Checking your browser before accessing example.com. DDoS attack protection by CloudFlare". What exactly about my browser is being checked and ...
user avatar
109 votes
12 answers
43k views

Why is it difficult to catch "Anonymous" or "Lulzsec" (groups)?

I'm not security literate, and if I was, I probably wouldn't be asking this question. As a regular tech news follower, I'm really surprised by the outrage of Anonymous (hacker group), but as a ...
claws's user avatar
  • 2,175
100 votes
11 answers
31k views

DDoS: Why not block originating IP addresses?

I'm a moderator of a major bulletin board. When a baddie shows up, we block their IP address; it works, at least until they find a new one. Why can't a protocol be developed for the world's routers to ...
vonlost's user avatar
  • 1,155
80 votes
5 answers
90k views

How do major sites prevent DDoS? [duplicate]

As far as I know, I have never heard of or seen any large scale web sites like Amazon, Microsoft, Apple, Google, or Ebay ever suffer from DDoS. Have you? I have a personal philosophy that the bigger ...
Lakitu's user avatar
  • 931
80 votes
5 answers
37k views

What techniques do advanced firewalls use to protect againt DoS/DDoS?

It is hard to protect a server against Denial of Service attacks, DoS/DDoS. The two simple ways I can think of is to use a server with much resources (e.g. CPU and memory), and to build the server ...
Jonas's user avatar
  • 5,203
73 votes
4 answers
12k views

Did I participate in the recent DDoS attacks on Dyn's DNS service?

It was reported that the recent large scale DDoS attack affecting multiple websites in the US was done by hacking 10s of millions of devices and using them for the attack. How can one in general know ...
Thomas's user avatar
  • 3,861
70 votes
2 answers
22k views

How can ISPs handle DDoS attacks?

How can an ISP with low bandwidth like 50 Gbps handle a DDoS attack with more than this? I know there is a solution called "Black Hole". Is this enough to mitigate DDoS attacks or are there any other ...
R1W's user avatar
  • 1,627
57 votes
11 answers
17k views

Can a DDoS attack yield any information?

Can a DDoS attack reveal any information or be used to mount a hack? My understanding is that the whole point of DDoS or DoS is to consume all of the resources/overload the server causing it to crash. ...
KosugiNinja's user avatar
53 votes
6 answers
8k views

Why don't browser DNS caches mitigate DDOS attacks on DNS providers?

Why are the recent DDoS attack against DNS provider Dyn, and other similar attacks successful? Sure a DDoS attack can bring an entity down, and if that entity controls DNS servers then queries to ...
aeb0's user avatar
  • 650
48 votes
13 answers
43k views

DDoS - Impossible to stop?

Is it possible - in theory - to stop1 a DDoS attack of any size? Many people claim it's impossible to stop DDoS attacks and tell me I just shouldn't mess with the wrong people on the internet. But ...
user2173629's user avatar
36 votes
2 answers
8k views

How can a Software application defend against DoS or DDoS?

Most of the solutions for DoS attacks are not at the application level. In case I am using a proxy server, what are the possible countermeasures for DoS at the application level?
Phoenician-Eagle's user avatar
35 votes
2 answers
5k views

Digging into DDoS attacks (includes hostile IP's from multiple honeypots)

I have been tracing a series of DDoS attempts, and am wondering if anyone else has seen anything like them. I've downloaded the following Powershell script which scrapes Terminal Server (RDP) Event ...
turkinator's user avatar
34 votes
4 answers
13k views

Is serverless code immune to DDoS attacks?

In classic hosting we have a virtual machine with limited resources allocated by hosting provider for running our web application. But with serverless code such as AWS Lambda or Azure Functions, our ...
Mr. Engineer's user avatar
32 votes
3 answers
12k views

How do DoS/DDoS work?

In the last days one could frequently read about attacks from anonymous and LulzSec against different platforms like Sony or HBGary etc. Yesterday for example they DDoS'ed soca.gov.uk and jhw.gov.cn. ...
binfalse's user avatar
  • 493
27 votes
6 answers
17k views

Someone knows my IP and is threatening to DDoS me

Around 4 months ago, someone learned my IP, and is threatening to DDoS attack me if I am not his slave. He was breaking the Discord TOS with all kinds of stuff in my DMs. I blocked him, but one of his ...
user avatar
27 votes
5 answers
4k views

DDOS - security or operational risk?

The chief security officer of a medium sized IT company (400-500 employees) recently released a bulletin in which he stated that DDOS attacks are not a security risk but an operational one. Also I was ...
fgysin's user avatar
  • 754
27 votes
2 answers
9k views

How is Google abused for DDoS attacks?

