Questions tagged [denial-of-service]

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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1answer
149 views

How can one securely hash passwords server side while avoiding DoS? [duplicate]

It is generally recommended that one use a slow hash function to hash passwords. However, does this create a DoS risk?
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1answer
295 views

Are there any risks to matching user-supplied regex against user-supplied inputs?

I have an IRC bot written in python3 that parses user requests for search and replace. Is there any risk of DoS or other attack by doing this?
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1answer
137 views

What other attacks can be deployed using IP spoofing other than DoS(and DDoS) attacks ?

I want to know the other attacks which are associated with IP spoofing because, we're trying to implement Source Address Validation (SAVA) and wanted to where else can Source Address validation ...
4
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1answer
459 views

How to defend against a Spoofed-IP Blacklist DOS attack?

So I've implemented an IP Blacklist for the /login endpoint on my server. If any IP fails to login more than x number of attempts in x number of minutes the requesting IP is blacklisted for x number ...
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2answers
428 views

Can an ISP or webpage block me from accessing it if I'm sending too many requests? [closed]

I visit webpage where there is a comment section. These comments have a number of likes/dislikes as 2 numbers. If I vote, a cookie is created and I can't vote again (but I can if I delete my cookies, ...
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1answer
795 views

How to test DOS attacks through Router?

One of my clients has been told by their ISP that a DoS attack has happened and they have provided the logs of Juniper router. What is the criteria in routers on which we can confirm DoS attack is ...
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2answers
116 views

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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2answers
106 views

Should I really treat memory leaks like classical bandwith dos?

I recently found that a big company use an outdated product in their file-storage servers (I got the hidden name and version). The bug is corrected in recent version, but they weren’t any cve or ...
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1answer
1k views

How effective are firewall rate limiting rules for slowing down brute force and DOS attacks?

I am investigating methods to slow down the rate at which attackers can make brute force attempts against my webserver's SSH and HTTP services. I have come across many articles as well as the iptables-...
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1answer
2k views

Can a Cisco ASA 5505 block this DDoS attack?

Since more than a week ago, my dedicated server (located in ovh.com) has been under TCP SYN (I think) attack. OVH don't care about it but this attack is killing my server with a high CPU load (...
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1answer
276 views

Netgear WNDR4300 crashes when port scanned

I have no idea what is going on here, I'm leaning towards an error in the firmware or some kind of protection they wont let you turn off. My router has 2 networks: a 2.4ghz and a 5ghz network. I see ...
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2answers
545 views

DoS Reflection attack using CharGen protocol

I'm researching DoS Reflection attacks w/ amplification, and Wikipedia says that one of the "worst" amplification services is the Character Generator Protocol. Frankly, I have never heard of this ...
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1answer
193 views

Denial of Service during scanning [closed]

As I know you can do Denial of Service when footprinting with scanners, like nmap or Maltego. But is it legal? As I know, scanning isn't illegal but doing DoS attacks is. EDIT I meant if you scan ...
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1answer
494 views

DHCP Exhaustiation / Rogue DHCP interrupted by real DHCP NACK

I was trying to run a Rogue DHCP Server which should cause a MITM attack. I did the following Exhaust the real DHCP Server using DHCPig (worked) Run a Rogue DHCP Server using the auxiliary/server/...
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0answers
143 views

Router reporting DoS-Attack from rival provider

In my (netgear) routers logs there are entries like the following, often multiple times a second since quite some time. [DoS Attack: RST Scan] from source: 80.218.64.172, port 10646, Tuesday, ...
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1answer
486 views

Initial handshakes of attacks via client-initiated renegotiation

As far as I understand after reading this beautifully explained answer, MiTM data injection attacks via client-initiated renegotiation can only happens if the attacker is already in a connection with ...
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5answers
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DoS in local network computer

I'm using Snort to study detection, and I wanted to simulate a DoS attack from the inside to another computer in my home network, but I have a question. If I start to flood the target computer with ...
4
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2answers
774 views

Reverse-proxy not a solution to DDOS attacks when hosted on PaaS?

We run our apps on Heroku and use Cloudflare as a CDN and to protect against DOS attacks. However, we recently experienced (a relatively minor) attack that managed to easily bypass Cloudflare by ...
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3answers
3k views

New denial-of-service vulnerability in TLS protocol, based on shooting down other users' sessions?

I think I have a new denial-of-service attack on TLS, and I'd like you to check whether this is a real vulnerability. I recently learned about the proper way to drop an authenticated client session (...
1
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1answer
546 views

Strange IP's on my firewall log

Check the screenshot of my router firewall log below, I can see traffic originating from strange IP addresses to my public address. What are these? I've just setup this router few hours ago, am I ...
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1answer
865 views

Is there an easy way to know if a regex is “evil”

I was reading this article (about ReDos). The examples they give are pretty simple but I'm sure such regex can hide everywhere. If there is any way to test if a regex is evil without spending a lot of ...
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4answers
330 views

Is 100% anonymity possible with Tor under certain circumstances? [duplicate]

Tor has guidelines that define a set of rules/techniques to assure anonymity. Some examples are browsing in small window mode so your screen resolution can't be detected, using HTTPS everywhere, and ...
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2answers
2k views

UDP flood from my machine, or false positive?

The company that hosts my dedicated server has alerted me to what they think is malicious traffic coming from my machine. They supplied me with graphs showing a large amount of UDP traffic coming from ...
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2answers
723 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 Activity?...
5
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1answer
552 views

What are the mitigating factors for CVE-2015-5364?

