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 a DOS TCP packet different from normal Packet?

a normal tcp packet shown in figure How a TCP packet that causes dos attack different from normal Tcp Packet?
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Could a large amount of wget requests be viewed as an attack?

I'm working on a program that downloads and analyzes historical stock data from Yahoo Finance. I download the data in my program by using the wget command. I have a list of about 3,000 stock symbols ...
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Can/do botnets brute force “high value” users of services like Gmail?

On an intranet a login is generally disabled after a very small number of failed logins. But a public email service like Gmail can't do the same, otherwise pranksters would just be continuously ...
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DoS by consuming all hosting trafic

Given a small website hosted on a small data plan, is it possible for someone to keep doing requesting for my website URL or just an image hosted on my website that will consume all my permitted ...
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Mitigate DDos on Windows box

I would love to know, If you know some way to mitigate DDos/Dos attacks on Windows. In Linux we can Mitigate using the IPTables Almighty, but I wonder If there is something like that in Windows. ...
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DoS on an ordinary IP [duplicate]

So, I understand DoSing to an HTTP Server. I understand Layer 7 DoS attacks and how to even make these work. But what for an normal IP that isn't HTTP and is connected to the internet. Is the only ...
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How does HTTPS help websites under DoS attacks

From time to time one of the websites I browse regularly becomes a victim of a DoS/DDoS attack and usually they solve the problem by switching to https. I cant see the connection between the attack ...
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168 views

Slow HTTP DoS Mechanics

Our firewall detected and blocked a Slow HTTP DoS the other day. There were only a few attempts in the log. It wasn't a full on attack (there would be more traffic). My question is...if I'm an ...
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63 views

Locking an enterprise account from an internet facing application

Some corporate applications are most useful when they are accessible from the internet. Outlook Web Access comes to mind. Those application usually have a user directory (usually LDAP) in the ...
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94 views

Is it possible to build a web-service which is immune to DOSes?

I heard that a service I'm using on the web has some problems with denial of service -attacks. I was wondering if it is theoretically possible to build a web-services where user can send data and ...
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How to send GET/POST requests without header and agent information

I want to test our DOS prevention system against http requests that are not have header and agent information. Is there any tool I can do that. I tried siege with this command siege -c 3 -b -H ...
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Preventing artificial latency or “Lag Hacking” in multiplayer games

There is an attack that some people have dubbed "lag hacking", and its gaining popularity in multiplayer games. There are at-least two ways of creating artificial latency. One method of introducing ...
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210 views

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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How can I stop this DOS attack?

I have this entry appearing constantly in my router logs: [DOS Attack] : 5 [RST Scan] packets detected in last 20 seconds, source ip [xx.xx.xx.xx] They just never stop. It doesn't seem to affect ...
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Is it safe to ignore DoS attacks on my router?

There are several entries in my router's log file showing recent DoS attempts on some of its ports. They look like this: [DoS Attack: ACK Scan] from source: 213.61.245.234, port 80, Friday, November ...
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How could a SYN flood affect a home router

I was curious how a DoS attack would affect a home router. In particular, I'm interested in how a SYN flood would affect a home router. The reason I'm interested is due to a Cisco document I read. ...
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773 views

HTTP attack taking down PHP-FPM [closed]

Someone started attacking my site a few minutes ago and its caused PHP-FPM to max out all cores (4) on my vps and NGINX is now serving 502 to all users. I'm seeing a bunch of these requests with tons ...
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How web application firewalls protect application from DDoS attacks?

How to protect a web application from DDoS by the implementation of Web Application firewalls? How effective is this method?
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Can this be a DoS Attack?

When I'm checking my log, I found like 15k events of " PAM service(sshd) ignoring max retries; 6 > 3 " I know this might be normal, and considered as Brute-Force attack, but can it be classified as ...
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distinguish between bots and legitimate clients [closed]

If an attack (DoS & DDoS) involves thousands of bots, how can the server distinguish them from legitimate clients?
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Can the attacker launch a sufficiently large SYN flood to overwhelm the victim's server?

Suppose that the victim's web server infrastructure can process 200,000 TCP connection requests per second. Assume that a single connection request (TCP initial SYN) requires 40 bytes to transmit. The ...
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How to detect bots clicking a link?

I own a url shortening service. I want to deliver only legitimate statistics to my clients. There are possible scenarios that a particular user writes a script to automatically open the shortened URL, ...
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How does a Distributed Denial Of Service Attack work

Let's assume that a hacker has already infected an X number of PCs , each one of them is online. How will he actually perform this attack? Just send ping requests or use his very precious tool to do ...
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Is opening a new mysql connection for each query potentially unsafe?

I am doing some unit testing and noticed that if I click (or have multiple people clicking) the same filter very very fast (very precise I know;) eventually I get a "The connection is already open." ...
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Does a self-signed certificate offer more protection than a public key?

I'm having a hard time finding the practical benefits of transmitting a self-signed certificate over simply a public key. I understand that a self-signed certificate proves the integrity of the public ...
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De-auth attack Reason codes and possible reaction

I am learning about Deauth attacks and how they work. I see that the Deauth frame has a reason code which indicates the reason for the deauth. I have tested the attack with aircrack-ng and this reason ...
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Could John Oliver be (inadvertently?) launching DOS attacks?

