English

Unpacking .zip: A First Look at Domain and File Name Confusion

Cryptography and Security 2026-04-08 v2

Abstract

The namespace for filenames and DNS names has overlapped since the introduction of DNS in 1985: \texttt{.com} was the original binary format used for DOS and CP/M systems. Recently the introduction of gTLDs such as \texttt{.zip} and \texttt{.mov}, coupled with the growing prevalence of web resources, has ignited new concerns about potential issues related to DNS and filename confusion. Thus far, the discourse on DNS/filename confusion has been piecemeal and hypothetical, making it unclear what, if any, security concerns credibly exist. To address this gap, we provide the first enumeration of how DNS/filename confusion can be abused. We then perform the first empirical case studies of DNS/filename confusion in the wild, which highlights suspected confusion across a wide range of software. Finally, based on our preliminary findings, we provide suggestions and guidance for future research on this topic.

Keywords

Cite

@article{arxiv.2604.04805,
  title  = {Unpacking .zip: A First Look at Domain and File Name Confusion},
  author = {Predrag Despotovic and Pranab Mishra and Kevin Rossel and Athanasios Avgetidis and Zane Ma},
  journal= {arXiv preprint arXiv:2604.04805},
  year   = {2026}
}