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

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Stopping DDOS TCP SYN and UDP flood attacks

I would like to know if it's possible to stop a TCP SYN OR ICMP Flood attacks if these attacks are detected at time. What is the most accurate process to filter these addresses if the only way is to ...
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1answer
124 views

Botnet Attempting to Login to Website

Our server has recently become a target of what appears to be a botnet attack. The first indication was an insane amount of traffic to one of our client's websites - so heavy that the server entirely ...
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7answers
7k 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 ...
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5answers
1k views

I have a client that is worried about DDOS attacks on their site, and they want penetration testing. Will that help?

My client wants to look into hiring a third party to perform penetration tests on the website that we're developing for them. The website is just a simple 3-month contest site where people can upload ...
17
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3answers
4k 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 ...
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7answers
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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 ...
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3answers
1k views

How will IPv6 affect DDoS mitigation techniques?

IPv6 introduces a much larger address space than IPv4 and with it there are many new techniques in creating and mitigating DDoS attacks. What are some examples of risks and mitigations? For example, ...
0
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1answer
446 views

DDoS prevention (LOIC doesn't do the job anymore) [closed]

We are about to launch a important webservice. We must test it for DDoS. From other questions/answers here I learned about LOIC. Downloaded, tried, but my apache refuses it. What other ready made ...
2
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0answers
184 views

Snort Parallelization Techniques and its effect on DDOS detection capability

I want to ask a query about snort parallelization. 1) Can snort detection rate remains same for all attacks after parallelisation? 2) As the parallelisation of netowrk traffic in each core is based ...
2
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3answers
913 views

Why is it easy to detect network layer DDoS attacks?

I have seen numerous research papers that claim it is "easy to detect network layer DDoS attacks" without saying why. Usually these research papers focus on detection or prevention of application ...
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3answers
143 views

DDOS protection for instant messenger server

I developed an instant messenger which uses TCP ports for its communication, and hosted the server application on a VPS account from some hosting company, but the first day I got attacked by a ...
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2answers
648 views

How to mitigate SIP Reflection Attacks?

SIP has a practical need to be widely available, but its services are prone to being spoofed as reflectors used in DDoS attacks. A freeswitch server I manage has seen heaps of registration requests ...
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2answers
2k views

How to Secure a Stream from DDoSers?

I conduct a weekly live-stream using Google Hangouts that streams over YouTube. Recently, the stream has been attacked by DDoSers. In an attempt to thwart such attacks, I have tried to keep my IP ...
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6answers
891 views

how to mitigate a DDoS from botnet on your website that comes from random IPs

I am wondering how do you mitigate a ddos attack which is coming from a botnet and hitting random URLs on a website. If there was a consistent URL it was hitting then it would be fairly simple, and ...
4
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3answers
113 views

Where is the limit between an attacker and a victim (zombie) in a DDoS attack

Let's say that A is DDoSing B and I'm a member of his botnet. Who says that I'm not a real attacker but a victim? How you determine it?
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3answers
707 views

unknown MAC address in the LAN, DD-WRT router

I am using a linksys router with DD-WRT firmware with a WiBro internet connection, the ISP uses a hub with multiple user connected to it. The issue is that an unidentified MAC address seems to pop up ...
4
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6answers
456 views

Bot detecting by considering request inter-arrival time

If there are some chances to detect a bot by considering the users page viewing time, is it possible to measure this time? When a user request for a page (page request), browser request for several ...
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3answers
279 views

How similar are bots regarding their HTTP GET request?

Lets assume a botnet is attacking a website by HTTP GET flooding. To find the bots, the only way seems to be finding the similarities of the HTTP GET requests considering the URL and header fields, ...
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1answer
514 views

Creating a DDoS attack using DirectConnect

I have been trying to hack around with Apex DirectConnect. What I wish to do is to utilize the querying nature of P2P apps like DC to generate a DDoS attack (see links for reference here, here and ...
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3answers
13k views

How can I identify open DNS resolvers in my network?

This article highlights how open DNS resolvers are being used to create DDOS attacks across the internet. How can I identify whether any of our DNS servers are open? If I find that we are running ...
2
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3answers
865 views

DDoS on LAN: How to Defend?

DDos on a wired network has to be extremely rare, since the intruder has to be physically connected to the network. However, let's say that it still managed to happen. How would you be able to defend ...
6
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1answer
178 views

Parabolic Denial Of Service — Would it work?

Would this DoS attack be effective: Attacker determines target (10.0.0.1) Attacker sends ack packets to a buch of web servers with a src addr of 10.0.0.1 Servers reply to 10.0.0.1 with syn packets ...
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5answers
1k 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, ...
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5answers
2k views

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

Can some one explain to me the concept of Dos Attacks for web applications ? Also what is the distinction between Dos and Distributed Dos ( ie DDos) attacks ? Wikipedia says : In computing, a ...
2
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2answers
245 views

Can an attacker slow down my server without compromising it?