Occasionally on his show, John Oliver points his viewers to the comments section of websites for companies/organizations that have done something putatively nefarious. For instance, when he pointed ...
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Whose resources does Maltego Footprint L3 exhaust? Mine or target's?

Maltego Footprint L3 says: This perform a level 3 (intense) footprint on a domain. It takes a while and it eats resources. Use with care. Whose resources do they refer to? My resources or the ...
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844 views

What is DDOS TCP KILL?

I've recently been introduced to Kali Linux's webkiller tool, located in the websploit category. It works on the concept of Tcpkill. I don't understand how the DoS attack with Tcpkill works. Can ...
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162 views

How can I protect my “try it with one click” service?

I have a service with "try it now" experience that currently offers a "one click" effort. This service has a pool of N resources (lets say 50). Each new resource takes about 1 hour to generate. ...
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do ISPs implement security measures?

For example, if a user is receiving a denial of service attack, with huge amounts of packets being sent to him to disrupt his service, will the ISP notice and stop the offending traffic? Another ...
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Preventing a Computational DoS Attack in Public Key Cryptosystems

I'm designing a server which accepts anonymous messages using ECIES: as in, anonymous users send the server an ephemeral EC public key, and the server uses ECDH to derive a shared secret, and some KDF ...
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Does clicking lead to DoS attack? [closed]

I have a website. Suppose someone will code a program that will click continuously on the links of my webpage: could this lead to a DoS attack ?
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API Key DDOS prevention method

Hi I just wanted some feedback on a DDOS preventing php script that I'm designing. It quite simple and I wanted some feedback on whether you guys think it would be effective. I'm currently using the ...
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what type of attack does LOIC do? [closed]

I have used LOIC (Low Orbit Ion Cannon) earlier . Today i was reading on wikipedia that there are many types of dos attacks , namely SYN attacks , HTTP flooding ,UDP flooding ,etc and two questions ...
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How to prevent Cookie-Bombs?

Egor Homakov made a nice writeup (Cookie Bomb or let's break the Internet) on how to crash CDNs and other websites with cookies. Although this is a user/browser-side DOS, I'm wondering how one would ...
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How can I test a DoS attack against snort?

I need to set up an scenario where an attacker DoS attacks port 80 of an server while snort and others users try to connect to port 80 at the same time. Something like this: 1000 connections to port ...
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Wordpress: Thousand of mail sent to my site from an unknown user! Site is near to be blacklisted by Google

Recently an employee of mine developed a website in WordPress. Things were all fine until we received an email from Google , notifying me that some stuff that can really create security issues is ...
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how to block ip from head or ping or get or post to webserver (using apache and windows)?

am using apache 2.4.9 latest with windows 7 i am using some modules like limitipconn_module security2_module but using wireshark i get unlimited request to busy my webserver (DOS) from some ip ...
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What type of attacks will a SMTP server face if it does not have ratelimiting while sending mails?

Assume a web site with some kind of mailer option, that doesn't implement any rate limiting: This enables users to send an unlimited amount of email per second. Will SMTP face possible DoS attacks ...
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Active Directory - Denial-of-Service [duplicate]

How can I prevent a user on the domain from launching a denial-of-service attack against Active Directory by scripting bad password attempts against every user in the domain?
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OWA + AD Lockout Policy: Quite the Mixture

Many organizations have webmail exposed to the world. These sites are often hooked up to AD for user authentication. Are there any specific security controls OWA (Outlook web app) has that would ...
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Security considerations in concurrent applications

I have been building a network application with a Client/Server model, where a central server handles multiple client threads. I did my best to ensure that no matter what context the program is run ...
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Are my Snort rules correct?

I am trying to do a Snort demo and I though it would be nice to detect a real threat. I picked the sasser worm and the jolt/teardrop dos attacks for the demo; no particular reason. Out of the three ...
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How To Protect Tomcat 7 Against Slowloris Attack

I'm using Apache Tomcat 7 to run my webapp on Linux. I scanned it by Acunetix and it's telling me that my webapp is vulnerable to "Slow HTTP Denial of Service Attack". How can I protect it? Acunetix ...
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369 views

Root/Naked domain and DDOS

Some services like Github has DDOS mitigation measures for their root/naked domain, but not other subdomain(s). What so special about the root domain concerning the DDOS attacks? [1] ...
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Akamai or Incapsula (or other) for CDN with DDoS Protection? [closed]

One of our clients is launching a new site and I've been tasked with making a short overview of the advantages/disadvantages of Akamai, Incapsula or other CDN providers who are strong with DDoS ...
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How to avoid DDOS against Kerberos Authentication Server

I have a school project where i am supposed to implement a Kerberos based infrastructure (AS, TGS and resource server). It is already done and working, but i started thinking about how to protect the ...
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Harden a server against mass SSH DoS attacks

How can a Linux server be protected against an attacker that tries to open a large number of SSH sessions (probably trying to brute force a password) that no ports remain to be able to legitimately ...
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Using pattern matching to make a port more secure

I am planning to make a web application deployed on a port more secure by detecting the pattern of the request an then comparing it with the patern next time that IP tries to connect.Any ways to move ...