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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Finding the method of attack [closed]

My server has been repeatedly attacked in the last few days. Here's the observations: The ISP server traffic monitor shows the incoming traffic goes up to 300Mbps (with no outgoing traffic), and ...
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Slowloris attack?

Could someone analyze this info? We got information that slowloris attack took place. They say (hosting stuff) they have implemented mod_antiloris, is that enough btw? Feel free to share your opinion ...
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SSL vs TLS, which is less vulnerable to DOS attacks?

When I learned TLS does not allow a connection to be created until it is has finished a secure handshake, i figured that would make it better for preventing DoS attacks. However, all I seem to find ...
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Is there a security reason for a site to limit the number of times a user can change their password?

Is there a security reason to disallow a user to change their password as frequently as they want? I have found this security policy in a site and I am not sure why it is enforcing it. One reason I ...
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Preventing DoS in Ajax Calls

We have Ajax call to validate the UserID on create page so that user there only can know if their chosen ID is available or not. We have this URL exposed : https://mydomain.com/validateId?id=<user ...
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How can I constrain or limit 3rd party Javascript (*.js) files that can DOS my site?

Many website owners integrate Google analytics, various Facebook or Twitter social media javascript plug ins into their web pages. The problem is that this trust seems to be "all or nothing", meaning ...
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Why should an IKE responder change the cookie secret 'frequently'?

IKEv2 has the concept of a COOKIE mode, to attempt to prevent state exhaustion from floods of initiation requests from non-existent IP addresses: Two expected attacks against IKE are state and CPU ...
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how does a reflection attack work?

I am trying to understand reflection attacks but unfortunately wikipedia is too vague. I understand that in such an attack the attacker tries to authenticate with the target but does so in such a way ...
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What approaches are to detect DoS attack in IDS/Firewall?

First approach to DoS attack detection: There are techniques for intrusion detection, and of course DoS attack, in which for each packet (or flow) some features are calculated, then based on some ...
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Snort/IDS detect and alert on possible DoS/DDoS attack?

As per the title, I'm attempting to configure Snort to detect and alert on a incoming Denial of Service attack. Looking at the rulesets, which are primarily signature based rules, I can't see a ...
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Lessen impact of DoS attack on cpu-expensive login?

This is a follow-up to my previous question: Prevent DOS against RSA authentication. This question is also discusses a similar problem: Prevent denial of service attacks against slow hashing ...
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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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Prevent DOS against RSA authentication

In my current setup, the clients are bundled with the server's public key. The client encrypts a nonce and sends it to the server which uses its own nonce and the nonce received from the client to set ...
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Measuring SNR to detect jammers in Wi-Fi networks

I'm trying to figure out a way to detect a Wi-Fi 2.4 GHz signal Jammer. I am not looking into locating the location of the jammer but rather detect the jamming signal. How do i do so using only ...
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Are latency based Proof-of-Work systems capable of preventing DDoS attacks on popular hidden tor services (.onion websites)?

I was reading an interesting article found here: http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-703.pdf It's titled "Lazy Susan: dumb waiting as proof of work". It suggested the following in section ...
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Is anything written in the book “Internet Denial of Service: Attack and Defense Mechanisms” c2004 still valid? [closed]

I was reading through some of this book on google: http://books.google.ca/books?id=qmdCs_Jf2AEC It is uploaded to a hungarian website here: http://denialofservice.uw.hu/index.html I was reading... ...
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DoSing my Home Network with only a Public IP address [closed]

+--------------------------------------------------------+ | Client Host Name |.. IP Address ..|.... MAC Address ...| | Desktop-Home ....| 192.168.1.100 | 00:19:D1:EA:03:68 | | GT-S5380K ...
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Experience with a recent DDoS attack on Apache

I originally posted a question here since I was not familiar with an actual distributed denial of service attack (DDoS) on my server. I noticed that my server is very slow in responding to HTTP ...
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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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Does “loose source and record route” drop the source address?

Is the source IPv4 address lost when a person uses "loose source and record route" and the destination address is put before the end of the list of addresses through which routing should occur? It ...
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how does a sip flood attack work?

