A collection of awesome lists, manuals, blogs, hacks, one-liners and tools for Awesome Ninja Admins.
***
## Who is Ninja Admins?
- race of pure evil who rule the network through a monarchist feudal system
- they never opened the door for strangers (or anyone at all)
- they know very nasty piece of code like a **[fork bombs](https://en.wikipedia.org/wiki/Fork_bomb)**
- they can make dd is not a **[destroyer of disks](http://www.noah.org/wiki/Dd_-_Destroyer_of_Disks)**
- they know that `#!/usr/bin/env bash` superior to `#!/bin/bash`
- they know that `su -` logs in completely as root
- they miss and cry for **[Slackware](http://www.slackware.com/)** on production
- they love the old admin nix-world
## :ballot_box_with_check: Todo
- [ ] Add useful shell functions
- [ ] Add one-liners for collection tools (eg. CLI Tools)
- [ ] Add Ninja Admins T-Shirt stickers
- [ ] Generate Awesome Ninja Admins book (eg. pdf format)
## Ninja Admins Collection
#### CLI Tools
##### :black_small_square: Shells
:small_orange_diamond: Oh My ZSH! - the best framework for managing your Zsh configuration.
:small_orange_diamond: bash-it - framework for using, developing and maintaining shell scripts and custom commands for your daily work.
:small_orange_diamond: Oh My Fish - the Fishshell framework.
##### :black_small_square: Managers
: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.
##### :black_small_square: Network
: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: nmap - free and open source (license) utility for network discovery and security auditing.
:small_orange_diamond: hping - command-line oriented TCP/IP packet assembler/analyzer.
:small_orange_diamond: masscan - the fastest Internet port scanner, spews SYN packets asynchronously.
: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: tshark - dump and analyze network traffic (wireshark cli).
:small_orange_diamond: fierce - a DNS reconnaissance tool for locating non-contiguous IP space.
:small_orange_diamond: sublist3r - fast subdomains enumeration tool for penetration testers.
##### :black_small_square: SSL
:small_orange_diamond: sslyze
- fast and powerful SSL/TLS server scanning library.
:small_orange_diamond: sslscan - tests SSL/TLS enabled services to discover supported cipher suites.
:small_orange_diamond: testssl.sh - testing TLS/SSL encryption anywhere on any port.
##### :black_small_square: Auditing Tools
:small_orange_diamond: lynis - battle-tested security tool for systems running Linux, macOS, or Unix-based operating system.
##### :black_small_square: System Diagnostics/Debuggers
:small_orange_diamond: strace - diagnostic, debugging and instructional userspace utility for Linux.
:small_orange_diamond: sysdig - system exploration and troubleshooting tool with first class support for containers.
:small_orange_diamond: lsof - displays in its output information about files that are opened by processes.
:small_orange_diamond: FlameGraph - stack trace visualizer.
:small_orange_diamond: lsofgraph - small utility to convert Unix lsof output to a graph showing FIFO and UNIX interprocess communication.
##### :black_small_square: Log Analyzers
:small_orange_diamond: GoAccess - real-time web log analyzer and interactive viewer that runs in a terminal.
##### :black_small_square: Databases
:small_orange_diamond: usql - universal command-line interface for SQL databases.
:small_orange_diamond: pgcli - postgres CLI with autocompletion and syntax highlighting.
:small_orange_diamond: mycli - terminal client for MySQL with autocompletion and syntax highlighting.
#### Web Tools
##### :black_small_square: SSL
: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: urlscan.io - service to scan and analyse websites.
: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: cipherli.st - strong ciphers for Apache, Nginx, Lighttpd and more.
:small_orange_diamond: badssl.com - memorable site for testing clients against bad SSL configs.
:small_orange_diamond: tlsfun.de - registered for various tests regarding the TLS/SSL protocol.
: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.
##### :black_small_square: HTTP Headers
: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: Enable CORS - enable cross-origin resource sharing.
##### :black_small_square: DNS
:small_orange_diamond: ViewDNS - one source for free DNS related tools and information.
:small_orange_diamond: DNSlytics - online investigation tool.
