• race of pure evil who rule the network through a monarchistic feudelic system
• they never opened the door for strangers (or anyone at all)
• they know very nasty piece of code like a fork bombs
• they can make dd is not a disk destroyer
• they know that #!/usr/bin/env bash superior to #!/bin/bash
• they know that su - logs in completely as root
• they love the old admin nix-world

  :small_orange_diamond: Oh My ZSH! - the best framework for managing your Zsh configuration.
  :small_orange_diamond: bash-it - a community Bash framework.

  :small_orange_diamond: Midnight Commander - visual file manager, licensed under GNU General Public License.
  :small_orange_diamond: screen - full-screen window manager that multiplexes a physical terminal.
  :small_orange_diamond: tmux - terminal multiplexer, lets you switch easily between several programs in one terminal.

  :small_orange_diamond: Curl - command line tool and library for transferring data with URLs.
  :small_orange_diamond: HTTPie - a user-friendly HTTP client.
  :small_orange_diamond: gnutls-cli - client program to set up a TLS connection to some other computer.
  :small_orange_diamond: netcat - networking utility which reads and writes data across network connections, using the TCP/IP protocol.
  :small_orange_diamond: tcpdump - powerful command-line packet analyzer.

  :small_orange_diamond: pgcli - postgres CLI with autocompletion and syntax highlighting.

  :small_orange_diamond: SSL Server Test - free online service performs a deep analysis of the configuration of any SSL web server.
  :small_orange_diamond: SSL Server Test (DEV) - free online service performs a deep analysis of the configuration of any SSL web server.
  :small_orange_diamond: ImmuniWeb® SSLScan - test SSL/TLS (PCI DSS, HIPAA and NIST).
  :small_orange_diamond: Report URI - monitoring security policies like CSP and HPKP.
  :small_orange_diamond: CSP Evaluator - allows developers and security experts to check if a Content Security Policy.
  :small_orange_diamond: Common CA Database - repository of information about CAs, and their root and intermediate certificates.
  :small_orange_diamond: CERTSTREAM - real-time certificate transparency log update stream.

  :small_orange_diamond: Security Headers - analyse the HTTP response headers (with rating system to the results).
  :small_orange_diamond: Observatory by Mozilla - set of tools to analyze your website.

  :small_orange_diamond: ViewDNS - one source for free DNS related tools and information.
  :small_orange_diamond: DNS Spy - monitor, validate and verify your DNS configurations.
  :small_orange_diamond: DNSlytics - online investigation tool.

  :small_orange_diamond: MX Toolbox - all of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.

  :small_orange_diamond: Censys - platform that helps information security practitioners discover, monitor, and analyze devices.
  :small_orange_diamond: Shodan - the world's first search engine for Internet-connected devices.
  :small_orange_diamond: GreyNoise - mass scanner (such as Shodan and Censys).
  :small_orange_diamond: Hardenize - deploy the security standards.

  :small_orange_diamond: Netcraft - detailed report about the site, helping you to make informed choices about their integrity.
  :small_orange_diamond: Security Trails - APIs for Security Companies, Researchers and Teams.
  :small_orange_diamond: Online Curl - curl test, analyze HTTP Response Headers.
  :small_orange_diamond: Ping.eu - online Ping, Traceroute, DNS lookup, WHOIS and others.
  :small_orange_diamond: Network-Tools - network tools for webmasters, IT technicians & geeks.
  :small_orange_diamond: URL Encode/Decode - tool from above to either encode or decode a string of text.

  :small_orange_diamond: GTmetrix - analyze your site’s speed and make it faster.
  :small_orange_diamond: Sucuri loadtimetester - test here the performance of any of your sites from across the globe.

  :small_orange_diamond: Random.org - generate random passwords.
  :small_orange_diamond: Gotcha? - list of 1.4 billion accounts circulates around the Internet.
  :small_orange_diamond: have i been pwned? - check if you have an account that has been compromised in a data breach.

  :small_orange_diamond: pure-bash-bible - a collection of pure bash alternatives to external processes.
  :small_orange_diamond: The Bash Hackers Wiki - hold documentation of any kind about GNU Bash.

  :small_orange_diamond: nixCraft - linux and unix tutorials for new and seasoned sysadmin.
  :small_orange_diamond: TecMint - the ideal Linux blog for Sysadmins & Geeks.

  :small_orange_diamond: Hacking Articles - LRaj Chandel's Security & Hacking Blog.

  :small_orange_diamond: Brendan Gregg's Blog - Brendan Gregg is an industry expert in computing performance and cloud computing.
  :small_orange_diamond: Gynvael "GynDream" Coldwind - Gynvael is a IT security engineer at Google.
  :small_orange_diamond: Michał "lcamtuf" Zalewski - "white hat" hacker, computer security expert.
  :small_orange_diamond: Mattias Geniar - developer, Sysadmin, Blogger, Podcaster and Public Speaker.
  :small_orange_diamond: Nick Craver - Software Developer and Systems Administrator for Stack Exchange.
  :small_orange_diamond: Robert Penz - IT security Expert.
  :small_orange_diamond: Scott Helme - Security Researcher, international speaker and founder of securityheaders.com and report-uri.com.
  :small_orange_diamond: Kacper Szurek - Detection Engineer at ESET.
  :small_orange_diamond: Troy Hunt - Microsoft Regional Director and Microsoft Most Valuable Professional for Developer Security.

