林博仁 Buo-ren Lin brlin-tw

hi, i'm daniel. i'm a 15-year-old with some programming experience and i do a little bug hunting in my free time. here's the insane story of how I found a single bug that affected over half of all Fortune 500 companies:

say hello to zendesk

If you've spent some time online, you’ve probably come across Zendesk.

Zendesk is a customer service tool used by some of the world’s top companies. It’s easy to set up: you link it to your company’s support email (like [email protected]), and Zendesk starts managing incoming emails and creating tickets. You can handle these tickets yourself or have a support team do it for you. Zendesk is a billion-dollar company, trusted by big names like Cloudflare.

Personally, I’ve always found it surprising that these massive companies, worth billions, rely on third-party tools like Zendesk instead of building their own in-house ticketing systems.

your weakest link

FAQ on the xz-utils backdoor (CVE-2024-3094)

This is a living document. Everything in this document is made in good faith of being accurate, but like I just said; we don't yet know everything about what's going on.

Update: I've disabled comments as of 2025-01-26 to avoid everyone having notifications for something a year on if someone wants to suggest a correction. Folks are free to email to suggest corrections still, of course.

Background

Security Advisories / Bulletins / vendors Responses linked to Log4Shell (CVE-2021-44228)

Errors, typos, something to say ?

If you want to add a link, comment or send it to me
Feel free to report any mistake directly below in the comment or in DM on Twitter @SwitHak

Other great resources

Royce Williams list sorted by vendors responses Royce List
Very detailed list NCSC-NL
The list maintained by U.S. Cybersecurity and Infrastructure Security Agency: CISA List

https://tecadmin.net/allow-http-service-firewalld/ Written by Rahul, Updated on March 23, 2020

FirewallD is a firewall management solution for most of the Linux distributions. You can directly allow/deny ports using the service name with Firewalld. When used services name to allow/deny, it uses /etc/services file to find corresponding port of the service. This tutorial help you to open port for HTTP (80) and HTTPS (443) services via the firewall-cmd command line.

Allow HTTP/s in Firewalld

About

I faced bandwidth issues between a WG Peer and a WG server. Download bandwidth when downloading from WG Server to WG peer was reduced significantly and upload bandwidth was practically non existent.
I found a few reddit posts that said that we need to choose the right MTU. So I wrote a script to find an optimal MTU.
Ideally I would have liked to have run all possible MTU configurations for both WG Server and WG Peer but for simplicity I choose to fix the WG Server to the original 1420 MTU and tried all MTUs from 1280 to 1500 for the WG Peer.

Testing

On WG server, I started an iperf3 server
On WG peer, I wrote a script that does the following:
- wg-quick down wg0
Edit MTU in the /etc/wireguard/wg0.conf file

	#!/usr/bin/env bash

	# Copyright 2025 Amine Hassane

	# Permission is hereby granted, free of charge, to any person obtaining a copy
	# of this software and associated documentation files (the "Software"), to deal
	# in the Software without restriction, including without limitation the rights
	# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	# copies of the Software, and to permit persons to whom the Software is
	# furnished to do so, subject to the following conditions:

	#!/bin/bash

	# usage: install-wine-addon.sh { mono \| gecko }

	# keywords: wine-mono wine-gecko msi share/wine/mono share/wine/gecko

	go() {
	local pkg="$1"
	local wineexe=$(readlink /usr/bin/wine)
	# e.g. /opt/wine-devel/bin/wine

	#!/bin/bash
	# Steps:
	# 1) Make sure bash is available
	# 2) Create udev rule
	# - path to new udev rule: /etc/udev/rules.d/50-x-resize.rules
	# - udev rule content:
	# ACTION=="change",KERNEL=="card0", SUBSYSTEM=="drm", RUN+="/usr/local/bin/x-resize"
	# 3) Create /var/log/autores directory
	# 4) Create script /usr/local/bin/x-resize (this file) and make executable
	# 5) Reload udev rules with `sudo udevadm control --reload-rules`

	#!/usr/bin/env python3
	#
	# SPDX-License-Identifier: GPL-3.0-or-later
	#
	# amdgpu_metrics.py decode amdgpu metrics from sysfs
	# Copyright (C) 2021 leuc
	#
	# This program is free software: you can redistribute it and/or modify it under the
	# terms of the GNU Affero General Public License as published by the Free Software
	# Foundation, either version 3 of the License, or (at your option) any later