Software Updates Strategies: A Quantitative Evaluation Against Advanced Persistent Threats

Abstract

Software updates reduce the opportunity for exploitation. However, since updates can also introduce breaking changes, enterprises face the problem of balancing the need to secure software with updates with the need to support operations. We propose a methodology to quantitatively investigate the effectiveness of software updates strategies against attacks of Advanced Persistent Threats (APTs). We consider strategies where the vendor updates are the only limiting factors to cases in which enterprises delay updates from 1 to 7 months based on SANS data. Our manually curated dataset of APT attacks covers 86 APTs and 350 campaigns from 2008 to 2020. It includes information about attack vectors, exploited vulnerabilities (e.g. 0-days vs public vulnerabilities), and affected software and versions. Contrary to common belief, most APT campaigns employed publicly known vulnerabilities. If an enterprise could theoretically update as soon as an update is released, it would face lower odds of being compromised than those waiting one (4.9x) or three (9.1x) months. However, if attacked, it could still be compromised from 14% to 33% of the times. As in practice enterprises must do regression testing before applying an update, our major finding is that one could perform 12% of all possible updates restricting oneself only to versions fixing publicly known vulnerabilities without significant changes to the odds of being compromised compared to a company that updates for all versions.

The Holy Grail of Vulnerability Predictions

“…However, in the latter case, your risk profile, i.e., the odds of succumbing, will not be better off than the company who just patches high-risk vulnerabilities, even against advanced persistent threats. 6 So why bother toiling as the hare if you fall prey to the same wolves as the tortoise? You can watch the video (https:// vimeo.com/853062910) accompanying the Communications of the ACM shorter piece 7 or read the rebuttal by Steve Lipner and John Pescatore warning against such dangerously heretical ideas.…”

Are Software Updates Useless against Advanced Persistent Threats?

“…We investigated whether this is the case in the context of Advanced Persistent Threats (APTs) [2], 'la creme de la creme' of the attacker ecosystem. APTs are sophisticated actors that deliberately and persistently target specific individuals and companies with a strategic motivation (from sabotage to financial gain).…”