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    • New note by bobjonkman 2 December 2019
      Don't worry about it. I know that's not really helpful advice, but I've had experiences like this too. I think of it as "the wheels falling off". I suspect everyone has these times, but most people won't admit it. An uplifting aphorism I heard in a movie: "It will all be alright in the end. […]
    • New note by bobjonkman 2 December 2019
      These all need illustrations for the box covers.
    • bobjonkman repeated a notice by nev 30 November 2019
      RT @nev i'm well aware canada's healthcare system is vastly inadequate, but just imagine if the housing system were anywhere near what the healthcare system was like. for-profit housing should be as obscene as for-profit healthcare. flipping houses should be seen as as unethical as hiking up insulin prices.
    • Favorite 30 November 2019
      bobjonkman favorited something by nev: i'm well aware canada's healthcare system is vastly inadequate, but just imagine if the housing system were anywhere near what the healthcare system was like. for-profit housing should be as obscene as for-profit healthcare. flipping houses should be seen as as unethical as hiking up insulin prices.
    • New note by bobjonkman 8 November 2019
      Elois and Morlocks, from another work of fiction co-opted into a user manual for the 1%
    • Favorite 8 November 2019
      bobjonkman favorited something by inkslinger: The fan theory that the Jetsons and the Flintstones are actually contemporaneous to one another -- the Jetsons' sky cities being the land of the wealthy (or formerly wealthy, perhaps, since capitalist wage relations still exist, even in a world with literal robot servants) and the Flintstones being the descendants […]
    • bobjonkman repeated a notice by inkslinger 8 November 2019
      RT @inkslinger The fan theory that the Jetsons and the Flintstones are actually contemporaneous to one another -- the Jetsons' sky cities being the land of the wealthy (or formerly wealthy, perhaps, since capitalist wage relations still exist, even in a world with literal robot servants) and the Flintstones being the descendants of the poor […]
    • Favorite 1 November 2019
      bobjonkman favorited something by ericxdu23: Hi. I'm still here.
    • Favorite 1 November 2019
      bobjonkman favorited something by hubert: ♲ @cryptpad@social.weho.st: Exactly 5 years ago at 16:42, was the first CryptPad commit by @cjdelisle, the start of a very ambitious project to restore privacy in collaboration tools. We believed in it 5 years ago and we thank the 200 supporters and 10000 weekly users from 150 countries that have […]
    • New note by bobjonkman 24 October 2019
      Best thread in a long time! nEVILle Park's ( @nev ) #Arachtober: https://social.coop/@nev/102887815460533048

Archive for November, 2009

Blacklists considered harmful

Posted by Bob Jonkman on 19th November 2009

The black hole that sucks up Internet Addresses

The black hole that sucks up Internet Addresses

BoingBoing points me to a Security Fix article by Brian Krebs called A year later: A look back at McColo on the after-effects of Real-time Blacklists (RBLs) that targeted formerly undesirable IP addresses:

The Internet community typically shuns networks known to harbor spammers and organizations that host malicious software and other nastiness, usually by including their numeric Internet addresses on “blocklists”. Many organizations configure their e-mail servers to reject messages from addresses included on one or more of these blocklists. A heavily blocklisted network quickly becomes unattractive to legitimate businesses, since any e-mail sent out of that network will most likely be refused by the intended recipients.

“The problem is once an address block gets so polluted and absorbed into all these blocklists, it’s difficult to get off all of them because there is no central blocking authority,” said Paul Ferguson, an advanced threat researcher at Trend Micro.

(“Blocklist” is a less pejorative term for “Blacklist”)

The problem is not with the (formerly) malicious site, nor with the keepers of the blacklists, or even the lack of a central blocking authority. The problem is with e-mail server admins or firewall admins who let some unpaid, unaccountable blacklist censor their incoming mail or access to Web pages.

A blacklist should be just one of the criteria used to weight the probability that an incoming e-mail message is spam, or that an http stream contains malware. When I use a blacklist I’ll take into account the blacklist’s opinion of an IP source, but I don’t want a blacklist deciding what I can or can’t receive.

It’s far more reliable to actually examine the content stream for spam or malware instead of relying on a third-party’s opinion of an IP address. Yes, this increases the transaction cost for managing spam and malware, but as these blacklist IP address areas increase there’s an ever greater chance of false positives.

Are you using blacklists? Still think they’re a good idea? Wait until your blacklist gets compromised. An attacker takes control of a blacklist, but doesn’t interfere with its regular operations. Instead, it selectively adds and removes addresses. What better way to impose a DoS attack than maliciously subscribing your target to a well-known blacklist? In fact, for the long con I can see an attacker setting up a blacklist site, and spending a year or two building a reputation. As long as system admins rely completely on that blacklist to block certain IP addresses, those system admins are vulnerable to the whims of the blacklist operator.

I also wrote about the role of blacklists in Blocking Port 25 Considered Harmful, just under a year ago.

–Bob.

(Flickr image “Black Hole” by he who shall used under creative commons license)

Posted in considered harmful, dnsbl | Comments Off on Blacklists considered harmful

Deep Packet Inspection considered harmful

Posted by Bob Jonkman on 13th November 2009

Ripe for Deep Packet Inspection

Ripe for Deep Packet Inspection

Michael Geist points us to a Sandvine report analyzing global broadband traffic.

Far more interesting than the data presented by Sandvine is the fact that Sandvine has any data to present at all. How did they get this stuff? Did they buy it from Bell and Rogers? Does their throttling equipment phone home? I don’t recall giving them permission to use my data.

They claim they’re not looking at data content. Maybe that’s true, maybe it’s not. But they’ve inspected deeply enough to know that we use more streaming applications than P2P, and more Bittorrent than Gnutella. As any data analyst knows, traffic analysis of data patterns gives as much information as the data itself. Why are they allowed to gather any of this data at all? None of their business what I use on my computer.

I’m sure Sandvine is making a hefty buck selling this report, or at least using it as evidence to sell more of their DPI equipment. They’re profiting from the the data that I didn’t give them permission to use. I think the Privacy Commissioner may want to look into this.

–Bob.

Posted in considered harmful, Deep Packet Inspection, privacy | Comments Off on Deep Packet Inspection considered harmful

 
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