Does Information Security Attack Frequency Increase With Vulnerability Disclosure

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Full Title of Reference

Does Information Security Attack Frequency Increase With Vulnerability Disclosure? An Empirical Analysis

Full Citation

Ashish Arora, Anand Nandkumar and Rahul Telang, Does Information Security Attack Frequency Increase With Vulnerability Disclosure? An Empirical Analysis, 8 Info. Sys. Frontier 5 (2006). Web



Key Words

Computer Emergency Response Team, Disclosure Policy, Honeypot, Patching, Software Vulnerability, Zero-Day Exploit


Research in information security, risk management and investment has grown in importance over the last few years. However, without reliable estimates on attack probabilities, risk management is difficult to do in practice. This paper provides and interesting approach by focusing on attacker behavior, trying to understand attackers’ propensity to attack as vulnerability and patch information is disclosed. Disclosure of software vulnerability has been controversial. On one hand are those who propose full and instant disclosure whether the patch is available or not and on the other hand are those who argue for limited or no disclosure. Which of the two policies is socially optimal depends critically on how attack frequency changes with disclosure and patching.

Economic Framework

After sketching out a economic framework, the authors conclude that theoretical frameworks regarding the effect of patching on cybersecurity are inconclusive, and that the impact of disclosure and patching upon the time trends in the number of attacks is an empirical issue.

Empirical Estimates

Using a novel data set (data on security incidents and data on vulnerabilities that resulted in the security incidents), the paper goes on to provide estimates on attack propensity and how it changes with disclosure and patching of vulnerabilities. To do so, the authors empirically explore the impact of vulnerability information disclosure and availability of patches on attacks targeting the vulnerability. The results suggest that on an average both secret (non-published) and published (published and not patched) vulnerabilities attract fewer attacks than patched (published and patched) vulnerabilities. When they control for time since publication and patches, the authors find that patching an already known vulnerability decreases the number of attacks, although attacks gradually increase with time after patch release. Patching an unknown vulnerability, however, causes a spike in attacks, which then gradually decline after patch release. Attacks on secret vulnerabilities slowly increase with time until the vulnerability is published and then attacks rapidly decrease with time after publication.

Discussion and Conclusion

The general conclusion is that, in general, secret vulnerabilities get exploited fewer times than patched vulnerabilities while published vulnerabilities without patches get exploited more often. The authors also find evidence consistent with the notion that patches themselves provide crucial information to attackers and hence consider there is a need to disseminate the patches carefully, even though unless attackers expect significant delays among a substantial fraction of users in installing the patch, there would be little point in attacking. Lastly, after underlining some of the flaws of current data sets, the paper also suggests areas for future research (in particular, the authors stree the need for new and better data sources).

Additional Notes and Highlights

Expertise required: Economics - Moderate


 1. Introduction
 2. Literature
 3. An Economic Framework
 4. Data
  4.1. Extracting attack data
  4.2. Vulnerability data
 5. Empirical Estimates
  5.1. Average effect of patching and publishing: Results from non parametric analysis
  5.2. Vulnerability characteristics vs. vulnerability "fixed effects": Regression results
  5.3. Impact of elapsed patch and publish months—results of Tobit specification
 6. Discussion and conclusion