Denial of Service is a family of attacks that attempt to force a target to use up resources (CPU time, memory, bandwidth etc) through flood a target with useless packets, connections or tasks

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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 ...
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How does a DOS attack work when attacking a single server with a single client?

How is it possible to make a DOS attack from a single computer? Let us assume two computers, one acting as server and the other as client. Both has 100/100 mbit bandwitdh. How can then the client ...
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Prevent denial of service attacks against slow hashing functions?

I've been thinking about bcrypt recently, and what I wonder is if there's a way to deal with the inherent (D)DoS problems with slow hashing functions. Namely, if I set up bcrypt so my machine takes ...
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Could somebody explain connect loop DoS?

I'm trying to understand this vulnerability. How can I reproduce this?
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How do I protect my Windows computer against the IPV6 flood attack shown in this video

In the DefCon video "Three Generations of DoS Attacks (with Audience Participation, as Victims)", the speaker demonstrates how it is possible to crash a variety of devices by flooding them with IPV6 ...
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Protecting against DOS attacks

Our current site is easily DOS'd. I can perform an AB test against it from Apache and it disappears for about 5-10 minutes. We have been having problems with others DOSing the site - to the point ...
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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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Are COMET installations immune to “Slow TCP Reading” DoS on Windows? (Such as SignalR or WebSync)

My understanding is that COMET implementations of WebSync and SignalR do not directly use IIS and are a few layers lower on the ISO model. After reading Qualys's blog regarding slow TCP reading, I ...
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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 ...
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Is this type of ARP poisoning attack possible?

I am wondering if it is possible to paralyze a network by sending out a bunch of fake ARP response packets. Some basis: I recently read a moderately detailed description of how ARP and ARP poisoning ...
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How are server overload and DoS/DDos different?

I know that server overloads are caused due to excessive number of genuine requests and DoS due to malicious request. But, my question is, if you have designed a system for Overload mitigation, does ...
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How to defend against SSL-Exhaustion attacks?

The problem of SSL-Exhaustion attacks is well known for years, but nobody really cared until THC released their exploit-tool recently. THC talks about counter measurements in their release: No real ...
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How to patch against RefRef's DOS attack

Overview Anonomous claimed responsibility today for the Denial of Service attack against wikileaks. They are using a new software called RefRef. It seems to exploit MySQL using the server's ...
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Combat Apache Killer

Three days ago, KingCope released a simple Perl script to DoS Apache, aptly named Apache Killer. This script launches about 50 threads to request Partial Content from the server with optional GZIP ...
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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. ...
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What lessons about Denial of Service can we learn from Egypt's “experiment”?

Internet service was widely disrupted in Egypt starting Jan 27th at about 22:15 UTC, in the space of about 20 minutes: How Egypt Killed the Internet. Service was largely restored 5 1/2 days later on ...
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Protection against account lockout DoS

Any ideas on how to protect against the following scenario? Company x uses active directory for authentication of it's employees. The company has multiple authentication points that are semi-public ...
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Why do sites implement locking after 3 failed password attempts?

I know the reasoning behind not letting infinite password attempts -- brute force attempts is not a meatspace weakness, but a problem with computer security -- but where did they get the number 3 ...