:small_orange_diamond: DNS Spy - monitor, validate and verify your DNS configurations.
##### :black_small_square: Mail
:small_orange_diamond: MX Toolbox - all of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.
:small_orange_diamond: blacklistalert - checks to see if your domain is on a Real Time Spam Blacklist.
:small_orange_diamond: MultiRBL - complete IP check for sending Mailservers.
##### :black_small_square: Mass scanners (search engines)
: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).
##### :black_small_square: Net-tools
:small_orange_diamond: Netcraft - detailed report about the site, helping you to make informed choices about their integrity.
:small_orange_diamond: RIPE NCC - not-for-profit membership association, a Regional Internet Registry and the secretariat for the RIPE.
: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: RegExr - online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
:small_orange_diamond: Hardenize - deploy the security standards.
##### :black_small_square: Code parsers/playgrounds
:small_orange_diamond: ShellCheck - finds bugs in your shell scripts.
:small_orange_diamond: jsbin - live pastebin for HTML, CSS & JavaScript and more.
##### :black_small_square: Performance
: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.
##### :black_small_square: Passwords
: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.
#### Manuals/Howtos/Tutorials
##### :black_small_square: Bash
: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.
##### :black_small_square: Unix tutorials
:small_orange_diamond: nixCraft - linux and unix tutorials for new and seasoned sysadmin.
:small_orange_diamond: TecMint - the ideal Linux blog for Sysadmins & Geeks.
##### :black_small_square: Security
:small_orange_diamond: OWASP - worldwide not-for-profit charitable organization focused on improving the security of software.
:small_orange_diamond: Hacking Articles - LRaj Chandel's Security & Hacking Blog.
:small_orange_diamond: GTFOBins - list of Unix binaries that can be exploited by an attacker to bypass local security restrictions.
:small_orange_diamond: AWS security tools - make your AWS cloud environment more secure.
##### :black_small_square: Web Apps
:small_orange_diamond: Mozilla Web Security - help operational teams with creating secure web applications.
##### :black_small_square: Secret Knowledge
:small_orange_diamond: CTF Series : Vulnerable Machines - the steps below could be followed to find vulnerabilities and exploits.
:small_orange_diamond: How to start RE/malware analysis? - collection of some hints and useful links for the beginners.
:small_orange_diamond: LZone Cheat Sheets - all cheat sheets.
:small_orange_diamond: Dan’s Cheat Sheets’s - massive cheat sheets documentation.
:small_orange_diamond: The C10K problem - it's time for web servers to handle ten thousand clients simultaneously, don't you think?
#### Blogs
: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: Linux Audit - the Linux security blog about Auditing, Hardening and Compliance by Michael Boelen.
:small_orange_diamond:
Linux Security Expert - trainings, howtos, checklists, security tools and more.
:small_orange_diamond: The Grymoire - collection of useful incantations for wizards, be you computer wizards, magicians, or whatever.
#### Systems/Services
##### :black_small_square: Systems
:small_orange_diamond: Slackware - the most "Unix-like" Linux distribution.
: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.
##### :black_small_square: HTTP(s) Services
:small_orange_diamond: Varnish HTTP Cache - HTTP accelerator designed for content-heavy dynamic web sites.
##### :black_small_square: Security/hardening
:small_orange_diamond: Emerald Onion - seattle-based encrypted-transit internet service provider.
:small_orange_diamond: Unbound - validating, recursive, and caching DNS resolver (with TLS).
:small_orange_diamond: Knot Resolver - caching full resolver implementation, including both a resolver library and a daemon.
#### Awesome Lists
: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: Awesome Hacking Resources - collection of hacking/penetration testing resources to make you better.
:small_orange_diamond: Movies for Hackers - list of movies every hacker & cyberpunk must watch.
:small_orange_diamond: Awesome Pentest - collection of awesome penetration testing resources, tools and other shiny things.
:small_orange_diamond: Awesome Pcaptools - collection of tools developed by other researchers to process network traces.
:small_orange_diamond: Command-line-text-processing - from finding text to search and replace, from sorting to beautifying text and more.
