Questions tagged [ddos]

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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1answer
42 views

Calculate pps for DDoS evaluation

I am working on a task where I have to evaluate how much throughput one can generate in packets per second. I know I can send them as fast as possible with hping3 [...] --flood, but is there a way to ...
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1answer
136 views

Can we prevent DDoS or spam form submission with client authentication?

There is a public query form in my web app, and architecture team asking to authenticate the web app with OAuth2 like this, but I don't believe it will be of any help. I believe best way to protect ...
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45 views

.htaccess File Changed - Question About Possible Breach Or Default Defense Mechanism

Today I got reports about one of my websites becoming inaccessible. I've come to learn that at the time we were under DDOS attack. After getting through that, the website started throwing a ...
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69 views

Does a DDOS attack on an application using CDN have to first bring down all the involved CDN servers to affect the application's availability?

CDN are said to absorb and mitigate the Denial of Service and DDOS attacks. Consider an application that uses a CDN provider to deliver its content. So if an attacker tries to bring down such an ...
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2answers
98 views

Can someone perform DDoS on my VPS even if it is only accessible through SSH?

Can someone perform DDoS on my VPS even if I have not installed any webserver software like apache, nginx, etc.? Since I have not installed any webserver software, it's not really available to the ...
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1answer
164 views

What's the limiting resource that makes DDoS attacks possible?

I often see DDoS attacks compared by network traffic, for example: The biggest DDoS attack to date took place in February of 2018. This attack targeted GitHub, a popular online code management ...
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1answer
80 views

Protect Wordpress against ddos attack [closed]

The above screenshot is from my website's cpanel visitors list.My website is build on wordpress. And I think someone is trying hard to crack open my website with DDOS attack and drain out my 10gb ...
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What are spammers trying to acheive who only provide the correct contact information in their spam? [closed]

I've recently received 2 spam SMS messages, claiming to be from 2 different organizations, but (obviously) not sent by them. However, all of the contact details in the SMS match the real details of ...
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2answers
196 views

How does a CDN actually prevent DDoS attacks, when an origin server accepts direct connections?

I am trying to understand how a CDN (like Cloudflare e.g) does protect against a DDoS attack. I would think that the internet traffic is routed through a CDN's reverse proxy, then filtered. This ...
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2answers
194 views

How to protect Authentication API from a DDoS attacks?

After Login, severs can check authorization, tokens etc at API and WAF levels to mitigate DDoS attacks. But this can only happen after user has logged in. How can we protect DDoS attack on login API? ...
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130 views

How do attackers hit a website with thousands of similar but distinct IP addresses?

I have a website that is being hit with invalid URL requests by thousands of distinct IP addresses, never the same one used twice. Most of them are in a few ranges of IP addresses and often just go ...
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1answer
45 views

UDP amplification: length(response_packet) < length(request_packet)

I was researching the GitHub DDoS attack of 2018, in which memcached UDP amplification was used. I noticed that a GitHub blog post referenced a CloudFlare post which described memcached-based UDP ...
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32 views

Fundamental difference in security research in Cloud platform VM and normal machine

I am trying to study the effects of various network based attacks in an Openstack Cloud environment that I have setup with few machines. However, what would be the fundamental difference between a VM ...
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4answers
139 views

DDoS implication on your network?

DDoS attack can be used to infiltrate your network for attackers to try to exploit the machines in the inner network ? Or it just attack that meant to disrupt the daily operation of a Network.
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1answer
71 views

Is it possible to DDos a http wan filterd router? [closed]

Like the service is there but it's just filterd enabled for lan access only .. what will happen ?
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1answer
1k views

My router is getting port scan attacks [duplicate]

My internet suddenly cut out yesterday, i checked the router and it looked like nothing is wrong. I looked at the logs and i see this 2019-08-18 12:50:39 Security Warning Detect UDP port scan ...
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2answers
174 views

How do I prevent traffic on my site from a source other than Cloudflare?

