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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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 ports on my router. They look like this: [DoS Attack: ACK Scan] from source: 213.61.245.234, port 80, Friday, ...
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204 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. ...
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101 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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1answer
589 views

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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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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1answer
73 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?
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1answer
104 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 ...
2
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1answer
78 views

What is this strange GET request (GET /A0A32579-2767) DoSed my apache?

I have apache behind nginx on my webserver. Today my apache stops answering to requests. Investigations shows this situation: 1) Number of apache processes grows more that 500 but MaxChildren=256 in ...
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398 views

Google: “Unusual traffic from your computer network”

I often happen to receive the message: "Unusual traffic from your computer network" while googling in Russian speaking countries. Google explains this with: You may see "Our systems have ...
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2answers
145 views

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 ...
2
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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." ...
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81 views

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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109 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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92 views

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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66 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 ...
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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 ...
0
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1answer
31 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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2answers
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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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2answers
3k views

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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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 ...
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1answer
122 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 ...
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2answers
91 views

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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1answer
201 views

Tracking IP address to prevent abuse without logging user metadata

I am trying to balance good security practices against excessive logging of user metadata / Personally Identifiable Information. I am constructing a web app that tracks IP addresses to prevent abuse, ...
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113 views

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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1answer
85 views

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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133 views

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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93 views

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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3answers
55 views

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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1answer
227 views

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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1answer
109 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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1answer
325 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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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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306 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 ...
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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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outbound ICMP allow or not [duplicate]

What is you opionion to allow outbound ICMP from the networks?? I saw many opionios on this.. on one hand is usefull troubleshooting tool on other hand many DOS attacks are based on ICMP not speaking ...
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SIP DoS classifications

I would like to understand below SIP DoS attacks Message Payload Tampering [implementation errors, SIP bugs] Flow Tampering [CPU, Bandwidth, Memory] Message Flooding [lack of authentication or ...
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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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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 ...
6
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1answer
375 views

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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75 views

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 ...
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0answers
186 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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1answer
104 views

DOS safe alternative to delay response to an attacker with sleep()?

tl;dr sleep() costs my servers resources. Using it to delay response to the attacker might cost him/her time, but allows for DOS. Is it possible to keep him/her waiting without costs of mine? Long ...
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176 views

How to force “expensive calculation” when clients connect to my server?

Page 183 of Secrets & Lies on countering denial-of-service attacks: Some researchers have proposed defenses that force the client to perform an expensive calculation to make a connection. ...
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Can someone help? I'm getting Dossed!

So basically since a few days my internet started being very slow. I checked my router logs and guess what! In the log where it is a record of DoS attacks it showed something like |Description ...
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2answers
651 views

Does Windows 7 have built in wifi deauthentication attack protection?

I'm testing a wifi de-authentication attack and it looks like my Windows 7 client is not getting kicked off the network during the deauthentication. Any explanations as to why that might be? I've got ...
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1k views

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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Ping Of Death reconstruction against a Windows 95 virtual machine

For the sake of demonstration, I'm trying to perform a Ping Of Death sent from a Kali Linux virtual machine to a Windows 95 virtual machine (vmware) on a private network. I've set both vms correctly, ...