not too long ago i published a post called understanding malware growth in which i observed that the period of accelerated malware growth we had seen in previous years appeared to be over. unfortunately, according to new av-test.org statistics (as reported by mcafee) accelerated malware growth is back.
now one way you could take that is that i was wrong. perhaps i was, at least with regards to being optimistic - perhaps optimism was not called for. i wasn't wrong about the rapid expansion being over, though, the growth was more or less constant for the better part of a year. that is a distinct departure from the growth trend prior to august 2007. a year is a considerable amount of time for malware to languish.
another point i don't think i was wrong about was the nature of malware growth itself. if you read the previously mentioned post carefully you should have come away with the impression that, contrary to the naive malware growth forecasts, malware growth is punctuated. there was very clearly a point at which the rapid expansion of malware growth started, and just as clearly there was a point where that expansion came to an end, a point where whatever driving factor was resulting in the higher malware production rates had finally reached it's peak and the malware ecosystem returned to a kind of balance.
i had in mind the possibility that another disruption in malware growth could occur - if it can happen once it can happen again, but i didn't mention it because i didn't want to be negative, i didn't want to jinx our collective good fortune. had more up-to-date data been available, however, i would have known our good fortune had already come to an end when i wrote that post.
another disruptive event does appear to have occurred. continuing with some of the postulates from the previous post (namely that the mechanism for creating the bulk of the variants is server-side polymorphism), if we were to then go with the postulate that the web is the dominant malware delivery vehicle (as opposed to malware being carried directly in email or some other channel) then one of the key limiting factors in the automated creation of new minor variants is the problem getting victims to view malicious content.
there are 2 things in recent memory that i think could have lead to more browsers loading malicious content than before. one of those things is innovation in the field of social engineering - we've been seeing more fake celebrity news (especially deaths) recently than i seem to recall seeing in the past. hammering on a new hook that the public at large hasn't yet grown wise to could result in an increase in the success of social engineering that used that hook and thus trick more people than usual into browsing to malicious content.
the second thing that could be contributing to an increase in browsing malicious content is the increasing trend of mass website compromises through SQL injection. increasing the number of legitimate sites that serve malware (even if indirectly) increases the chances of web surfers stumbling across malicious content entirely by accident.
both of these things can lead to an increase in the browsing of malicious content, which in turn gives the server-side polymorphic engines responsible for handing out that content the opportunity to create that much more of it in an automated fashion. that said, both of these things will also reach a peak in their influence. the public will eventually grow wise enough to the fake celebrity death reports that the success rate of that ploy will drop back down to previous levels. successful sql injection will also eventually taper off as the content management systems being targeted get hardened by their vendors, or as the pool of potential victims shrinks when the entities in it realize they need to take steps to prevent this sort of compromise.
when these things happen malware growth will once again plateau (it might already be there, but it's far too soon to tell) - until the next disruptive malware innovation, that is.