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New Low Bandwidth Denial of Service Attacks
An anonymous reader writes "A paper from Rice University
appearing at the
2003 ACM Sigcomm Conference presents a new denial of service
attack where the attacker only needs to send at a low rate
to shutdown TCP flows. The trick exploits the retransmission timeout
mechanism in TCP. By sending small bursts of packets at just the right
frequency, the attacker can cause all TCP flows sharing a bottleneck
link to simultaneously stop indefinitely. And because the attacker
only needs to burst periodically, the attacker will not be
distinguishable from normal hosts. The presentation, and other
presentations from the conference, are available online (live
streaming)."
This is a tough paper to read. It's going to be a long time before an "Insightful" post.
are available online (live streaming).
This guy is an amateur, wait until he feels the slashdot effect on his server. His next presentation will be entitled, how to knock down any server by just posting an article.
My other OS is the MCP!
Actually the paper address defense mechanisms, such as randomly varying the time out interval, but it turns out that the performance lost in TCP efficiently nulls any benefits. Interesting paaper.
Good grief, they are giving instructions for how to DoS people! Arrest them using the DMCA! QUICK, BEFORE THE CAT IS OUT OF THE BAG!
ASCII stupid question, get a stupid ANSI
Gzipped Postscript file
-- Grow up and use mutt.
Anyone who is actually old enough to have used one of these would certainly know how to spell it correctly.
I call faker! You are just trying to pretend you are some 31337 old geek when you probably have never used anything slower than a DSL line.
Now get out of here before I whip ya with this here cable with BNC connectors.
My beliefs do not require that you agree with them.
Not to rain on the parade here, but I thought there were a number of more interesting papers from sigcomm this year. Namely:
- Peer-to-Peer Information Retrieval Using Self-Organizing Semantic Overlay Networks
- Quantum Cryptography in Practice
- Making Gnutella-like P2P Systems Scalable
Just some more food for thought....
"Quoting famous computer scientists out of context is the root of all evil (or at least most of it) in programming." - K
"baud" is named after J.M.E. Baudot who was French. more info
When a blimp crashed on a roof a few years ago, I always envisioned the people on the roof looking up and shouting, "Look Out! Walk for your lives!"
Hopelessly pedantic since 1963.
In the latest Lovsan.* worm outbreak, the worm was programmed to generate a DDoS attack to www.windowsupdate.com, only the attack was not very successful because that domain was just a means of redirection to the real Windows Update site (windowsupdate.microsoft.com), so Microsoft just shut it down and avoided any harm.
But with this low-bandwidth exploit, which I believe is actually not a new idea, since IE uses a tricky method to increase speed by leaving persistent connections until they time out that could be exploited, now a worm can potentially DoS any website, even dynamically selecting the target from the users' IE favorites and performing the attack very quickly (maybe in a matter of hours) without having to rely it on being a widespread, coordinated DDoS or what the target OS/Server is.
The paper even claims that in order to protect a server from this type of attack you'd need to sacrifice a good deal of performance, which in most cases is not acceptable so many people can't really afford to implement defenses. Either a clever workaround is made for this exploit, or we have tough times ahead from worm outbreaks and script kiddies.
- Otaku no naka no otaku, otaking da!!!
You had "1"s? all I had were zeros
Fix Your Own TV - RiddledTV.com Avoid the Landfill
No. Modems stopped increasing in baud at 2400, and then used various encoding methods (trellis, QAM, etc.) to squeeze more than 1 bit/baud. A 9600 bps modem, for instance, averages 4 bits/baud.
Well. Almost.
Better quality phone lines can support >2400 baud, but not by much. A 28800 bps connection is running at 3429 baud IIRC, and varying line conditions will reduce that baud rate, thus reducing your effective bps.
Compression is on top of all of this. It's an entirely different issue, and if you transfer straight text over a 28.8k modem you can get considerably more than 28.8kbps out of the modem.
You got the broad stuff right though, which is a lot more than most people grok.