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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What is the role of IP spoofing in DDoS attacks?

I've read that IP spoofing is often used in denial of service attacks, and I've also just recently read about ingress filtering, which attempts to use blacklisting to filter out spoofed IP addresses ...
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241 views

Mitigating DDOS in P2P systems

In P2P systems where performance and response times are critical individual clients are susceptible to DDOS by publicly exposing their IPs. While there are various mitigation solutions available at ...
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167 views

DDoS Attack Protection

Recently I've been threatened with an IP Address DDoS attack. I was wondering in what ways and how could I stop this attack. I'd really like to be able to do this without my parents finding out.
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122 views

Must an attacker using a Smurf attack be on the same network as the victim?

I'm learning about Smurf Attacks. Since they need to use a broadcast address, doesn't that mean they can't work over the internet? For example if an attacker sends a router the packet with the ...
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4answers
2k 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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1answer
818 views

defend against LOIC Hive Mind attack

Other than client puzzles, what are some things a website can do to defend itself against a LOIC Hive Mind attack? The Low Orbit Ion Cannon (LOIC) is an attack tool which features a user-friendly GUI ...
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748 views

What are the most popular DNS amplification attack tools for Windows and Linux?

I would like to test my edge-router firewall rules against some DNS amplification attack traffic. I could run some DNS lookup utility in an endless loop, but maybe there are some dedicated utilities ...
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70 views

How can perpertrators of denial of service attacks, determine the impact their attack has had?

Although I know how a user could mitigate Dos attacks and detect their presence e.g. checking packets received and sent, comparing current CPU usage to normal, comparing network usage to normal etc. ...
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2answers
109 views

How do DoS attacks work on non-servers?

I understand how DoS/DDoS attacks work on servers. If I have not been misled, it is possible to DoS/DDoS a system that does not act as a server, but is still connected to the internet. How is this ...
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157 views

Common attacks when no ports are open

If you have a web server with all ports closed (except, of course, the necessary HTTP) what kind of attacks can an attacker use to hack into the system? Are the only vulnerabilities stuff like ...
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2answers
128 views

What danger can come from D-DoS over VPN

Every time I use VPN, I get a message to notify me to be sure that my PC is 'healthy' from pots infections. Also I've read in this article to stay away from that. My question, what damage could ...
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44 views

Additional Protection Against DDoS

We have subscribed to an upstream ISP's protection service to protect against DDoS. I am thinking of developing a incident procedure in case my ISP's DDoS mitigation fails (highly unlikely right?). ...
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93 views

Infected employee using office VPN was part of a DDoS attack

Recently, our office VPN was taken down by our ISP after discovering a DDoS attack. Apparently an employee connected to our VPN is infected. There were no logs at the time of the event. Besides ...
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126 views

Deny IP spoof from on ASA destination

on Cisco ASA I am seeing lost of logs like following (127.108.61.90) to 190.93.249.93 on interface inside (127.30.171.61) to 190.93.249.93 on interface inside (127.105.54.108) to 190.93.248.93 on ...
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352 views

How can someone DDoS me?

If I've not opened the port 80, how can someone DDoS me? Is there a method or is it possible? Someone said that it's possible, but I'm not so sure, that's why I'm asking here.
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1k views

TCP versus UDP resilience to DDoS

I am building a service that I can implement equally well with either TCP or UDP. If I use TCP, I expose vulnerability to SYN flood and other attacks on TCP protocol. If I use UDP, it will be harder ...
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31 views

iptable ip_conntrack_max testing

I was trying to understand how ip_conntrack_max works so i have created two VM and set ip_conntrack_max to 10000 I used hping to open 10000 udp connection on VM using following command hping --udp ...
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1answer
296 views

Is a ddos attack that makes ssh auth attempts a possible way for attackers to significantly impact your system?

I'm noticing on my digital ocean server, that I'm getting a high volume of auth attempts. I don't have any passwords since I use sshe key auth, so I'm not worried about a break in. But can a ...
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1answer
299 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 ...
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3answers
241 views

How to Stop DDoS Attacks by simple function on web server?

I have an overview ideas of the preventing ddos attacks, in a simple way. Please clarify me, if my thinking is wrong. Option 1 From the basic understanding of the DDOS attacks is that the attacker ...
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0answers
33 views

Options to protect an outbound initiated connection IP?

Consider a service that has 3 separate organizations in a SaaS model. The end user(#1) connects to the first provider(#2) and then initiates a function from within the #2 that connects directly to ...
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1answer
581 views

Is it possible to force client use TCP instead UDP for DNS queries?

Assume I am managing a firewall between DNS server and clients. Is there any way to force clients use TCP rather than UDP, so we can prevent DNS spoof types of DDoS attacks?
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161 views

Protecting server from bogus HTTP Requests

What would be the recommended approach to block those typical bogus HTTP requests that the server gets bombarded with? Also has this attack/nuisance been named yet or is it generalized as Bot ...
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76 views

Ubuntu server seems compromised for a DDOS attack [duplicate]

I have this VPS Ubuntu v12.04 Server running with DigitalOcean. Zpanel/Apache/PHP stack was installed on the Server. For the past few days it was occasionally down. Initially, I didn't know what ...
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2answers
1k views

Am I allowed to DDoS my own server?

