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    • New note by bobjonkman 9 July 2022
      New Zealand #ProportionalRepresentation
    • Favorite 9 July 2022
      bobjonkman favorited something by blacksam: What country do Canadians threaten to move to when they don't like election outcomes? #politics #canada
    • bobjonkman repeated a notice by blacksam 9 July 2022
      RT @blacksam What country do Canadians threaten to move to when they don't like election outcomes? #politics #canada
    • New note by bobjonkman 5 July 2022
      Congratulations to Dr. Cooley, and to you! And welcome to Canada!https://twitter.com/SNOLABscience/status/1542562373193633793 I saw the news on Twitter, and said to myself "Hey, I know that person!" It's amazing how familiar we humans feel with each other using only social media...
    • bobjonkman repeated a notice by steve 5 July 2022
      RT @steve Spring Cleaning, Except its Packing to Move to Canada https://steve.cooleysekula.net/blog/2022/07/02/spring-cleaning-except-its-packing-to-move-to-canada/
    • Favorite 5 July 2022
      bobjonkman favorited something by steve: Spring Cleaning, Except its Packing to Move to Canada https://steve.cooleysekula.net/blog/2022/07/02/spring-cleaning-except-its-packing-to-move-to-canada/
    • New note by bobjonkman 26 June 2022
      I've never played #Minecraft - Is this #Federated software? Is it #FreeSoftware? If so, how can Microsoft control what's happening on someone's private server? Even if such code existed in a #FreeSoftware application, I would have thought there'd be a fork that eliminates that external control. It's time for that now. But if #Minecraft isn't […]
    • bobjonkman repeated a notice by lnxw48a1 26 June 2022
      RT @lnxw48a1 Seen via @sullybiker https://freeradical.zone/@thenewoil/108539077382008407 Microsoft bans in #Minecraft will soon carry over to privately run servers as well. One commenter said "Seems like there is a really simple solution here: Don't be a toxic asshole on a public server." But once $CORPORATION starts interfering with privately hosted servers in any way, those servers' […]
    • New note by bobjonkman 27 May 2022
      Mind you, there's something charming and soporific about listening to a professional baseball game with an old-fashioned, laid-back announcer. But most of those have retired... #ASMR
    • New note by bobjonkman 27 May 2022
      Applies to all professional #Sportsball: begging to see overpaid drug-users doing something that the rest of us would gladly do for free. When I walked our dog we'd pass the local baseball field, and we'd stop and watch the game for hours. But the one time I went to a professional baseball match (Toronto Blue […]

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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