apache servers attacked by slowloris attack

#Apache servers attacked by slowloris attack how to
#Apache servers attacked by slowloris attack code

Slowdos attacks can actually be used on some versions of Nginx (up to v1.5.9) or badly configured Nginx for that matter, but in practice it is unlikely. I could say “just use Nginx”, and I was planning to do so as well, but then I would not be totally honest. Apache on the other hand, will often yield under the high pressure from such an attack.

Thus, it is very unlikely to slowdos a Nginx based server as it is made to handle a lot of concurrent connections.

We have to appreciate the fact that Apache was made in an era where most had no idea how big and powerful the internet were going to be.

#Apache servers attacked by slowloris attack how to

The sole reason why Nginx exist is to solve the C10K problem, which is the problem of how to optimise network sockets in order to handle a large number of clients at the same time. In comparison to Apache, Nginx is newer (19 respectively). The connection will thus be open and after a while maxing out the maximum connections allowed. The slowloris attack exploit how Apache work by taking all the connections that are spawned by for example mpm_prefork or mpm_worker by sending incomplete requests. The mpm_worker module is multi-threaded, in comparison to mpm_prefork, which makes it quicker to run on the server.

#Apache servers attacked by slowloris attack code

For example, mod_php cannot be used with mpm_worker which is an Apache module capable to parse and execute PHP code inside Apache itself, a common way to run PHP under Apache. It also depends on what other modules you use with Apache. Which MPM one would use depends on what content you are serving. Administrators can thus swap out its connection handling architecture easily, if they so choose to. To understand why that is a problem, one has to understand how Apache in works and how it differs from Nginx.Ĭlient requests are handled by three multi-process modules (MPMs). You exploit the issues Apache has with serving many users at the same time. The idea of the attack is relatively quite simple. I could just present the Python or JavaScript that does this, but I find it useful to understand how this vulnerability is allowed to exist. It probably makes everything a bit easier to understand. Mike Pound’s Computerphile video about slowloris first. It does not only affect Apache Flask, a Python based web server, is also possible to attack in a similar manner. It is called a “slow and low DoS”, or simply “slowdos” or “slowloris”. One thing I do know, however, is that there is a pretty funny denial of service (DoS) attack that can be done to Apache-based web servers from even a small Raspberry Pi. I don’t even remember why I started using Nginx I just did. # minimum request/response speed (deny slow clients blocking the server, ie.Why don’t I use Apache for my web server? Is it because Nginx is newer than Apache? Is it because it handles concurrent connections “slightly better” than Apache? No, not really. # disables keep-alive when 70% of the TCP connections are occupied:

# maximum number of active TCP connections is limited to 256 # handles connections from up to 100000 different IPs LoadModule qos_module /usr/lib/httpd/modules/mod_qos.so Put the following file inside nf and restart apache Affected servers will keep these connections open, filling their maximum concurrent connection pool, eventually denying additional connection attempts from clients.Ĭonfigure mod_qos to prevent Slowloris DDOS on Apache 2 Periodically, it will send subsequent HTTP headers, adding to-but never completing-the request. It accomplishes this by opening connections to the target web server and sending a partial request. Slowloris tries to keep many connections to the target web server open and hold them open as long as possible.