Top posts

Every blog post that took off on Hacker News, ranked by the votes of its best submission. 4,335 posts.

Security & Privacy
Any year
2527

How random are TOTP codes?

I'm pretty sure that the 2FA codes generated by my bank's TOTP app have a bias towards the number 8 - because eight is an auspicious number. But is that just my stupid meaty brain noticing patterns where none exist? The TOTP algorithm uses HMAC, which in turn uses SHA-1. My aforementioned brain is not clever enough to…

2528

Securing Ubuntu

Table of Contents Initial Setup Setting up iptables and Fail2Ban Fail2Ban iptables rules Make shared memory read-only Setting up Bastille Linux Configuring Bastille sysctl hardening Setting up a chroot environment Securing nginx inside the chroot Extras Initial Setup Let’s login to our new machine and take some…

2529

2FA on the command line

OTP: One-Time Password TOTP: Time-based One-time Password algorithm 2FA: Two-factor authentication There is no shortage of OTP 2FA apps availiable for your phone, such as Google Authenticator or Duo Mobile. These apps take an initial secret code, and create a TOTP anytime you need a 2FA code for login.… …

2531

The RubyGems "Security Incident"

Ruby Central posted an extremely concerning “Incident Response Timeline” today, in which they make a number of exaggerated or purely misleading claims. Here’s my effort to set the record straight. First, and most importantly: I was a primary operator of RubyGems.org, securely and successfully, for over ten years. Ruby…

2542

PureVPN IPv6 Leak

Two findings in PureVPN on Ubuntu 24.04. After a reconnect the system takes a default IPv6 route outside the tunnel, and the ip6tables OUTPUT policy is still ACCEPT, so traffic leaves in the clear while the client reports connected.