Rapid7 Vulnerability & Exploit Database

Slowloris Denial of Service Attack

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Slowloris Denial of Service Attack



Slowloris tries to keep many connections to the target web server open and hold them open as long as possible. It accomplishes this by opening connections to the target web server and sending a partial request. Periodically, it will send subsequent HTTP headers, adding to-but never completing-the request. Affected servers will keep these connections open, filling their maximum concurrent connection pool, eventually denying additional connection attempts from clients.


  • RSnake
  • Gokberk Yaltirakli
  • Daniel Teixeira
  • Matthew Kienow <matthew_kienow[AT]rapid7.com>


Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':

msf > use auxiliary/dos/http/slowloris
msf auxiliary(slowloris) > show actions
msf auxiliary(slowloris) > set ACTION < action-name >
msf auxiliary(slowloris) > show options
    ...show and set options...
msf auxiliary(slowloris) > run 

Time is precious, so I don’t want to do something manually that I can automate. Leveraging the Metasploit Framework when automating any task keeps us from having to re-create the wheel as we can use the existing libraries and focus our efforts where it matters.

– Jim O’Gorman | President, Offensive Security