Weekly spam summary on May 13th, 2006

May 14, 2006

Unfortunately, the SMTP frontend died shortly after midnight on Tuesday morning, so some of the connection statistics are missing about 2.6 days. Given that, this week we:

  • got 11,652 messages from 229 different IP addresses.
  • handled 16,296 sessions from 808 different IP addresses.
  • received 110,313 connections from at least 35,408 different IP addresses since early Tuesday morning.
  • hit a highwater of 11 connections being checked at once since early Tuesday morning.

At the Monday morning volume timestamp, we had received 210,731 connections from at least 7,733 different IP addresses; from this I suspect that that spam storm from Saturday of last week continued full-bore on last Sunday.

Kernel level packet filtering top ten:

Host/Mask           Packets   Bytes         13422    644K       6112    305K         4554    273K          3484    173K           3397    163K         3047    151K           2692    137K         2358    118K             2309    117K           2132   99671

Overall, this is a bit more active than last week, but it's mostly driven up by a few people; there seems to have been no overall volume surge.

  • is a Hong Kong cablemodem, and was mentioned in passing last week.
  • is in the CBL. (And Canadian, alas.)
  • in in a Shaw Cable SPEWS listing. I've actually seen it in log summaries for previous weeks (although never high enough to get in this report), and it has a good looking DNS name, and it's not listed anywhere else, so I am going to whitelist it and see what happens.
  • is a covad.net 'dialup' machine.
  • returns from this April; we consider it a dialup machine, and it's also in bl.spamcop.net and the DSBL.

Connection time rejection stats:

  40201 total
  19942 dynamic IP
  16960 bad or no reverse DNS
   2033 class bl-cbl
    233 class bl-spews
    119 class bl-sdul
    118 class bl-dsbl
     83 class bl-sbl
     49 class bl-ordb
     19 class bl-njabl
      3 class bl-opm

Although this looks down from last week, the details make Sunday's spam storm pop out. All 30 of the top 30 most rejected IP addresses were rejected more than 100 times; the most active one was our friend, with 619. 27 of the top 30 are currently in the CBL, 4 are currently in bl.spamcop.net, and (123 rejections) is in SBL39408.

SBL39408 is one of those depressing SBL listings; it is for, which belongs to Vietnam Posts and Telecommunications Corp (VNN.VN). Created April 10th 2006, the two /16 halves of it are apparently the current worst and second worst /16 spam source networks on the Internet. Somehow I suspect that they are going to retain that status for a while.

Hotmail is doing much better this week:

  • one message accepted.
  • 4 messages rejected because they came from non-Hotmail email addresses (all from various non-US Hotmail domains; I really have to improve that check).
  • no messages sent to spamtraps, refused because the sender had already hit spamtraps, or rejected because of their originating IP address.

I'm willing to tentatively declare that Hotmail has fixed their problem. Besides, as far as I can tell the problem free webmail provider is now Yahoo; I am getting significant advance fee fraud spam through Yahoo from a spam gang that they haven't stopped. (The situation is bad enough that I have started blocking non-US Yahoo operations as they spam us.)

The final numbers:

what # this week (distinct IPs) # last week (distinct IPs)
Bad HELOs 448 49 405 46
Bad bounces 10 10 8 7

More than half (244 out of 448) of the bad HELOs came from btconnect.com's pool of SMTP senders in, which HELO with names like 'hesa05uker.he.local' (sometimes capitalized). The pattern for usernames in the bad bounces is fairly similar to last week, including another bounce to that 38-character hex sequence (but from a different domain).

Written on 14 May 2006.
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Last modified: Sun May 14 01:26:48 2006
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