We have a Linux server with WHM/cPanel which has been running without problems for almost 3 years now. Yesterday, the server became unresponsive (it was definitely there though) for around an hour. ...
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3answers
2k 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 ...
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4answers
652 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, ...
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4answers
3k 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 ...
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1answer
727 views

My server is being DDoS'ed with 13 gbit and my provider nulled my ip, taking down my server - what can i do [duplicate]

Possible Duplicate: How can a Software application defend against DoS or DDoS? Accessing a site (which is) under a DDoS Null-routed IP 85.17.154.139 8/5/12 In progress 13Gb ddos ...
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3answers
214 views

Denial of Service on SSL services

When the SSL handshake takes place, is there a point where the computational work done by the client is significantly less than the computational work done by the server? Could such an imbalance be ...
0
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1answer
886 views

Monitor incoming TCP/UDP flood attack and graph it

I'm preparing a presentation on a security issue and want to include a demonstration. It won't be in real time, I just need to show some pictures of the results. I have some VPSes that will perform a ...
2
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2answers
3k views

IPTables DDoS protection working with per client IP address counter AND UDP

I am looking to protect LAMP server with a software, which will detect above average number of requests from single IP numbers (in this case DNS queries), and add these hosts to IPTables deny chain. ...
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2answers
2k views

DDoS Protection for DNS providers

Zerigo, our DNS provider has reported to have been under heavy DDOS attack in the last 24 hours or so. Considering the distributed nature of DNS, and their architecture consisting of 5 main DNS ...
2
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1answer
119 views

Types of attacks outside of AppSec and Vendor-Specific Systems?

I'm reading up on the OWASP Top 10 for helping me defend my web app against common "app sec"-type attacks (SQL Injection, CSRF, etc.). And in a recent question I was prompted to not only use OWASP Top ...
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4answers
1k views

Spider Attack from several search engines at once

Hello my server is getting hit by spiders from bingbot, google, yahoo, yandex, and some place in the UK all at the same time crashing it. While I have no reason to think any one person did this, it ...
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2answers
93 views

Looking for information about CVE-2006-6876 vulnerability

In order to study vulnerabilities of a SIP server and the impacts of DOS attacks on the QoS of VoIP service, I have found this vulnerability which can be exploited to cause DoS on SIP server. But I ...
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1answer
610 views

Linux tools to choose suitable Cisco ASA 5500

I have a linux webhosting server which affects a high DDOS. I want to use Cisco ASA 5500 Series Adaptive Security Appliances to protect the linux server from this DDOS. I know there are many factors ...
4
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5answers
1k views

SYN Flooding issue

I recently purchased a server with "DDoS protection" and a 1gbps uplink. What I can't figure out, is that I'm suffering from SYN floods. Isn't the large amount of bandwidth available to me supposed ...
7
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5answers
8k views

How to trace a DDOS attack on a dedicated server and block it?

I have a dedicated server and I'm hosting a game, and the web page (using Apache) for account registering. The server is being ddosed since 8 months ago till today. I've tried to talk with the server ...
2
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2answers
960 views

Protection against DDoS when using proxies

We're trying to protect some sites that are primarily located in Asia using distributed caching. These sites commonly come under DDOS attacks. We are using fail2ban, but still have two problems: ...
19
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6answers
3k 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 ...
1
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2answers
5k views

How to conduct DDoS attack practically? [duplicate]

Possible Duplicate: How to simulate DDoS attacks from the Internet? I want to conduct a DDoS attack. Can anyone please tell how can i conduct it? What are the latest DDos attacks? What are ...
6
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4answers
2k views

Block all BotNets and TOR addresses from accessing our site

I've heard that many DOS attacks and general "black hat hacking" attempts occur over the TOR network. Is it possible for me to dynamically block source IP's by their presence in a BotNet or similar ...
4
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4answers
3k views

Using SYN cookies to perform a DOS attack

In my software security class, we had this question: You are the system administrator for a provider that owns a large network (e.g., at least 64,000 IP addresses). Show how you can use SYN ...
5
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2answers
5k views

How can I detect/withstand DNS amplification attack?

I am a developer, and I am trying to get an insight into what could I do to enable my application to withstand a DNS amplification kind of attacks. Would such prevention methods help against DOS type ...
10
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6answers
19k 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 ...
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2answers
6k views

Understanding Layer 7 DoS

I recently read this article about how a lone hacker (The Jester) conducts, amongst various other things, his DoS attacks over layer 7 instead of layer 4. It also mentions at one point he was able to ...
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1answer
1k views

Effects of DDoS attacks on memory use under Linux

Can someone whose Linux system is under DDoS attacks give me exact data on the effects of the Low Orbit Ion Cannon (LOIC), the High Orbit Ion Cannon (HOIC), Slowloris, PyLoris, Hping etc. on memory ...
5
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3answers
470 views

Is this a symptom of an attack (DoS/DDoS)?

I work for an e-commerce website in my country and this is the second time we suffer an attack. At least, looks like one. We have a search functionality in our website and the supposed attacker is ...
2
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1answer
1k views

How should I configure a Citrix Netscaler to protect against HTTP, TCP, or UDP flood attacks?

I have a Citrix Netscaler and want to configure the appliance appropriately so that it can protect my hosts from a DDOS. Is this something I can do here, or must I take action on the host itself?