Weekly spam summary on December 9th, 2006

December 10, 2006

Our SMTP frontend crashed and restarted three times this week, twice on Wednesday around 6pm and the third time today at 3:16pm, so some of our stats are really fragmentary. Still, this week we:

  • got 15,036 messages from 272 different IP addresses.
  • handled 20,984 sessions from 1,243 different IP addresses.
  • received 114,833 connections from at least 33,061 different IP addresses up to Wednesday at 4am, received 92,925 connections from at least 27,804 different IP addresses from Wednesday at 6pm until Saturday at 4am, and received 11,972 connections from at least 5,107 different IP addresses since 3:16pm today.

This appears to make connection volume around the same as last week. For the days that we have decent per-day stats, connections are running around 38,000 to 40,000 connections a day, with around 10,000 to 11,000 different IP addresses added per day.

Kernel level packet filtering top ten:

Host/Mask           Packets   Bytes         28527   1712K          16263    846K          15633    938K         12648    607K        6435    386K            4551    273K         4357    261K          4176    200K           3892    187K         3480    209K

Things are up from last week overall.

  • is the centrum.cz mail servers, justifying their new permanent block.
  • is terra.es, returning from October and many, many previous appearances.
  • and kept trying bad HELO greetings.
  • is still a PacBell DSL line.
  • and both kept trying to send us stuff that had already tripped spamtraps.
  • is in the CBL.
  • has invalid reverse DNS and is in APNIC space; we require APNIC IP addresses to have valid reverse DNS.
  • is a wanadoo.co.uk machine, which has wound up being in SPEWS again and has appeared here before.

Connection time rejection stats:

  58045 total
  33557 dynamic IP
  19569 bad or no reverse DNS
   3319 class bl-cbl
    210 class bl-sdul
    190 class bl-dsbl
    104 class bl-spews
     89 class bl-njabl
     76 cuttingedgemedia.com
     42 class bl-ordb
     27 class bl-sbl

This week saw some really prolific connection time rejection sources. 13 of the top 30 most rejected IP addresses were rejected 100 times or more, with the champion being (1,124 times, all in a few minutes around 6pm on December 3rd, with enough activity that it triggered our per IP address maximum connection limits). After that we drop to (201 times), (172 times), and so on.

In other stats, 22 of the top 30 are currently in the CBL, and 5 are currently in bl.spamcop.net.

Here's a table of the SBL hits:

Connections SBL listing comments
9 SBL45324 a /24 ROKSO listing for Expedite Media
5 SBL39631 a spam source in .cz (listed March 29th)
4 SBL47687 a spam source (listed October 27th)
2 SBL48728 reasonably long-term spam source
2 SBL48020 a /27 ROKSO listing for Howard Minsky (listed November 3rd)
1 SBL48694 a /24 of spammers
1 SBL48348 a /24 ROKSO listing for 'livemercial.com' (listed November 17th)
1 SBL46756 A ROKSO listing for William Stanley; apparently it is an open squid proxy being used by this spammer (listed September 18th)
1 SBL41737 a spammer's mail sending machine (listed May 10th)
1 SBL41344 a /21 listing for a spammer's web hosting (listed May 17th)

It's interesting that this time around there's not a single advance fee fraud spam source on the list. If I'm really lucky, this means that (SBL-listed) advance fee fraud spam sources are cleaning up their act, but I suspect that it is more likely that spammers are learning to not bother using SBL-listed free webmail systems.

This week, Hotmail had:

  • 1 message accepted.
  • No messages rejected because they came from non-Hotmail email addresses.
  • 27 messages sent to our spamtraps.
  • 1 message refused because its sender address had already hit our spamtraps.
  • 3 messages refused due to their origin IP address (one from Nigeria, one from the Cote d'Ivoire, and one from Burkina Faso)

And the final numbers:

what # this week (distinct IPs) # last week (distinct IPs)
Bad HELOs 785 146 1059 155
Bad bounces 109 95 109 101

The first_last female Slavic names staged a huge comeback this week, although they don't quite make up a majority of the bad bounces; it looks like that honor is captured by the random alphanumeric jumble login names.

(One amusement in all of these stats is watching a single first name be associated with a run of last names, for example 'alisa petrova', then polkyakova, then osipova. I suspect that this is just brute force table merging of first names and last names.)

Written on 10 December 2006.
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Last modified: Sun Dec 10 00:31:00 2006
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