Terry Zink's Cyber Security Blog

Discussing Internet security in (mostly) plain English

January, 2008

  • Terry Zink's Cyber Security Blog

    Strange legal requirements

    • 8 Comments
    Some of this stuff I couldn't make up if I tried... With all the hoopla about the David Ritz case (which I will blog about in a future post), I thought I'd remark about a very strange legal requirement about filtering mail.  As usual, this unreasonable...
  • Terry Zink's Cyber Security Blog

    Yahoo's CAPTCHA security reportedly broken

    • 7 Comments
    I read about a week ago that Yahoo's CAPTCHA security has reportedly been broken, and those of us with email accounts should be expecting an upsurge in spam from Yahoo.  To summarize the issue, before you sign up for a Yahoo account, they make you...
  • Terry Zink's Cyber Security Blog

    Some patterns for spam in my inboxes

    • 7 Comments
    I am lately seeing some odd patterns for spam in my various inboxes. In my Frontbridge account, I regularly see spam from Gmail and never Hotmail. In my Gmail account, I regularly see spam from Gmail but rarely anything else. In my Yahoo account, I regularly...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 5

    • 1 Comments
    There is yet another option I learned about yesterday. Option 3 - Provide a self-service portal Rather than quarantining outbound spam messages, provide an immediate self-service portal for users to release their message. The way it works is this: the...
  • Terry Zink's Cyber Security Blog

    Follow up - how many IPs could we potentially block?

    • 3 Comments
    This is a follow up to my previous post .  I recently looked up an old version of the PBL and decided to count up how many IPs they were blocking.  By my calculations, if we expand CIDR ranges, the PBL blocks nearly 390 million IPs. Actually...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 6

    • 1 Comments
    At this point, I hope I have made my point that the question of outbound filtering is non-trivial.  I'm not particularly keen on treating inbound mail the same as outbound mail (ie, scan, filter, deliver or quarantine) because of the time delay. ...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - Part 1

    • 4 Comments
    We are nearing the end of the dev cycle of our next release and the plans naturally start to look forward to our next release.  Don't get me wrong, there's still a ways to go in our current release.  We have to hit code complete on January 31...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 3

    • 1 Comments
    There's a great deal of discussion surrounding policy and outbound spam.  What do we do with messages marked as spam and how do we treat the organization as whole? Option 1 - Keep track of the mail disposition and cut off the entire organization...
  • Terry Zink's Cyber Security Blog

    Just how many IPs are spamming, anyhow?

    • 6 Comments
    Yesterday, one of our architects popped into my office and we had a brief discussion about blocklists.  The topic shifted to how many IPs we have banned over the years. The total number of available IPv4 IP addresses is 2 32 , or 4,294,967,296 different...
  • Terry Zink's Cyber Security Blog

    Presenting at TechReady

    • 1 Comments
    One of Microsoft's marketing events is something called TechReady.  It's an internal event for marketing to go around and learn about the various solutions that the company has.  This year, there is going to be a joint effort between Exchange...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 7

    • 1 Comments
    I thought I had laid this series of posts to rest, but instead I'm going to resurrect it for one more post. I had another meeting about how we in Exchange Hosted Services are going to implement outbound spam filtering.  I presented my slightly complicated...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 2

    • 3 Comments
    In my previous post, I mused about what it takes to do outbound spam filtering.  If customers use us for outbound mail and start relaying spam, it damages our reputation and credibility.  Ergo, we need to come up with a solution wherein we don...
  • Terry Zink's Cyber Security Blog

    Anti-spam service is not just about filtering

    • 2 Comments
    As part of a Hosted Service, sometimes I have to give credit where credit is due to other people within our department. Our latest release has a feature called Message Trace Real Time Reporting.  Basically, whenever somebody sends a message through...
  • Terry Zink's Cyber Security Blog

    Outbound filtering - part 4

    • 1 Comments
    There are other options for dealing with outbound mail.  Let's take a look at another one. Option 2 - Treat outbound mail the same as inbound mail Another option for outbound mail filtering is to treat inbound mail nearly the same as outbound mail...
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