Fighting malware and spam

Strategies for prioritization of malicious URL re-evaluation

Onur Komili Sophos
Kyle Zeeuwen Sophos/University of British Columbia
Matei Ripeanu University of British Columbia
Konstantin Beznosov University of British Columbia

We perform a study of Fake AV distribution networks advertised via SEO poisoning that affect our customers. Using a high interaction fetcher we repeatedly evaluate the networks by querying the poisoned SEO pages. We identify means to group Fake AV networks into families using URL pattern matching, and we find that each family exhibits distinct update behaviours and sample characteristics. We identify the payload updating techniques used by each family, and show different degrees of honey client blacklisting countermeasures used by the different families. We propose optimizations to the re-evaluation logic for Fake AV networks based on these characteristics. We evaluate these optimizations and show that they can be used to reduce the required fetch frequency by X%, which in turn reduces the likelihood of being blacklisted.