As long as the client sends header data at a rate of 500 bytes per second the server will wait up to 40 seconds for the body of the request to complete. Apache will wait 20 seconds for body data.As long as the client sends header data at a rate of 500 bytes per second the server will wait up to 40 seconds for the headers to complete. Apache will wait 20 seconds for header data.This configuration is doing the following: The configurations above are a suggested starting point but you may need to tweak the individual settings to best suit your setup. RequestReadTimeout header=20-40MinRate=500 body=20-40MinRate=500LimitRequestFields 100LimitRequestFieldSize 8190LimitRequestBody 102400LimitRequestLine 4094TimeOut 60ListenBacklog 1000KeepAliveTimeout 5 In the reqtimeout file paste the following content: This is a configuration file that will be preserved after any upgrades since it is in the custom folder.Ģ. Windows: C:\Program Files (x86)\Common Files\Aspera\Common\apache\custom\nf.Linux: /opt/aspera/common/apache/custom/nf.Look fora file named reqtimeout at the following location and open it in a text editor: You can check your version of Common by running the following command:ġ.
#Block slowloris attack upgrade#
If you prefer not to upgrade you will need to add the reqtimeout module yourself. If you have an earlier version of Common we encourage you to upgrade for added security benefits.
Now insert the IP address to be blocked on the first position in the rule. If you are using a Linux system it is very easy to do so. In order to prevent this kind of attack you can use Apaches reqtimeout module to configure the timeout process for HTTP requests.Īs of Common 1.1.25 for Faspex and Common 1.2.20 for Console the reqtimeout is included by default. One of the simplest ways to mitigate Slowloris DDoS attacks is to block the IP or port of the attacker. This means that an attacker can send multiple incomplete GET requests and keep the connections open in order to block other users from getting their requests processed by the server.Īpache does have a default timeout of 300 seconds after which it stops waiting for incomplete HTTP headers and closes the connection but since the timeout is reset once the client sends more data an attacker can just continue to send garbage data and keep the connection open. The attack exploits the fact that Apache waits for complete HTTP headers to be received before closing an HTTP connection. This means that your Apache web servers for Faspex or Console are vulnerable to this attack (applications based on nginx such as Shares are safe). A Slowloris or Slow HTTP DoS attack is a type of denial of service that can affect thread-based web servers such as Apache.
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