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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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 ...
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Which IP / Client is being Ddosed?

I currently have some Vps's and shared hosting plans with a few hosting providers. Recently one of my shared hosting accounts was suspended due to a denial of service attack. I understood why they had ...
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Protection against DDoS when using proxies

We're trying to protect some sites that are primarily located in Asia using distributed caching. These sites commonly come under DDOS attacks. We are using fail2ban, but still have two problems: ...
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99 views

wordpress server visitor log contains a script, what's the risk?

I see this in my WP statistics: Is it safe to click on the link? Under what conditions will the script be triggered?
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116 views

Do the firewall hardware specifications have to be better than the network it protects?

If I need a bodyguard I'll have to hire someone whose muscles are much tougher than mine. If a server can't handle a DoS/DDoS attack because it consumes it's resources does this mean the firewall has ...
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107 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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232 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 ...
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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 ...
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What is Open Resolver Project and how does it solve DNS reflection attacks?

What is Open Resolver Project and how does it give a solution for DNS reflection attack? I also read that Open Resolver Project follows BCP38. What is BCP38?
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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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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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How to prevent DHCP Starvation attack?

All this while, I assumed that switchport security is enough to prevent DHCP dos attack. If I set it maximum 1, there can be no more mac addresses packets. But, a friend told me that using the tool, ...
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Why is it easy to detect network layer DDoS attacks?

I have seen numerous research papers that claim it is "easy to detect network layer DDoS attacks" without saying why. Usually these research papers focus on detection or prevention of application ...
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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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216 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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282 views

What is this attacker trying to accomplish?

My client is who is running a recent version of vBulletin is getting lots strange activity and I'm at a loss to explain what the attacker is trying to accomplish. The attacker registers a fake user ...
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1answer
162 views

Types of attacks outside of AppSec and Vendor-Specific Systems?

I'm reading up on the OWASP Top 10 for helping me defend my web app against common "app sec"-type attacks (SQL Injection, CSRF, etc.). And in a recent question I was prompted to not only use OWASP Top ...
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2k views

How should I configure a Citrix Netscaler to protect against HTTP, TCP, or UDP flood attacks?

I have a Citrix Netscaler and want to configure the appliance appropriately so that it can protect my hosts from a DDOS. Is this something I can do here, or must I take action on the host itself?
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CPU load of iptables to deny IPs during DDoS event [closed]

If a server has an external IP address protected with an iptables whitelist rule to reject all by default except from 3 ip addresses ip1, ip2 and ip3. If someone identifies this external IP address, ...
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124 views

How can I launch DHCP starvation attack in WLAN?

In WLAN, due to MAC association on Access Point (AP), I can't send the DHCPDISCOVER messages using random MAC addresses. But if I keep my original MAC address as the source ethernet MAC a and random ...
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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. ...
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72 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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327 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 ...
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225 views

Snort Parallelization Techniques and its effect on DDOS detection capability [closed]

I want to ask a query about snort parallelization. 1) Can snort detection rate remains same for all attacks after parallelisation? 2) As the parallelisation of netowrk traffic in each core is based ...
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165 views

Why does an overload of requests give one root access all of a sudden?

There's this saying that using a DDOS-attack, people first attack a server using millions of concurrent requests and by doing that they miraculously gain access to the server. How does this work? Why ...
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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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DDoS — null route everything not approved

Is it possible to create a route on your internet router which routes traffic unknown to null. So you basically dont even let traffic route into your firewall unless its approved? Can this help detour ...
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188 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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384 views

What can a zombie computer feasibly install and run?

I'm experimenting with a Proof of Work system that tries to force the use of a browser in order to solve the client puzzle. Basically, instead of just handing off the puzzle as hash with a well known ...
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How much does it cost to protect your website against DDOS, by tier?

Cross-posted to Quora Today several financial institutes in Israel (banks, stock exchange) were DDOSed. They decided to block all foreign IPs as a first aid measure. While I agree that it was ...
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I don't understand how BIPS got hacked [closed]

http://www.networkworld.com/news/2013/112513-bitcoin-robbery-276352.html In this story we can see BIPS got hacked, but I don't get how it was hacked when it was offline because of the DDoS.
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111 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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91 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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730 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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54 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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Can one use IP-spoofing to anonymize DDOS attacks?

Since it is possible to fake the source-ip of an ip-package, is it also possible to anonymize DDOS-attacks?
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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 ...
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How is DDoS different from DRDoS?

I understand DDoS is a DoS assault from multiple sources, where a coordinated stream of requests is launched against a target. How is DRDoS different?
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170 views

Botnet Attempting to Login to Website

Our server has recently become a target of what appears to be a botnet attack. The first indication was an insane amount of traffic to one of our client's websites - so heavy that the server entirely ...
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221 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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Is this a DDOS attack?

I lost my internet connection for about 15 minutes and I checked my netgear router log and found these 3: [DoS Attack: ACK Scan] from source: 114.77.184.189, port 44822, Tuesday, March 24,2015 ...
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418 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 ...
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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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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 ...
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316 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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255 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 ...
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195 views

What are the hardwares used to protect against a DDoS attack on Network layer

What hardware is used to prevent a DDoS attack on a network layer? This question is for my project which I am doing. I have a game server and I need to simulate an attack - an SYN flood. So what ...
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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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How to conduct DDoS attack practically? [duplicate]

Possible Duplicate: How to simulate DDoS attacks from the Internet? I want to conduct a DDoS attack. Can anyone please tell how can i conduct it? What are the latest DDos attacks? What are ...
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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 ...