  :small_orange_diamond: OpenBSD - multi-platform 4.4BSD-based UNIX-like operating system.
  :small_orange_diamond: HardenedBSD - HardenedBSD aims to implement innovative exploit mitigation and security solutions.

  :small_orange_diamond: Varnish HTTP Cache - HTTP accelerator designed for content-heavy dynamic web sites.

  :small_orange_diamond: Emerald Onion - Seattle-based encrypted-transit internet service provider.

  :small_orange_diamond: Awesome Sysadmin - amazingly awesome open source sysadmin resources.
  :small_orange_diamond: Awesome Shell - awesome command-line frameworks, toolkits, guides and gizmos.
  :small_orange_diamond: Awesome-Hacking - awesome lists for hackers, pentesters and security researchers.

  :small_orange_diamond: Openbugbounty - allows any security researcher reporting a vulnerability on any website.
  :small_orange_diamond: hackerone - global hacker community to surface the most relevant security issues.
  :small_orange_diamond: bugcrowd - crowdsourced cybersecurity for the enterprise.
  :small_orange_diamond: Crowdshield - crowdsourced Security & Bug Bounty Management.

  :small_orange_diamond: DVWA - PHP/MySQL web application that is damn vulnerable.
  :small_orange_diamond: OWASP Mutillidae II - free, open source, deliberately vulnerable web-application.
  :small_orange_diamond: OWASP Juice Shop Project - the most bug-free vulnerable application in existence.
  :small_orange_diamond: OWASP WebGoat Project - insecure web application maintained by OWASP designed to teach web app security.
  :small_orange_diamond: Security Ninjas - open source application security training program.

• System
  • terminal
  • mount
  • fuser
• HTTP/HTTPS
  • curl
  • httpie
• Network
  • openssh
  • linux-dev
  • tcpdump
  • ngrep
  • hping3
  • netcat
  • socat
  • lsof
  • netstat
• Programming
  • awk

System

disown -a && exit

kill -9 $$

history | awk '{ a[$2]++ } END { for(i in a) { print a[i] " " i } }' | sort -rn | head

cp filename{,.orig}

rm !(*.foo|*.bar|*.baz)

vim scp://user@host//etc/fstab

mount -t tmpfs tmpfs /mnt -o size=64M

• -t - filesystem type
• -o - mount options

fuser -k filename

HTTP/HTTPS

curl -Iks https://www.google.com

• -I - show response headers only
• -k - insecure connection when using ssl
• -s - silent mode (not display body)

curl -Iks --location -X GET -A "x-agent" https://www.google.com

• --location - follow redirects
• -X - set method
• -A - set user-agent

curl -Iks --location -X GET -A "x-agent" --proxy http://127.0.0.1:16379 https://www.google.com

• --proxy [socks5://|http://] - set proxy server

http -p Hh https://www.google.com

• -p - print request and response headers
  • H - request headers
  • B - request body
  • h - response headers
  • b - response body

http -p Hh --follow --max-redirects 5 --verify no https://www.google.com

• -F, --follow - follow redirects
• --max-redirects N - maximum for --follow
• --verify no - skip SSL verification

http -p Hh --follow --max-redirects 5 --verify no --proxy http:http://127.0.0.1:16379 https://www.google.com

• --proxy [http:] - set proxy server

Network

ssh user@host cat /path/to/remotefile | diff /path/to/localfile -

ssh -t reachable_host ssh unreachable_host

timeout 1 bash -c "</dev/tcp/<host>/<port>" >/dev/null 2>&1 ; echo $?

• <host> - set remote host
• <port> - set destination port

tcpdump -ne -i eth0 -Q in host 192.168.252.1 and port 443

• -n - don't convert addresses
• -e - print the link-level headers
• -i [iface] - set interface
• -Q|-D [in|out|inout] - choose send/receive direction (-D - for old tcpdump versions)
• host [ip|hostname] - set host, also [host not]
• [and|or] - set logic
• port [1-65535] - set port number, also [port not]

tcpdump -ne -i eth0 -Q in host 192.168.252.1 and port 443 -c 5 -w tcpdump.pcap

• -c [num] - capture only num number of packets
• -w [filename] - write packets to file, -r [filename] - reading from file

ngrep -d eth0 "www.google.com" port 443

• -d [iface|any] - set interface
• [domain] - set hostname
• port [1-65535] - set port number

ngrep -d eth0 "www.google.com" (host 10.240.20.2) and (port 443)

• (host [ip|hostname]) - filter by ip or hostname
• (port [1-65535]) - filter by port number

ngrep -d eth0 -qt -O ngrep.pcap "www.google.com" port 443

• -q - quiet mode (only payloads)
• -t - added timestamps
• -O [filename] - save output to file, -I [filename] - reading from file

ngrep -d eth0 -qt 'HTTP' 'tcp'

