8
votes
1answer
153 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. ...
5
votes
3answers
916 views

First steps in preventing DOS attacks

My server is currently being attacked from another server. This is my log: root@my-server:/var/log# tail -f auth.log Feb 19 11:53:08 my-server sshd[3745]: Disconnecting: Too many authentication ...
1
vote
1answer
434 views

Security implications of adding all domains to CORS (i.e. Access-Control-Allow-Origin: *) [duplicate]

I am curious of what all the security implications are if I set the following two HTTP response CORS headers; Access-Control-Allow-Origin: * Access-Control-Allow-Credentials: false The only ...
2
votes
1answer
841 views

TCP syn attack prevention

I am new to implementing information security. However i am trying to harden a windows server.I am using regedit to create parameters like SynAttackProtect,TcpMaxHalfOpen and TcpMaxHalfOpenRetried and ...
5
votes
3answers
4k views

How can I block an IP, if I'm getting many http requests in a second?

If some one tried force burst attack on my website, how can I block them? Ideally, I want to block an IP if I have many http/Apache requests in a second.
47
votes
4answers
4k 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 ...
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
4answers
855 views

Combat Apache Killer

Three days ago, KingCope released a simple Perl script to DoS Apache, aptly named Apache Killer. This script launches about 50 threads to request Partial Content from the server with optional GZIP ...