While analysing a DDoS attack on my site using CloudFlare console, I've noticed that many attack requests come from AS139190 GOOGLE-AS-AP Google Asia Pacific Pte. Ltd. with Empty user agent. I'm ...
blnks's user avatar
  • 383
24 votes
6 answers
5k views

Why do DDoS attacks cost a fortune to stop?

I have read so many stories that a major DDoS attack is causing companies thousands of dollars to mitigate. I have two questions: Is this because they try to keep the servers accessible to real site ...
IMB's user avatar
  • 2,968
24 votes
2 answers
12k views

Reject IP packets with an ICMP error, or just drop them?

Consider an internet-facing host (the outer firewall). What should be done with undesired traffic: just drop it, or send back an ICMP error such as port unreachable? (In Linux terms: iptables -P DROP ...
Gilles 'SO- stop being evil''s user avatar
23 votes
4 answers
14k views

Why does a (D)DoS attack slow down the CPU and crash a server?

So I get the basic idea of (D)DoS used for flooding, but I don't quite understand how this causes servers to crash or get them to slow down due to CPU overuse. As far as I know, the thing that is ...
DrDoom's user avatar
  • 455
23 votes
10 answers
88k views

How do I know if my computer is being used for a botnet-based DDoS attack?

A botnet is a collection of compromised computers, each of which is known as a 'bot', connected to the Internet. When a computer is compromised by an attacker, there is often code within the ...
Diogo's user avatar
  • 657
22 votes
2 answers
5k views

Does the amount of bandwidth available on a network determine how strong a DoS attack should be?

Does bandwidth alone determine how many packets a router or server can handle before the server is overran and then goes offline?
99Con's user avatar
  • 427
22 votes
3 answers
8k views

Since I can set the source IP address to anything using raw sockets, does this mean I am untraceable?

For homework, I coded a TCP packet with raw sockets. So I was also able to change the source IP address to whatever I wanted. So why can't someone just make a program, which sends millions of these ...
Joey's user avatar
  • 605
22 votes
5 answers
27k views

How to simulate DDoS attacks from the Internet?

The idea behind security tests is easy. You want to know what a hacker can do - you hire a security expert who acts like a hacker to see how far he can get. You want to know what an evil admin can do -...
Demento's user avatar
  • 7,465
21 votes
7 answers
7k views

Prevent a bot accessing login page with multiple IPs and massive list of username/ passwords

For the second time my website seems to be the target of a large automated attack. It seems complex enough and very well executed. I have the following systems in place: Captcha on 3rd failed login ...
contool's user avatar
  • 323
20 votes
2 answers
2k views

Web Developer's responsibility for DDoS [closed]

If my website is targeted for a DDoS attack after I have been paid for completing the website, and I get an angry phone call from the client regarding outage of service, what do I do? It hasn't ...
Dmytro's user avatar
  • 351
19 votes
4 answers
913 views

Global Blackout is a myth?

In order to shut the Internet down, anonymous claimed that putting-down the 13 root DNS servers of the Internet and therefore disabling the HTTP Internet, the most widely used function of the Web, ...
Tawfik Khalifeh's user avatar
18 votes
5 answers
6k views

Cloud-based DDoS as a Service

With the consolidation of cloud computing and virtualization, a really simple doubt comes to my mind: why isn't DDoS being largely offered as a service? Why don't we see cloud-based DDoS attacks? ...
Gabriel Rebello's user avatar
18 votes
3 answers
2k views

NTP DDoS Attack on Home Servers

After some half-good script kiddies found out about this exploit or DDoS method, they have been doing it like crazy to websites, game servers, and now my home servers which allows me to work on some ...
user avatar
18 votes
3 answers
11k views

DNS Amplification DDOS attack

During the weekend I made some tests to simulate an DNS Amplification DDOS attack. sending about 90Mb/s traffic I was able to generate about x.x Gb/s amplified traffic which sent our datacenter ...
HEX's user avatar
  • 531
18 votes
4 answers
9k views

Accessing a site (which is) under a DDoS

Lets say http://www.an-example-site.com is under DDoS attack. Alice, who does not have direct access to the hardware infrastructure, urgently wants some information which can be accessed through the ...
check123's user avatar
  • 544
18 votes
1 answer
2k views

Why is the Wikileaks site still accessible? How come it hasn't been hacked? [closed]

Let me get started by saying I think Wikileaks is great, and that their work is invaluable. Background/context for this question: The recent Wikileaks data dump on the CIA. I've visited the site ...
Mr. Chameleon's user avatar
17 votes
7 answers
2k views

Would it be possible to overload a large part of the internet, and if so then how?