• HTTP - show http headers
• tcp|udp - set protocol
• [src|dst] host [ip|hostname] - set direction for specific node

hping3 -V -p 80 -s 5050 <scan_type> www.google.com

• -V|--verbose - verbose mode
• -p|--destport - set destination port
• -s|--baseport - set source port
• <scan_type> - set scan type
  • -F|--fin - set FIN flag, port open if no reply
  • -S|--syn - set SYN flag
  • -P|--push - set PUSH flag
  • -A|--ack - set ACK flag (use when ping is blocked, RST response back if the port is open)
  • -U|--urg - set URG flag
  • -Y|--ymas - set Y unused flag (0x80 - nullscan), port open if no reply
  • -M 0 -UPF - set TCP sequence number and scan type (URG+PUSH+FIN), port open if no reply

hping3 -V -c 1 -1 -C 8 www.google.com

• -c [num] - packet count
• -1 - set ICMP mode
• -C|--icmptype [icmp-num] - set icmp type (default icmp-echo = 8)

hping3 -V -c 1000000 -d 120 -S -w 64 -p 80 --flood --rand-source <remote_host>

• --flood - sent packets as fast as possible (don't show replies)
• --rand-source - random source address mode
• -d --data - data size
• -w|--win - winsize (default 64)

nc -kl 5000

• -l - listen for an incoming connection
• -k - listening after client has disconnected
• >filename.out - save receive data to file (optional)

nc 192.168.0.1 5051 < filename.in

• < filename.in - send data to remote host

nc -vz 10.240.30.3 5000

• -v - verbose output
• -z - scan for listening daemons

nc -vzu 10.240.30.3 1-65535

• -u - scan only udp ports

server> nc -l 5000 | tar xzvfp -
client> tar czvfp - /path/to/dir | nc 10.240.30.3 5000

server> nc -l 5000 -e /bin/bash
client> nc 10.240.30.3 5000

Restarts web server after each request - remove while condition for only single connection.

cat > index.html << __EOF__
<!doctype html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
        <title></title>
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
    </head>
    <body>

    <p>

      Hello! It's a site.

    </p>

    </body>
</html>
__EOF__

server> while : ; do \
(echo -ne "HTTP/1.1 200 OK\r\nContent-Length: $(wc -c <index.html)\r\n\r\n" ; cat index.html;) \
| nc -l -p 5000 \
; done

• -p - port number

#!/usr/bin/env bash

if [[ $# != 2 ]] ; then
  printf "%s\\n" \
         "usage: ./nc-proxy listen-port bk_host:bk_port"
fi

_listen_port="$1"
_bk_host=$(echo "$2" | cut -d ":" -f1)
_bk_port=$(echo "$2" | cut -d ":" -f2)

printf "  lport: %s\\nbk_host: %s\\nbk_port: %s\\n\\n" \
       "$_listen_port" "$_bk_host" "$_bk_port"

_tmp=$(mktemp -d)
_back="$_tmp/pipe.back"
_sent="$_tmp/pipe.sent"
_recv="$_tmp/pipe.recv"

trap 'rm -rf "$_tmp"' EXIT

mkfifo -m 0600 "$_back" "$_sent" "$_recv"

sed "s/^/=> /" <"$_sent" &
sed "s/^/<=  /" <"$_recv" &
nc -l -p "$_listen_port" <"$_back" \
  | tee "$_sent" \
  | nc "$_bk_host" "$_bk_port" \
  | tee "$_recv" >"$_back"

server> chmod +x nc-proxy && ./nc-proxy 8080 192.168.252.10:8000
  lport: 8080
bk_host: 192.168.252.10
bk_port: 8000

client> http -p h 10.240.30.3:8080
HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=31536000
Content-Length: 2748
Content-Type: text/html; charset=utf-8
Date: Sun, 01 Jul 2018 20:12:08 GMT
Last-Modified: Sun, 01 Apr 2018 21:53:37 GMT

socat - TCP4:10.240.30.3:22

• - - standard input (STDIO)
• TCP4:<params> - set tcp4 connection with specific params
  • [hostname|ip] - set hostname/ip
  • [1-65535] - set port number

socat TCP-LISTEN:1234,bind=127.0.0.1,reuseaddr,fork,su=nobody,range=127.0.0.0/8 UNIX-CLIENT:/tmp/foo

• TCP-LISTEN:<params> - set tcp listen with specific params
  • [1-65535] - set port number
  • bind=[hostname|ip] - set bind hostname/ip
  • reuseaddr -
  • fork -
  • su=nobody -
  • range=[ip-range] -
• UNIX-CLIENT:<params>
  • filename -

lsof -P -i -n

Tool: netstat

netstat -an | grep ESTABLISHED | awk '{print $5}' | awk -F: '{print $1}' | grep -v -e '^[[:space:]]*$' | sort | uniq -c | awk '{ printf("%s\t%s\t",$2,$1) ; for (i = 0; i < $1; i++) {printf("*")}; print "" }'

Programming

awk '!x[$0]++' filename