Thursday, April 26, 2007

Mix and Match

An additional point worth mentioning regarding IP Address Obfuscation is that the techniques can be mixed and matched within the same IP address.
All/most of these formats should work in all browsers. Additionally, in dotted format, each octet can be of the different bases. For example, 207.0x8E.0203.235 is a valid (though unconventional) equivalent to the above addresses. (Wikipedia article on IPv4)
Spammers are actively using this technique; this URL arrived today in a Pump and Dump stock spam:


The link in the email refers to, but actually redirects to a random .BIZ site.

The format of this URL is:
  1. 'Dotted Hex with leading zeroes' .
  2. 'Dotted Octal with leading zeroes' .
  3. 'Dotted Hex with leading zeroes' .
  4. 'Dotted Decimal'.
The address translates to in dotted quad (decimal) format.

1 comment:

Anonymous said...

I don't believe it. A SANS course in Maine finally, and I can't go!