I understand that SIP is an application-level protocol that is used to setup/modify/end communication sessions for things like VOIP and instant messenger. I also understand that users can send request ...
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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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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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Apache/Linux server, DoS attack from own IP

I have an unusual problem I've been trying to diagnose for a while: It's about a Debian server running a custom compile of apache 2.2 with PHP, Red5, MySQL 5.5 (standard binary), sendmail (distro ...
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Secure against HTTP FLOOD ATTACK

What is the best way to defend your web site against HTTP FLOOD POST/GET ATTACK ?
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Denial Of Service attack in asynchronous communication

Is Low rate DOS attack (unintended) possible through asynchronous communication? Consider this scenario: I have a client server application were there is a WAN communication between the client and ...
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Disadvantages of HTTP GET/POST Flooding Attack?

I asked about What is HTTP GET/POST Flooding Attack? recently and I got a few detailed answers about what they are and how they work. Now I want to find out what are the disadvantages of them.
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Is a multitenant web app built on Apache Cassandra more resilient against DoS attacks?

Imagine a multitenant web app that stores data in a Apache Cassandra cluster, with fairly many nodes. Now assume that: Mallory launches a DoS attack against one tenant. (Perhaps that tenant is a ...
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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 ...
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Reflection Attacks on Server

I was reading a research paper entitled "Steps to Defend Against DoS Attacks" when I came across this point: "A reflection attack on a server would require server-client-server communication, ...
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Securing anonymous accessible URL with a GUID segment?

In my problem there is an existing system that works as a alerting or clipping service that runs user defined searches and generates results lists. These are setup by authenticated users and this ...
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Bruteforce vs Denial of Service

I had a problem presented today which I found quite interesting. You have an application with a management panel. You know some of the accounts as they are standard. You want two things: You want ...
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How to know what's the type of an attack and from whom is sent?

I'm currently running a game server on a dedicated Windows 7 machine and it is being attacked. How do I know what kind of attack it is and from whom is sent? When he attacks, the RDP freezes and the ...
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Resource consumption attacks against algorithms

I am studying algorithm construction and weaknesses to resource consumption. One vulnerability that really caught my eye was the Apache Range Header DoS Vulnerability. The following quote was taken ...
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DoS anomaly-based detection: simplest approach beside simple threshold

As I learned, there is this technique in which the number of bytes/packets/frames of aggregated traffic is being checked to see if they deviate from a normal behavior. Then the time slot of that ...
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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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Good steps to survive from denial-of-service attack (DoS attack)

I need to follow several steps to safe our Web Project from DoS attack. Is there any guideline / steps? EDIT : We have our own server where we are running several e-Commerce websites. Our server's ...
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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 ...
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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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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 ...
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Should you care about DoS attacks if your server is using bcrypt?

(I just asked this question on "cryptography SE" and was suggested to ask it here instead) EDIT I just realized my question is mostly a dupe of: Prevent denial of service attacks against slow hashing ...
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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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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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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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SSL Based Denial of Services due to Message Digest

On a very high level, its known that SSL/TLS uses message digests to verify the integrity of the messages sent. However, the question I have in mind is : How does SSL ensure a DoS does not happen ...
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How can one defend against DoS attacks at the physical layer?

Of course, there's always the odd issue of old microwaves and wireless telephone handsets interfering with Wi-Fi performance. And, in many areas, there's a fair chance that you're going to have to ...
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Is it possible to “close” a port by dos'ing it?

If I see port 25 is open, but I dont have access to the program running the smtp server, could It be flooded with enough information to make it unusable (but not affect any other services)?
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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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Differentiate normal flow and broadcast attacks

How do you identify whether a broadcast traffic is normal or is considered an attack such as a DoS attack?, There is some information that the plot or the source that allows me to differentiate ...
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Mass account lockout prevention using CSRF tokens

I'm currently working on reducing the risk of mass account lockout on a site that (unfortunately) issues sequential, numeric user IDs. Changing the structure of the userID is not an option at this ...