T Schaffner tschaffner-te

cheatsheet

Emulating a Raspberry Pi with QEMU

Goal: Emulate a Raspberry Pi with QEMU in order to run the Raspbian O/S (based on Debian Linux).

The current setup is not ideal. For one thing, the maximum RAM allowed using the "versatile-pb" firmware is 256 Mb. In addition, only the most basic peripherals, a keyboard and mouse, are supported.

A number of articles have been written on this topic. Most are outdated, and the few recent ones are missing key information.

Security Advisories / Bulletins 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 ressources

Royce Williams list is different, listed by vendors responses:
https://www.techsolvency.com/story-so-far/cve-2021-44228-log4j-log4shell/
TBD

How to calculate accurate entropy of the session ID

1. What is an entropy?

Claude Shannon says:

The entropy is a statistical parameter which measures in a certain sense, how much information is produced on the average for each letter of a text in the language. If the language is translated into binary digits (0 or 1) in the most efficient way, the entropy H is the average number of binary digits required per letter of the original language.

-- NIST Special Publication 800-63-1 - Appendix A: Estimating Password Entropy and Strength

2. Why you need to know the accurate entropy?

reference

https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands

cheatsheet

The netfilter hooks in the kernel and where they hook in the packet flow

The figure below calls out

The netfilter hooks
The order of table traversal

	wget http://stedolan.github.io/jq/download/linux64/jq
	aws ec2 describe-instances --filters "Name=tag:Name,Values=$NAME" \
	"Name=instance-state-name,Values=running" \
	\| jq -r \
	".Reservations[] \| .Instances[] \| .InstanceId" \

	aws ec2 describe-volumes --filters \
	"Name=status,Values=available" \
	\| jq -r ".Volumes[] \| .VolumeId" \

	# Count total EBS based storage in AWS
	aws ec2 describe-volumes \| jq "[.Volumes[].Size] \| add"
	# Count total EBS storage with a tag filter
	aws ec2 describe-volumes --filters "Name=tag:Name,Values=CloudEndure Volume qjenc" \| jq "[.Volumes[].Size] \| add"
	# Describe instances concisely
	aws ec2 describe-instances \| jq '[.Reservations \| .[] \| .Instances \| .[] \| {InstanceId: .InstanceId, State: .State, SubnetId: .SubnetId, VpcId: .VpcId, Name: (.Tags[]\|select(.Key=="Name")\|.Value)}]'
	# Wait until $instance_id is running and then immediately stop it again
	aws ec2 wait instance-running --instance-id $instance_id && aws ec2 stop-instances --instance-id $instance_id

	# Get 10th instance in the account

	# ---------------------------------------------------------------------------
	#
	# Description: This file holds all my BASH configurations and aliases.
	# Much of this was originally copied from:
	# http://natelandau.com/my-mac-osx-bash_profile/
	#
	# Sections:
	# 1. Environment Configuration
	# 2. Make Terminal Better (remapping defaults and adding functionality)
	# 3. File and Folder Management

	#!/bin/bash

	# Global variable declarations
	format="plain"
	directories=()
	current_directory=`pwd`
	report_directory="${current_directory}/report/"
	fresh_report_directory="0"

	# usage