OpenVPN comes with example-scripts to update /etc/resolv.conf using “resolvconf” or systemd-resolvconf. I don’t use one of them therefore I modified the script so that it simply changes /etc/resolv.conf directly. I placed a variable “IMMUTEABLE” in this script. If IMMUTEABLE is set to 1, this script will change the fileattribute of /etc/resolv.conf to immuteable. In that way it is possible to prevent other programms like dhcp-clients to change /etc/resolv.conf while openvpn is running. I know, it’s a little bit hacky, but it works for me. The full source can be downloaded at github.com.

This year I want to send you merry christmas by creating a blog-entry for a raspberry pi christmas project. The “christmas-machine” displays merry christmas and wishes for the “christkind” on a tft display for the raspberry. It is possible to send christmas wishes using a web applications that can be accessed via wifi. I placed this installation at the coffee-kitchen in the office and it was very nice to see that my colleges had a lot of fun with it.

Blesses for “Brother Patrick” who spent me that wonderful Joy-IT TFT display.

I gave a talk at the BSides 2019 Vienna about PHP Object Injection. Here is the abstract of this talk:

Identifier: AIT-SA-20191129-01
Target: OkayCMS
Vendor: OkayCMS
Version: all versions including 2.3.4
CVE: CVE-2019-16885
Accessibility: Local
Severity: Critical
Author: Wolfgang Hotwagner (AIT Austrian Institute of Technology)

Summary

OkayCMS is a simple and functional content managment system for an online store.

Identifier: AIT-SA-20191112-01

Target: FreeRadius
Vendor: FreeRadius
Version: all versions including 3.0.19
Fixed in Version: 12.2.3, 12.1.8 and 12.0.8
CVE: CVE-2019-10143
Accessibility: Local
Severity: Low
Author: Wolfgang Hotwagner (AIT Austrian Institute of Technology)

Summary

FreeRadius is a modular Open-Source RADIUS suite.

I started this blog five years ago. In the beginning I wrote mostly articles about sysadmin and programming. Now its also filled with security related stuff. It’s fascinating for me to have a history of my interests. It’s sadly that my spare time got rare and so it happens that I don’t write much lately. My intention for the next 5 years is, to be more consequent with writing articles.

Overview

• Identifier: AIT-SA-20190930-01
• Target: GitLab Omnibus
• Vendor: GitLab
• Version: 7.4 through 12.2.1
• Fixed in Version: 12.2.3, 12.1.8 and 12.0.8
• CVE: CVE-2019-15741
• Accessibility: Local
• Severity: Low
• Author: Wolfgang Hotwagner (AIT Austrian Institute of Technology)

Vulnerability Description

GitLab Omnibus sets the ownership of the log directory to the system-user “git”, which might let local users obtain root access because of unsafe interaction with logrotate.

Overview

• System affected: Debian packages of groonga/-httpd 6.1.5-1
• Software-Version: 6.1.5-1
• User-Interaction: Not required
• Impact: Local root
• CVE: CVE-2019-11675

This year I gave a talk at the Easterhegg 2019 about a Linux kernel rootkit that can handle containers. I mainly presented my Bachelor work from 2017 with some improvements.