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Attack On a Significant Flaw In Apache Released

Posted by kdawson on from the take-it-slow dept.

Zerimar points out a significant flaw in Apache that can lead to a fairly trivial DoS attack is in the wild. Apache 1.x, 2.x, dhttpd, GoAhead WebServer, and Squid are confirmed vulnerable, while IIS6.0, IIS7.0, and lighttpd are confirmed not vulnerable. As of this writing, Apache Foundation does not have a patch available. From Rsnake's introduction to the attack tool: "In considering the ramifications of a slow denial of service attack against particular services, rather than flooding networks, a concept emerged that would allow a single machine to take down another machine's web server with minimal bandwidth and side effects on unrelated services and ports. The ideal situation for many denial of service attacks is where all other services remain intact but the webserver itself is completely inaccessible. Slowloris was born from this concept, and is therefore relatively very stealthy compared to most flooding tools."

3 of 203 comments (clear)

  1. Boring by Anonymous Coward · · Score: 5, Insightful

    Talk about a boring exploit: no chance for expanding the attack into anything other than a DOS, and if it becomes widespread enough, fairly trivial to fix... (just kill the oldest waiting client that does not have a full header when the last client is taken.) I'd be embarrassed to publish something like this....

  2. Seems to be a general problem. by Z00L00K · · Score: 4, Insightful

    And the only resolution right now that I can see is to have a connection timeout.

    At least the problem is a denial of service problem and not a problem with intrusion so the damage is easily rectified - restart the web server. Not that you really want to restart it.

    And I suspect that other services can be vulnerable to this type of attack too, not only web servers.

    --
    If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
  3. Re:Why not IIS? by Malc · · Score: 5, Insightful

    Does the HTTP spec say anything about the server application timing out the connection? Seems like reasonable behaviour to me. I would be surprised if this isn't a configurable option in Apache too.

    People love to hate it, but IIS has matured in to a very good web server. It's my choice over Apache.