This post describes different software components involved in host name resolutions and DNS configuration on GNU/Linux systems. It consists of a diagram and some accompanying explanations. The goal is to give some pointers and references to understand how to troubleshoot host name/DNS resolution problems and configuration problems on GNU/Linux systems.
Some guidance about configuring/fixing domain name resolution with a corporate Virtual Private Network (VPN), especially OpenVPN and with systemd-based Linux systems. This configuration uses the internal/private corporate resolvers for resolving internal/private domain names while using the ISP resolver for general domain names. This might help if your VPN is struggling these days because of the COVID-19 threat 😷.
I thought I was understanding pretty well how bash argument processing and various expansions is supposed to behave. Apparently, there are still subtleties which tricks me, sometimes.
Remote code execution via cross site request forgery in InternetCube and YunoHost
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How I found remote code execution vulnerabilities via Cross Site Request Forgery (CSRF) on the administration interfaces of InternetCube applications and of the YunoHost administration interface which could have been used to execute arbitrary code as root. These vulnerabilities were fixed in YunoHost 3.3, OpenVPN Client app 1.3.0. and YunoHost 3.4.
More example of argument and shell command injections in browser invocation
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In the previous episode, I talked about some argument and shell command injections vulnerabilities through URIs passed to browsers. Here I am evaluating some other CVEs which were registered at the same time (not by me).