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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5answers
4k views

How do major sites prevent DDoS? [duplicate]

As far as I know, I have never heard of or seen any large scale web sites like Amazon, Microsoft, Apple, Google, or Ebay ever suffer from DDoS. Have you? I have a personal philosophy that the bigger ...
0
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0answers
30 views

DNS Amplification attacks [on hold]

For an academic paper,I need to simulate a DNS amplification attack and show how it can be mitigated.How to go around simulating a DDOs attack,because I don't have zombies at my disposal and I don't ...
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3answers
472 views

Can anyone DDOS my server with jmeter? Do they need a powerful server for that?

Is there a way to DDOS my web app through jMeter? Can anyone DDOS with a simple PC? I couldn't find any answer here. I would appreciate if anyone could help me out.
0
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1answer
46 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 ...
0
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0answers
44 views

Unsuccessful TCP amplification, how do I get amplification? [closed]

We are doing a research project on TCP amplification, and have so far been unsuccessful. We have have spoofed packets but have not seen amplification (the packets are successfully being reflected). ...
4
votes
2answers
197 views

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. ...
2
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1answer
53 views

Downloading operating systems vulnerable to TCP amplification

I am doing a security research project on TCP amplification, and was looking to download vulnerable OS's for testing. From what I have researched mostly ancient linux kernels (2.0.x and below) and ...
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2answers
30 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 ...
3
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2answers
77 views

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?
0
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1answer
102 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 ...
0
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1answer
72 views

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?
-1
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1answer
80 views

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 ...
14
votes
7answers
28k 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 ...
2
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3answers
156 views

Distributed Denial Of Service Attack Mitigation

Is there any way in which you can stop a DDoS attack(or any measure that you can take), if the packets sent by the attacker look like normal traffic? I got the question on an interview (how would you ...
2
votes
4answers
1k views

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, ...
2
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0answers
96 views

cisco asa syn flood detection and response not working

I have a Cisco ASA 5510 (ASA Version 8.3(2)) that has been getting a syn flood attack on it (or more accurately through it - targeting a host behind it) a couple of times a day for the past few days. ...
3
votes
1answer
295 views

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 ...
2
votes
3answers
86 views

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." ...
2
votes
0answers
63 views

Ubuntu server seems compromised for a DDOS attack [duplicate]

So 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 ...
0
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3answers
107 views

Questions about ddosing?

Suppose a website is hit by a 500 Mbps DDos, and then the DDos stops for a second or so; does the website recuperate?
6
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3answers
2k 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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votes
1answer
132 views

How to prevent ddos and brute-force attack by restricting IP's on Wordpress website

I want to make wp-login.php and/or wp-admin accessible only from one country. If I want wp-login.php access only from USA then my approach from .htaccess is like below <Files wp-login.php> ...
0
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1answer
571 views

Strange flood of requests to my web server

About an hour ago, strange requests began showing up in my access logs. They are coming in at a rate of ca. 400 req/s and appear to come from IPs all over the place. It started out at a lover rate and ...
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votes
1answer
91 views

Why do I target the proxy server if I send a DDoS attack from it?

I once read that if I send a DDoS attack via a proxy (for example with LOIC), I won't target the server I am trying to send a DDoS attack to but I will actually DDoS the proxy server. Most important ...
0
votes
1answer
65 views

Identifying attacks by network activity

Is it posible (and how) to tell from a network dump if there is a buffer overflow attack, DoS or brute force attack? A DDoS would be more obvious to identify, but those attacks mentioned above I think ...
0
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0answers
31 views

DOS attack to increase packets received from a single request?

Is there any attack out there that can be implemented where a single request to a server i host for example responds by sending the same file say 20 times back ? the idea behind the attack is to DOS ...
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3answers
227 views

How to identify if my site is vulnerable to DOS/DDOS attacks? [closed]

I am hosting a site on a hosting server. How to identify whether my site is vulnerable to DOS/DDOS attacks?
3
votes
1answer
469 views

Are voluntary / manual DDoS illegal?