I have bought a server and used it to host some game servers or my website. Now I am visiting a computer security course and I would like to test some of the presented attacks. Am I allowed to, for ...
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206 views

2 External IPs to prevent DDoS?

In my home network I currently have a Hitron cgnm-2250 acting as a modem/router combo with an IP Passthrough option enabled for a 2nd router connected to it (ddwrt nighthawk x6 r8000). I already have ...
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44 views

Behaviour of DNS query packet

When the configured name server resolver is not reachable, the query packet will retransmitted after certain t times (in windows, every 1 seconds until 8 seconds,max). The behaviour of the legitimate ...
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85 views

Website Visited by Unresolved Ip

My Website is flooded with unknown visiters Awstats says that my website getting thousands of hits in few seconds. I am using robots.txt and .htaccess, but the problem stays there. Please help me ...
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1answer
118 views

kernel: Intrusion disconnecting me

I've read about it a little but I'm concerned. It never happened before and for last 5 hours my router gets kernel: Intrusion alerts similar to these: As soon as the kernel: Intrusion is detected, ...
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2answers
240 views

DDoS attack - where are packets dropped?

I'm researching into ddos attacks to get a better understanding. I've read lots from this community however one thing I couldn't get my head around is packet dropping. So lets say I've identified an ...
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4answers
3k views

How to mitigate SSL based DDoS attacks?

as you probably know the problem with SSL based DDoS attacks is, that the traffic cannot be analysed and filtered by a DDoS mitigation service provider such as Prolexic, Akamai, Radware, etc. without ...
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3answers
4k views

My server is used for DDoS attacks

I have webserver (centos + cpanel), and one of the clients used my server for DDoS-ing, how can I identify that client/user? What logs should I look to, is there any settings I can modify so such ...
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6answers
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Why can't we block DNS Amplification attack by blocking UDP packets or DNS response packet?

I mean if the attacker tries to ask all the open DNS resolver respond to a web server. The web server can just block its UDP ports. If the all the DNS response go to a Authoritative ...
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5answers
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Does services provided by different companies for DDoS protection work well?

Is it necessary to use any DDoS service provided by different web hosting provider and other people? We know, they are running their business to provide security to thousands of web property. They are ...
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5answers
7k 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 ...
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3answers
936 views

How does blacklisting an IP using a firewall protect against DDoS attacks?

I just read that to protecting a server against a DDoS attack involves blacklisting IP addresses. What does the term blacklisting mean? What does it mean for a firewall to drop a connection? How ...
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1answer
117 views

Different types of DDoS attacks [closed]

What is behavior of UDP flood, TCP SYN flood, Ping of Death and Smurf attack?
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105 views

VPN protection against DDoS [closed]

I am thinking of getting a VON, for DDoS protection and other various things, though what if an attacker knows my real IP already?
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5answers
3k 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 ...
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176 views

DDoS attacks targeting Android

I am currently studying some Android topics and I've been having difficulties finding answers regarding DDoS attacks. My question is: Are Android devices vulnerable to DDoS attacks or does Android ...
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16 views

Probabilistic packet marking content ID field

For Above image: All routers are using PPM. What will be the content ID field if 1) R1 = mark packet, R2= Mark packet, R3 = Not mark the packet. 2) R1 = Not mark packet, R2= Mark packet, R3 = Not ...
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1answer
160 views

What's the typical approach to caching invalid authentication attempts?

Clients (actually software pieces developed by some random dudes all over the Internet) are authenticating on a web server using "basic" authentication scheme and to do so they are passing the ...
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2answers
139 views

Hijack attacked SSL/TLS-connections?

I think we all heard the news that China used unencrypted HTTP-connections to drive DDoS attacks on targeted websites. Now within the last few months we've learned about three new attacks ...
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2answers
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 ...
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2answers
58 views

unprivileged or privileged malware for botnets

For those malwares which are used to organize botnets to DDOS a website, they just need to send and receive HTTP packets. Do they need to be privileged? If they dont need to be privileged, is it true ...
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8k views

Can someone launch a DOS attack on my IP

Suppose, I have a static IP on my PC and is known to others. None of my softwares listen for remote connection. Is it still possible for someone to DOS attack me in such cases? If yes, how it is ...
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1answer
208 views

What would a typical packet of a DDOS attack look like? [closed]

In terms of header, size and payload? We've been learning about DDOS attacks in class and they've been telling us all of the abstract ideas, but haven't told us what the actual makeup of the packets ...
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3answers
1k views

Can the IPS technology in a UTM prevent a DDoS attack?

Does a Unified Threat Management appliance (UTM) with Intrusion Prevention (IPS) enabled have the ability to prevent a DDoS attack? I have read some articles and none of them have a perfect ...
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1answer
933 views

Is there a layer 1, 2, 5 and 6 DDoS attack? [closed]

I'm doing some research on DDoS attacks, and I seem to only be finding information on layer 3,4 and 7 attacks. When I saw 3/4 and 7 DDoS attacks, I figured they were the most popular, but there were ...
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2answers
86 views

Hosting multiple websites on the same server - Prevention from DoS

I have an server which contains around 4 instances hosted on it. I am aware that if a DoS attack happens on one of the instances it will take down all the other instances too. How to prevent such a ...