Tagged Questions

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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4answers
513 views

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 ...
2
votes
4answers
9k views

Tools for performing HTTP FLOOD attack?

I'm looking for tools which can perform HTTP FLOOD ATTACK . I seached a lot and this is the only tool I've found DoSHTTP. Does anyone know another tool? I want to test them on my localhost to find ...
0
votes
2answers
256 views

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 ...
2
votes
3answers
1k views

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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3answers
14k views

What are HTTP GET/POST flood attacks?

I want to know what the main differences are between HTTP GET and POST flood attacks and mitigation strategies for both. I searched a lot but I really can't find some good articles nor examples about ...
2
votes
1answer
150 views

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, ...
15
votes
8answers
956 views

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 ...
1
vote
1answer
117 views

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 ...
6
votes
2answers
656 views

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 ...
2
votes
2answers
3k views

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 ...
0
votes
1answer
176 views

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 ...
10
votes
1answer
17k views

TCP Peer unexpectedly shrunk window messages in dmesg log

We get quite few messages like these in our dmesg log on various servers: TCP: Peer 0000:0000:0000:0000:0000:ffff:d431:5861:56369/80 unexpectedly shrunk window 2522304441:2522312601 (repaired) TCP: ...
1
vote
2answers
568 views

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 ...
6
votes
1answer
183 views

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 ...
2
votes
2answers
936 views

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 ...
8
votes
1answer
1k views

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 ...
5
votes
5answers
2k views

How does CAPTCHA mitigate DDoS attacks?

This seems like an easy question, but I've failed to find an answer. One of the uses of CAPTCHA is to cope mitigate Denial of Service attacks. Suppose an adversary performs excessive login attempts, ...
11
votes
5answers
3k 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 ...
2
votes
2answers
314 views

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. ...
4
votes
3answers
4k views

How to protect myself against paid DDoS services?

I am domestic user and I am getting attacked regularly by a guy that hates me. Here is the background story: that guy uses Skype resolvers (tools offered by paid DDoS services) to find out my IP ...
16
votes
3answers
775 views

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 ...
17
votes
4answers
679 views

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, ...
3
votes
1answer
92 views

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 ...
8
votes
4answers
3k views

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 ...
9
votes
1answer
1k views

Best way to report a foreigner attacker's ip to authorities?

I have been under attack last week and I was able to trace down the attacker and get his IP address. The attacker was located in Germany but I live out of Europe? From your experience what is the ...
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votes
2answers
189 views

Why would you want to initiate a DoS attack on a system you are testing?

What is the value of a DoS attack as part of a security assessment? this is the question asked to me in EC council's exam preparation, so need to know. not intending any attack
5
votes
4answers
967 views

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 ...
0
votes
3answers
468 views

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)?
2
votes
3answers
230 views

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 ...
1
vote
1answer
258 views

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 ...
0
votes
2answers
96 views

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 ...
0
votes
1answer
250 views

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 ...
1
vote
3answers
276 views

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 ...
1
vote
1answer
123 views

DoS and Serialization

I got the following message from Fortify static code analyser. Incorrect serialization and de-serialization can lead to unpredictable behavior and cause denial of service attacks. Can anyone ...
11
votes
3answers
7k views

Can I trust the source IP of an HTTP request?

As far as I've understood, if you try to issue a HTTP request with a spoofed IP address, then the TCP handshake fails, so it's not possible to complete the HTTP request, because the SYN/ACK from the ...
2
votes
1answer
830 views

UDP Flood Attack false positive

Symantec keeps blocking traffic from the IP of my Comcast SMC Network gateway. It blocks traffic because it is detecting a UDP Flood Attack. According to the log the CPU usage is spiking to 100% when ...
48
votes
4answers
5k views

I think I accidentally DoS'd a website. What should I do?

I was browsing a website, and stumbled across a sample scheme for password-protecting web pages. The owner of the website specifically had a page that invited people to attempt to hack it. I wanted ...
1
vote
2answers
6k views

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 ...
4
votes
4answers
4k views

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 ...
5
votes
2answers
6k views

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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vote
3answers
2k views

How does a DOS attack work when attacking a single server with a single client?

How is it possible to make a DOS attack from a single computer? Let us assume two computers, one acting as server and the other as client. Both has 100/100 mbit bandwitdh. How can then the client ...
10
votes
6answers
2k views

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 ...
3
votes
1answer
302 views

Could somebody explain connect loop DoS?

I'm trying to understand this vulnerability. How can I reproduce this?
2
votes
1answer
2k views

How do I protect my Windows computer against the IPV6 flood attack shown in this video

In the DefCon video "Three Generations of DoS Attacks (with Audience Participation, as Victims)", the speaker demonstrates how it is possible to crash a variety of devices by flooding them with IPV6 ...
7
votes
4answers
3k views

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 ...
9
votes
2answers
6k views

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 ...
2
votes
1answer
188 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 ...
5
votes
3answers
584 views

Is this a symptom of an attack (DoS/DDoS)?

I work for an e-commerce website in my country and this is the second time we suffer an attack. At least, looks like one. We have a search functionality in our website and the supposed attacker is ...
6
votes
4answers
2k views

Is this type of ARP poisoning attack possible?

I am wondering if it is possible to paralyze a network by sending out a bunch of fake ARP response packets. Some basis: I recently read a moderately detailed description of how ARP and ARP poisoning ...
5
votes
3answers
2k views

How are server overload and DoS/DDos different?

I know that server overloads are caused due to excessive number of genuine requests and DoS due to malicious request. But, my question is, if you have designed a system for Overload mitigation, does ...