Since DDoS is simply a group of subjects coming together to send requests to a particular server, is it true to say that a voluntary DDoS is perfectly valid and legal in US? By that, I mean that a ...
2
votes
2answers
164 views

Will a DDOS attack prevent outbound traffic?

Imagine a scenario where there is a DDOS attack against a target - clients would be unable to connect to the target, but I would like to know if the target could initiate a connection to the outside, ...
0
votes
2answers
762 views

A DDOS attack by uploading a few hundred large files - whats stopping anybody?

I am new to the IT Security field and am essentially a developer as opposed to a networking person hence the question may be a dumb one I am writing a REST service exposed to the internet which ...
0
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1answer
239 views

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 ...
0
votes
1answer
121 views

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 ...
0
votes
2answers
118 views

Solution for traffic capturing from router

i'm a newbie and i'm having a problem that i can't find it by google. I'm researching abbout DDoS detecting method now. As we can see that nowadays people often analyze networking traffic from router ...
1
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6answers
467 views

DDOS slow-http attack prevention

I am often getting DDOS attack from multiple IPs with simple HEAD requests. There are around 30 unique IPs creating such attacks. 201.230.167.68 - [05/Jan/2014:00:19:19 +0530] "HEAD / HTTP/1.1" 301 ...
2
votes
2answers
1k views

Outbound DDOS attack from a centos server

We run a mail server (postfix/dovecot/centos 6.4). The hardware is based on a supermicro chasis with IPMI features. It also runs a web interface for accesisng mails(Apache web server ) Recently our ...
1
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1answer
107 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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0answers
305 views

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 ...
4
votes
2answers
2k 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 ...
11
votes
2answers
2k views

How to test against DDoS in a controlled enviroment?

Can you suggest me methods or tools that can help in simulating a DDoS attack in a controlled enviroment (like my private lab)?
6
votes
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
votes
5answers
15k views

How to simulate DDoS attacks from the Internet?

The idea behind security tests is easy. You want to know what a hacker can do - you hire a security expert who acts like a hacker to see how far he can get. You want to know what an evil admin can do ...
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2answers
206 views

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 ...
15
votes
3answers
1k views

NTP DDoS Attack on Home Servers

After some half-good script kiddies found out about this exploit or DDoS method, they have been doing it like crazy to websites, game servers, and now my home servers which allows me to work on some ...
3
votes
2answers
879 views

Blocking incoming traffic from privileged port (< 1024) to mitigate DNS DDos Amplification attacks

Hope someone can clarify. As I understand, in a DNS DDos Amplification attacks Multiple DNS queries are sent to a vulnerable name server with the source IP spoofed to that of the target server. The ...
-2
votes
1answer
722 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 ...
2
votes
1answer
376 views

Lots of failed outgoing sshd attempts. Am I hacked?

For the last two days I've been seeing lots of lines in my /var/log/auth.log that look like: sshd[xxxxx]: error: connect_to 0.gravatar.com port 80: failed sshd[xxxxx]: error: connect_to ...
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3answers
694 views

Strange Apache access logs

A site of ours has been targeted by some kind of strange attack and I am trying to work out exactly how it has happening. Basically, the strangest thing is that the logs seem to correspond to entirely ...
2
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0answers
185 views

DoS stress test not working [closed]

First off I'd like to say this is my first post on StackExchange, so please let me know if there's anything wrong with it. Also, I don't know much about networking and I'm just making a simple java ...
1
vote
1answer
108 views

DNS zone size overload?

Is it possible to DOS DNS by creating custom dns zones with lots of text records in them so that the size of the DNS zone is in the order for example 100 Gigabyes, and then query all the dns records ...
0
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1answer
136 views

What packet parameters should be checked to detect layer-7 DDoS attack?

What packet parameters should be checked to detect layer-7 DDoS attack (http flood, slow http request etc.)? Do window size and packet timeline show enough information to detect attack traffic from ...