Giovanni Grieco GiovanniGrieco

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

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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

Pandoc Setup

Description

A simple setup for Sublime to jot down notes in Markdown and compile a nice PDF with LaTeX through Pandoc conversion.

Why? Markdown is quick and easy to write, LaTeX is more of a hassle. But LaTeX produces nice PDFs. Using Pandoc, you can utilize the best features of both worlds by writing in markdown and compiling PDFs with LaTeX, with a simple one-click in your editor. This works fairly well for simple documents and pandoc supports most of Markdown syntax, in addition to supporting a range of variables set in a YAML meta block. Did I mention that it also supports writing LaTeX-style math and other LaTeX-commands in your Document? (Like this: $e^{i\pi}+1 = 0$ )

The output PDF is a A4 paper with 12pt font and 1 inch margins. It uses fancyhead to style the header and footer with date, pagenumbering and title/author. (This can be changed in your Pandoc-settings)

Create Root CA (Done once)

Last update: Nov 2025.

Create Root Key

Attention: this is the key used to sign the certificate requests, anyone holding this can sign certificates on your behalf. So keep it in a safe place!

openssl ecparam -genkey -name secp384r1 | openssl ec -aes256 -out rootCA.key

Run sudo vim /etc/default/grub
Find GRUB_CMDLINE_LINUX_DEFAULT
Append video=hyperv_fb:[the resolution you want], for example: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=hyperv_fb:1920x1080"
Write the changes, quit Vim
Run sudo update-grub
Run sudo reboot

h/t https://blogs.msdn.microsoft.com/virtual_pc_guy/2014/09/19/changing-ubuntu-screen-resolution-in-a-hyper-v-vm/

README

Services declared as oneshot are expected to take some action and exit immediatelly (thus, they are not really services, no running processes remain). A common pattern for these type of service is to be defined by a setup and a teardown action.

Let's create a example foo service that when started creates a file, and when stopped it deletes it.

Define setup/teardown actions

Create executable file /opt/foo/setup-foo.sh:

A simple Ghostscript command to merge two PDFs in a single file is shown below:

gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=combine.pdf -dBATCH 1.pdf 2.pdf

Install Ghostscript:

Type the command sudo apt-get install ghostscript to download and install the ghostscript package and all of the packages it depends on.

	USER= # your user account
	rm /run/media/$USER/__/etc/systemd/system/graphical.target.wants/initial-setup-graphical.service
	rm /run/media/$USER/__/etc/systemd/system/multi-user.target.wants/initial-setup-text.service
	mkdir /run/media/$USER/__/root/.ssh/
	cat /home/$USER/.ssh/id_rsa.pub >> /run/media/$USER/__/root/.ssh/authorized_keys
	chmod -R u=rwX,o=,g= /run/media/$USER/__/root/.ssh/

	#!/usr/bin/env bash

	mac_address=$1
	# Strip colons from the MAC address
	mac_address=$(echo $mac_address \| sed 's/://g')

	broadcast=$2
	port=4343

	# Magic packets consist of 12*`f` followed by 16 repetitions of the MAC address

	function Send-UdpDatagram
	{
	Param ([string] $EndPoint,
	[int] $Port,
	[string] $Message)

	$IP = [System.Net.Dns]::GetHostAddresses($EndPoint)
	$Address = [System.Net.IPAddress]::Parse($IP)
	$EndPoints = New-Object System.Net.IPEndPoint($Address, $Port)
	$Socket = New-Object System.Net.Sockets.UDPClient