I use Google Cloud Platform to serve the site I manage. I have one load balancer there, which controls the movement to several virtual machines. When I came across the problem of DDOS attacks on ...
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1answer
41 views

Rate limiting API with PBKDF2 challenge?

Assume I have a public API endpoint which I'd like to protect against abuse. I'd like to implement a solution that ensures that the client spends some computational time before allowing the request to ...
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118 views

Unkown attack on linux server wordpress website

I have a WordPress site. Recently under a serious DDoS attack. For this WordPress site I use nginx, varnish and apache in the backend. A part of access log shows this: 24.41.213.36 - - [23/Jun/...
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2answers
95 views

What's the main constituent part of botnet?

Is the botnet controlled broiler of servers or personal PCs? We know the botnet can be controlled to DDoS attack, but what's the main constituent part of botnet? I know the botnet's element maybe PC,...
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1answer
132 views

Why is GRE tunneling is needed when having a BGP based solution against DDoS?

I understand that GRE tunneling is very handy when sending the data back to the client after scrubbing because it's designed to ensure that the data is sent reliably by initiating a private point-to-...
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3answers
146 views

What can be done against DDoS attacks when I just have only small number of “known” clients reaching a server?

Description of the Situation: Let's say 1000 "known" clients/workers are collecting time-sensitive data from the field and sending to a server. Therefore, we need to secure the server from DDoS ...
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2answers
288 views

Why were hyperlink auditing pings used for DDoS attacks and not any other requests?

A few days ago this new story has been published: Researchers have found that the HTML feature called hyperlink auditing, or pings, is being used to perform DDoS attacks against various sites. This ...
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1answer
140 views

Cloud based solution to prevent DDoS attack on multiplayer game server?

I built an architecture below: How does it work (and if it's possible) Assuming your game server currently runs on Node 1 and then Node 1 gets a successful DDoS attack. Your cloud system has ...
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1answer
182 views

519 tls handshake attempts in 3 seconds, with 415 within one second, was this a DDOS attack?

This morning our webserver was unresponsive to say the least. The connection was lost, the database connection we have was sluggish to say the least. I was forced to do a reboot via the remote hosting ...
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1answer
260 views

a mysterious & pointless long-term hacking attempt?

It seems that I am the target of a mysterious ongoing hacking attempt. I have several domain names, most of which are currently parked & pointed at a single ‘main’ website. For the last couple ...
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1answer
488 views

Thousands of 28000 “no pg_hba.conf entry for host” logs from Postgres - is this an attack?

Since yesterday afternoon my production Postgres database hosted on Amazon EC2 has been logging thousands of errors (averaging one or two per second) that all follow the format: sql_error_code = ...
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4answers
531 views

Public API security: authentication vs. rate limiting etc

We are raising a SaaS product that allows businesses to setup and orchestrate selling of a certain class of goods/services. This product has an API in its core and an ecosystem of various apps around ...
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27 views

Which metrics can be considered in the context of DDoS-similarity analysis?

What data should be collected if i want to bind two different DDoS-attacks? In example i want to build a model, which will calculate the similarity of two DDoS-attacks. The basic metrics should be: ...
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1answer
414 views

How did facebook DDoS me?

About 1 day ago my router was being DDoS by some people and one of the ip addreses was Facebook's. Can anyone explain this? [DoS Attack: ACK Scan] from source: 31.13.65.50, port 443, Saturday, ...
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4answers
2k views

What is the difference between an SYN-Flood attack and an SYN-ACK-Flood attack?

What is the difference between an SYN-Flood attack and an SYN-ACK-Flood (SYN Reflection) attack?
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1answer
121 views

How does IP traceback works? [closed]

In part prompted by the difficulties in determining the true origins of DDOS attacks featuring spoofed IP addresses, researchers have attempted to develop the concept of IP traceback: determining ...
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1answer
72 views

Blockchain + shared unused bandwidth as the proxy front = ddos mitigated?

Pentesting the new webapp that we have developed before having an external source have a go at it and give us a risk assessment. Now we have come to the portion right at the end; DDOS. For the most ...
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1answer
269 views

How fill up a gig interface bandwidth with hping3?