CVE-2015-5364 describes a UDP based DoS vulnerability in the Linux kernel that can be used to deny processing cycles to the host operating system and its applications. https://access.redhat.com/...
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1answer
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Random scanning or potential attack/recon? [duplicate]

If the purpose of a SYN Flood attack would be to make the target unresponsive to normal traffic, same as any other DoS, wouldn't this attack generally have been directed at a public server rather than ...
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1answer
7k views

Secure Client-Initiated Renegotiation - DoS DANGER

I tested my server against cryptographic attacks and I have a few major and minor issues. However I would like to know how can I mitigate and protect against such vulnerability warning: Secure Client-...
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2answers
4k views

How long does it take to execute a DoS attack on a PC using the ping… -t CMD command?

Suppose the target of a Denial of Service attack is a PC on LAN with IP 192.168.1.10. Then, I can continue to ping the target by running the ping command in an infinite loop in CMD, that is, by ...
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2answers
512 views

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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3answers
3k views

How can I defend against malicious GET requests?

My server is getting hit with a variety if requests like the following: Started GET "/key/values" ActionController::RoutingError (No route matches [GET] "/key/values") Started GET "/loaded" ...
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1answer
248 views

Recommendations for SMTP DoS [closed]

I have an opened SMTP server that allows me to send emails. The problem is that I can send a massive amount of emails (80,000+) to a specific mailbox and block all the other legitimate emails (that ...
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2answers
2k views

DNS Server Recursive Query Cache Poisoning Weakness “Bounce DoS”

Tenable Nessus states that if there is a DNS Server Recursive Query Cache Poisoning Weakness the host allows recursive queries via UDP, then the host can be used to 'bounce' Denial of Service attacks ...
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2answers
393 views

Deny attacker access to my router

I was experiencing very low connectivity on my wireless, so I checked the router logs. Here's what I saw: Jul 09 11:07:24 Per-source ACK Flood Attack Detect (ip=74.125.130.129) Packet Dropped Jul 09 ...
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1answer
548 views

HPKP-based persistent denial-of-service attack on web sites

HTTP Public Key Pinning (HPKP) is a standard that allows a HTTPS website to specify which certificates it trusts, and instruct the browser not to allow any connection to that site that's secured by ...
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2answers
7k views

How to prevent smurf attack?

I am using college network to access internet. Many other users are using the same network. Recently I have been experiencing sluggish net connection. So when I did some investigation, I found that ...
4
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2answers
13k views

How to mitigate UDP flood attacks?

My friend linked me some website where you pay $5.00 / m and get access to a plethora of 'dos stresser' tools that offer udp flooding, and other malicious flooders. It's a web-based system and you ...
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4answers
957 views

What are the drawbacks of login request throttling?

In a web application, one way to protect against password guessing attacks is to lock out accounts after a set number of failed logins. This could be done on both source IP address and username. For ...
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9answers
11k views

Can attackers get anything with DoS attacks except crashing the service?

A DoS (short for "denial of service") attack is a form of attack used on web services which aims to "crash" the service. Is there any motive of this form of attack besides crashing the service / ...
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2answers
2k views

How can the Android GraphicBuffer::unflatten() vulnerability (CVE-2015-1474) be exploited remotely?

I've been reading up-on DoS (denial-of-service) attacks within android and although I understand attacks like the below, which make use of regular programming functions etc. (Android Web Browser) ...
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0answers
207 views

What to do if I accidentally DoS a site? [closed]

A few weeks ago I was non-maliciously using a website with server-side calculations when curiosity got the better of me and I decided to mess with some GET request values. I expected the site to give ...
10
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2answers
4k views

Is there any protection against malicious devices on a CAN bus?

CAN (controller area network) is a bus used in all modern cars. You can read a lot of the cars information over this bus and I think (but I'm not too sure about this) that some critical control ...
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1answer
4k views

Is there a layer 1, 2, 5 and 6 DDoS attack? [closed]

I'm doing some research on DDoS attacks, and I seem to only be finding information on layer 3,4 and 7 attacks. When I saw 3/4 and 7 DDoS attacks, I figured they were the most popular, but there were ...
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1answer
312 views

Is there an exploit for python hash collision? [closed]

Is there an exploit for this vulnerability? EDIT Python DoS via hash algorithm collision - oCERT advisory 2011-003. Affected numerous languages. No CVE for Python but CVEs for other languages.
4
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1answer
589 views

RSnake's Slow Loris tool

I was looking at RSnakes implementation of his Slow Loris done on perl which can be seen here. I set up a little server to listen to his packets, and at first found this GET / HTTP/1.1\r\nHost: David-...
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2answers
110 views

Requesting webpage as DOS

Is it possible to launch a DOS by repeatedly requesting a webpage (refreshing)? Like holding down F5 on your browser?
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1answer
41 views

Is there some kind of a local DoS against processes?

Is there an attack that somehow floods a target process (e.g. by repeatedly calling a WinAPI function that involves the process) and thereby crashes or temporarily disables it?
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1answer
469 views

Organizing results from netstat using find on Windows [closed]

I am trying to figure out a way to natively do this within Windows without having to load any 3rd party applications. When I run: netstat -ba I want to find established connections without losing ...
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2answers
485 views

Is radio burst transmission really “jam resistant”?

Quoted from here: Certain military communication systems are based on the jam-resistant burst transmission of binary telegrams which consist of orthogonal spread-spectrum waveforms (BOK). To ...
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1answer
1k views

Slow Loris Incomplete GET Request

A slow loris attack is an attack of incomplete GET requests to most famously an Apache server because the server does not timeout the connection made after extremely long periods of time, from my ...
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2answers
394 views

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 19:...