Talos is always fascinated by the endless creativity of those who send spam. Miscreants who automate sending spam using botnets are of particular interest. Talos has been tracking a spam botnet that over the past several months that has been spamming weight loss products, male erectile dysfunction medication, and dating/casual sex websites. These are all typical products one would expect to be purveyed through spam. What interests us about this spam are some of the ways the spam is constructed to try and evade detection (a.k.a. spam filters).
Beginning in March, Talos noted an absolute explosion in the usage of link shortening services in spam. After looking into the cause we found botnet ‘unknown2250’, as it is called by the Composite Block List (CBL), to be one of the primary parties responsible for this massive increase.
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