I've been trying to test our software against DOS attacks. So, I used 'HPing3' but it just fills up 10-11M of my interface's bandwidth! I ran the tool 40 times, I mean 40 hping3 processes, ...
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2answers
171 views

Please help diagnose multiple incoming packets

We have an internet-facing router and it is significantly slowed down. We investigated the network traffic and came up with following information: All the packet size is same (i.e. 40 bytes) All ...
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2answers
191 views

Website is behaving strangely - was it attacked?

Our website was behaving strangely. Sometime it was down and nothing was accessible. Sometime it started loading but pages browsing was too slow. We checked apache logs and found the below ...
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1answer
329 views

Do major ISPs still ignore IP spoofing?

I was reading this question: Why don't ISPs filter on source address to prevent spoofing? and based on those answers, ISPs ignore it because of the overhead of checking for spoofing. But that ...
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1answer
88 views

How link flooding DDoS attack remain undetected?

I read some explains or paper about link flooding DDoS attack, which is new relatively. For example "employs legitimate, low-density flows to flood a group of selected links. Therefore, these ...
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1answer
522 views

Nginx: mod-security rule for http slow DoS attack

The only related rule in mod-security for slow DoS is modsecurity_crs_11_slow_dos_protection, and it's for Apache only. Is there a rule for Nginx?
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1answer
125 views

Firewall Showing 1,000's Of Strange GET Parameters Being Sent To Login Page?

So I woke up today, and checked my Firewall Events on CloudFlare for my website like I do normally. Most of the time I'll just see thousands of failed SQL injection attempts, but this morning I was ...
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3answers
385 views

Suspicious “100% guaranteed” web hosting security package

Notes: I have very limited knowledge and experience in this field. My boss does not want to spend a penny more that what we already paid for. The website has a form that sends a message to our email ...
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1answer
280 views

Why the DDoS attacker need many zombie machine for attack? [duplicate]

Why the DDoS attacker need many zombie machine for attack? if attacker has one machine for generate enough attack traffic for its business(DoS), does it still need many zombie machine(DDoS)? what's ...
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3answers
3k views

Threshold for DDOS Attack

I am trying to understand and simulate SYN Flood DDOS attacks. I am using snort to give me alerts. While I have control over the rate for my testing, I am interested in knowing what a good estimate of ...
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3answers
335 views

Is it possible to defend against a backscatter attack?

Yesterday, some spammer on the other side of the world decided to send out a ton of phishing mails with my business mail address as both From address and envelope sender. The usual best practices are ...
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0answers
112 views

Will More vCPU's and RAM Help Protect Against Some Smaller Scale DDoS Attacks?

Obviously having more vCPU's (virtual CPU's) and more RAM by them self won't be able to alone help stop and/or prevent a DDoS attack, but let's say after a DDoS attack is finished and/or slowing down ...
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1answer
602 views

Amazon EC2 Abuse Report

My company recently received an email from Amazon which notified us of malicious activities occurring on our running EC2 Instance. The email states: We observed machines under your control ...
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1answer
682 views

Can I assume that an empty user agent will always be a robot?

I want to prevent robots flooding my website and I'm thinking about a ban in these cases... Can I assume that an empty user agent will always be a robot?
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3answers
770 views

How to detect when one or more devices in my local network have become DDOS attack nodes?

I have a home network, big family, with around 20 devices on it at any given time. It seems like every year or so, some device gets a virus or a security flaw is revealed, and the device starts ...
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4answers
731 views

Most reduced types of DoS attacks

As I understand it, there are generally only two common types of Denial of Service attacks in regards to the OSI model: Network-Layer-DoS (NLDoS) on layers 3, 2 or 1. Application-Layer-DoS (ALDoS) on ...
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1answer
135 views

TCP protocol Denial-of-service attack [closed]

There are different types of DDoS attacks. As defined by TechTarget, Network-centric or volumetric attacks overload a targeted resource by consuming available bandwidth with packet floods. Protocol ...

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