:small_orange_diamond: Awesome Scalability - best practices in building High Scalability, High Availability, High Stability and more.
:small_orange_diamond: Awesome Postgres - list of awesome PostgreSQL software, libraries, tools and resources.
:small_orange_diamond: Free Security eBooks - list of a Free Security and Hacking eBooks.
#### Hacking/Penetration testing
##### :black_small_square: Bounty programs
: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.
##### :black_small_square: Web Training Apps (local installation)
:small_orange_diamond: Metasploitable 2 - vulnerable web application amongst security researchers.
: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.
##### :black_small_square: Labs
:small_orange_diamond: Hack The Box - online platform allowing you to test your penetration testing skills.
:small_orange_diamond: Hacking-Lab - online ethical hacking, computer network and security challenge platform.
:small_orange_diamond: pwnable.kr - non-commercial wargame site which provides various pwn challenges regarding system exploitation.
#### One-liners
##### Table of Contents
- **[System](#system)**
* [terminal](#tool-terminal)
* [mount](#tool-mount)
* [fuser](#tool-fuser)
* [ps](#tool-ps)
* [top](#tool-top)
* [strace](#tool-strace)
* [kill](#tool-kill)
* [find](#tool-find)
* [diff](#tool-diff)
* [tail](#tool-tail)
* [cpulimit](#tool-cpulimit)
* [pwdx](#tool-pwdx)
* [tr](#tool-tr)
* [chmod](#tool-chmod)
* [who](#tool-who)
* [screen](#tool-screen)
* [du](#tool-du)
* [inotifywait](#tool-inotifywait)
* [openssl](#tool-openssl)
* [gnutls-cli](#tool-gnutls-cli)
* [secure-delete](#tool-secure-delete)
* [dd](#tool-dd)
- **[HTTP/HTTPS](#http-https)**
* [curl](#tool-curl)
* [httpie](#tool-httpie)
- **[Network](#network)**
* [ssh](#tool-ssh)
* [linux-dev](#tool-linux-dev)
* [tcpdump](#tool-tcpdump)
* [tcpick](#tool-tcpick)
* [ngrep](#tool-ngrep)
* [hping3](#tool-hping3)
* [netcat](#tool-netcat)
* [socat](#tool-socat)
* [lsof](#tool-lsof)
* [netstat](#tool-netstat)
* [rsync](#tool-rsync)
* [host](#tool-host)
* [dig](#tool-dig)
* [network-other](#tool-network-other)
- **[Programming](#programming)**
* [awk](#tool-awk)
* [sed](#tool-sed)
* [grep](#tool-grep)
System
##### Tool: [terminal](https://en.wikipedia.org/wiki/Linux_console)
###### Reload shell without exit
```bash
exec $SHELL -l
```
###### Close shell keeping all subprocess running
```bash
disown -a && exit
```
###### Exit without saving shell history
```bash
kill -9 $$
unset HISTFILE && exit
```
###### Perform a branching conditional
```bash
true && { echo success;} || { echo failed; }
```
###### Pipe stdout and stderr to separate commands
```bash
some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)
```
###### Redirect stdout and stderr each to separate files and print both to the screen
```bash
(some_command 2>&1 1>&3 | tee errorlog ) 3>&1 1>&2 | tee stdoutlog
```
###### List of commands you use most often
```bash
history | \
awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | \
grep -v "./" | \
column -c3 -s " " -t | \
sort -nr | nl | head -n 20
```
###### Quickly backup a file
```bash
cp filename{,.orig}
```
###### Empty a file (truncate to 0 size)
```bash
>filename
```
###### Delete all files in a folder that don't match a certain file extension
```bash
rm !(*.foo|*.bar|*.baz)
```
###### Pass multi-line string to a file
```bash
# cat >filename ... - overwrite file
# cat >>filename ... - append to file
cat > filename << __EOF__
data data data
__EOF__
```
###### Edit a file on a remote host using vim
```bash
vim scp://user@host//etc/fstab
```
###### Create a directory and change into it at the same time
```bash
