Large Scale Vulnerability Scanning

Abstract

The number of services that connect to the Internet is steadily increasing. Applications integrate with each other more than ever before. As such, the possible attack surface of a given entity is ever increasing as well. Often, a single vulnerability or weakness in security can seriously undermine the security of entire systems. Other times, several flaws in tandem can prove fatal when chained together by a proficient attacker. This thesis explores the use of non-intrusive methods for vulnerability discovery. Several vulnerabilities and methods for detecting them are discussed, and a proof of concept (PoC) scanner that can detect some vulnerabilities, while still being non-intrusive, is implemented. Several methods were applied to the Alexa top 1 million sites on the WWW. And a fraction of sites proved to be vulnerable to each of the vulnerabilities the scanner scans for. This points toward the possible conclusion that even big actors on the Internet need to take fundamental security elements seriously. The so-called "low hanging fruit" is still out there; many entities’ digital security can improve considerably with simple security measures. There is no need for expensive solutions, like advanced intrusion detection systems, when one is better served focusing on the basics.