Uncovering HTTP Header Inconsistencies and the Impact on Desktop/Mobile Websites

Abner Mendoza, Phakpoom Chinprutthiwong, Guofei Gu

Abstract: The paradigm shift to a mobile-first economy has seen a drastic increase in mobile-optimized websites that in many cases are derived from their desktop counterparts. Mobile website design is often focused on performance optimization rather than security, and possibly developed by different teams of developers. This has resulted in a number of subtle but critical inconsistencies in terms of security guarantees provided on the web platform, such as protection mechanisms against common web attacks. In this work, we have conducted the first systematic measurement study of inconsistencies between mobile and desktop HTTP security response configuration in the top 70,000 websites. We show that HTTP security configuration inconsistencies between mobile and desktop versions of the same website can lead to vulnerabilities. Our study compares data snapshots collected one year apart to garner insights into the longitudinal trends of mobile versus desktop inconsistencies in websites. To complement our measurement study, we present a threat analysis that explores some possible attack scenarios that can leverage the inconsistencies found on real websites. We systematically analyze the security impact of the inconsistent implementations between the mobile and desktop versions of a website and show how it can lead to real-world exploits. We present several case studies of popular websites to show real-world impact of how these inconsistencies are leveraged to compromise security and privacy of web users. Our results show little to no improvements across our datasets, which highlight the continued pervasiveness of subtle inconsistencies affecting even some high profile websites.