Last week a news article went viral about a Dutch web hosting/data center company that was allegedly using a DNS amplification attack to DDoS an anti-spam company, because they blacklisting the former....
Chris's user avatar
  • 273
16 votes
8 answers
17k views

How does CAPTCHA mitigate DDoS attacks?

This seems like an easy question, but I've failed to find an answer. One of the uses of CAPTCHA is to cope mitigate Denial of Service attacks. Suppose an adversary performs excessive login attempts, ...
overrider's user avatar
  • 263
16 votes
6 answers
10k views

What is a DoS Attack and how does it differ from a DDoS attack?

Can someone explain to me the concept of DoS attacks for web applications? Also, what is the distinction between DoS and Distributed DoS (i.e. DDoS) attacks? Wikipedia says: In computing, a denial-...
Geek's user avatar
  • 263
16 votes
1 answer
2k views

How to make a report after a ddos attack? what information do I need to write on the report?

In my company, after a DDOS against a server, my employer asked me to make an analysis of the attack and to write down some stuff. What do you think I need to write down in my report? Is there any ...
boos's user avatar
  • 1,066
15 votes
4 answers
5k views

How to deal with this denial of service attack on an Apache server?

I was the target of different attacks today. The last one created this traffic on port 80. Apache is down and the load on server remains high. Firewall is enabled. Any suggestions? 15:27:10.203993 ...
antony's user avatar
  • 309
15 votes
3 answers
2k views

External websites in logs [duplicate]

I have a website, let's call it www.good.com. I've been getting a lot of requests to www.good.com under completely different URLs than www.good.com. I suspect this traffic is also causing some site ...
Zachary Dow's user avatar
13 votes
3 answers
3k views

What prevents me from launching an SYN-ACK flood using HTTP servers?

I've been studying networks lately and this issue came across my mind. What prevents me from sending a lot of SYN requests with source address of my (attack's) target and flooding the target's ...
tensojka's user avatar
  • 239
13 votes
4 answers
11k views

Looking for botnet IP address feeds to protect against DDoS

I would like to get a live feed of botnet IP addresses delivered from a service and block them under certain conditions. Preferably community based/open source but open to looking at worthy commercial ...
shavian's user avatar
  • 139
13 votes
4 answers
15k views

How to perform a proper DDoS test in a safe and controlled way?

What is the proper and safe way to perform a DDoS test without crashing the whole infrastructure? What different types of DDoS attacks are there and what things should be considered performing such a ...
Bob Ortiz's user avatar
  • 6,675
13 votes
1 answer
661 views

Siri DDoS over FM Radio

A few days ago I was driving home and suddenly Siri started to talk by herself in reply to a command I never gave. As you can imagine I have the "hey siri..." feature active, so I can make calls ...
AcidRod75's user avatar
  • 243
13 votes
1 answer
1k views

What happens inside of a DDoS Scrubbing Center?

I understand, that traffic is redirected to a scrubbing center during a DDoS to differentiate between malicious and legitimate traffic as has been explained in this post. However, from a technical ...
Ma.Na's user avatar
  • 131
12 votes
4 answers
4k views

Webserver DDOS protection without giving away private keys (https, tls, ssl)

What are the possible ways to protect an organization's web servers from a DDoS attack without giving away your web server's https private keys? Many of the common solutions for DDoS protection of a ...
Michael Altfield's user avatar
12 votes
1 answer
25k views

dns reflection attack vs dns amplification attack

Over the past few weeks I have heard discussions about a DNS reflection attack and a DNS amplification attack. Is there truly a difference between the two or are people just using 2 different names ...
user3271518's user avatar
12 votes
4 answers
8k views

mitigating anonymous DOS (tor combined with pyloris)

I found this rather scary video in youtube, that takes DOS to a whole new level, by making it look like coming from multiple sources. As a counter measure to Rsnake (Robert Hansen) slowloris.py script,...
Tawfik Khalifeh's user avatar
12 votes
2 answers
2k views

How to test against DDoS in a controlled enviroment?

Can you suggest me methods or tools that can help in simulating a DDoS attack in a controlled enviroment (like my private lab)?
gbr's user avatar
  • 2,020
11 votes
3 answers
20k views

How to protect myself against paid DDoS services?

I am domestic user and I am getting attacked regularly by a guy that hates me. Here is the background story: that guy uses Skype resolvers (tools offered by paid DDoS services) to find out my IP ...
IneedHelp's user avatar
  • 213
11 votes
4 answers
7k views

Can I protect my router from a Mirai Worm and how do I know if I'm vulnerable?

Today this article was published by the BBC: Talk Talk and Post Office routers hit by cyber-attack. It states: It involves the use of a modified form of the Mirai worm - a type of malware that is ...
User1's user avatar
  • 3,041

1
2 3 4 5
11