Securing OpenSSH keys with hardware-based authentication (FIDO2)

Passwordless authentication with OpenSSH keys has been the de facto security standard for years. SSH keys are more robust since they’re cryptographically sane by default, and are therefore resilient to most bruteforce atacks. They’re also easier to manage while enabling a form of decentralized authentication (it’s easy and painless to revoke them). So, what’s the next step? And more exactly, why would one need something even better? Why? The main problem with SSH keys is that they’re not magic: they consist of a key pair, of which the private key is stored on your disk....

April 9, 2022 · 5 min · Wonderfall

Docker & OCI: a humble hardening guide

Containers aren’t that new fancy thing anymore, but they were a big deal. And they still are. They are a concrete solution to the following problem: - Hey, your software doesn’t work… - Sorry, it works on my computer! Can’t help you. Whether we like them or not, containers are here to stay. Their expressiveness and semantics allow for an abstraction of the OS dependencies that a software has, the latter being often dynamically linked against certain libraries....

March 30, 2022 · 19 min · Wonderfall

F-Droid: how is it weakening the Android security model?

F-Droid is a popular alternative app repository for Android, especially known for its main repository dedicated to free and open-source software. F-Droid is often recommended among security and privacy enthusiasts, but how does it stack up against Play Store in practice? This write-up will attempt to emphasize major security issues with F-Droid that you should consider. Before we start, a few things to keep in mind: The main goal of this write-up was to inform users so they can make responsible choices, not to trash someone else’s work....

January 2, 2022 · 23 min · Wonderfall