mkd () { mkdir -p "$@" && cd "$@"; }
```
###### Convert uppercase files to lowercase files
```bash
rename 'y/A-Z/a-z/' *
```
###### Print a row of characters across the terminal
```bash
printf "%`tput cols`s" | tr ' ' '#'
```
###### Show shell history without line numbers
```bash
history | cut -c 8-
fc -l -n 1 | sed 's/^\s*//'
```
###### Run command(s) after exit session
```bash
cat > /etc/profile << __EOF__
_after_logout() {
username=$(whoami)
for _pid in $(ps afx | grep sshd | grep "$username" | awk '{print $1}') ; do
kill -9 $_pid
done
}
trap _after_logout EXIT
__EOF__
```
###### Generate a sequence of numbers
```bash
for ((i=1; i<=10; i+=2)) ; do echo $i ; done
# alternative: seq 1 2 10
for ((i=5; i<=10; ++i)) ; do printf '%02d\n' $i ; done
# alternative: seq -w 5 10
```
___
##### Tool: [mount](https://en.wikipedia.org/wiki/Mount_(Unix))
###### Mount a temporary ram partition
```bash
mount -t tmpfs tmpfs /mnt -o size=64M
```
* `-t` - filesystem type
* `-o` - mount options
###### Remount a filesystem as read/write
```bash
mount -o remount,rw /
```
___
##### Tool: [fuser](https://en.wikipedia.org/wiki/Fuser_(Unix))
###### Kills a process that is locking a file
```bash
fuser -k filename
```
###### Show what PID is listening on specific port
```bash
fuser -v 53/udp
```
___
##### Tool: [ps](https://en.wikipedia.org/wiki/Ps_(Unix))
###### Show a 4-way scrollable process tree with full details
```bash
ps awwfux | less -S
```
###### Processes per user counter
```bash
ps hax -o user | sort | uniq -c | sort -r
```
___
##### Tool: [find](https://en.wikipedia.org/wiki/Find_(Unix))
###### Find files that have been modified on your system in the past 60 minutes
```bash
find / -mmin 60 -type f
```
###### Find all files larger than 20M
```bash
find / -type f -size +20M
```
###### Find duplicate files (based on MD5 hash)
```bash
find -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate -w 33
```
###### Change permission only for files
```bash
cd /var/www/site && find . -type f -exec chmod 766 {} \;
cd /var/www/site && find . -type f -exec chmod 664 {} +
```
###### Change permission only for directories
```bash
cd /var/www/site && find . -type d -exec chmod g+x {} \;
cd /var/www/site && find . -type d -exec chmod g+rwx {} +
```
###### Find files and directories for specific user
```bash
find . -user -print
```
###### Find files and directories for all without specific user
```bash
find . \!-user -print
```
###### Delete older files than 60 days
```bash
find . -type f -mtime +60 -delete
```
###### Recursively remove all empty sub-directories from a directory
```bash
find . -depth -type d -empty -exec rmdir {} \;
```
###### How to find all hard links to a file
```bash
find -xdev -samefile filename
```
___
##### Tool: [top](https://en.wikipedia.org/wiki/Top_(software))
###### Use top to monitor only all processes with the specific string
```bash
top -p $(pgrep -d , )
```
* `` - process containing str (eg. nginx, worker)
___
##### Tool: [strace](https://en.wikipedia.org/wiki/Strace)
###### Track the open request of a network port
```bash
strace -f -e trace=bind nc -l 80
```
###### Track the open request of a network port (show TCP/UDP)
```bash
strace -f -e trace=network nc -lu 80
```
___
##### Tool: [kill](https://en.wikipedia.org/wiki/Kill_(command))
###### Kill a process running on port
```bash
kill -9 $(lsof -i : | awk '{l=$2} END {print l}')
```
___
##### Tool: [diff](https://en.wikipedia.org/wiki/Diff)
###### Compare two directory trees
```bash
diff <(cd directory1 && find | sort) <(cd directory2 && find | sort)
```
___
##### Tool: [tail](https://en.wikipedia.org/wiki/Tail_(Unix))
###### Annotate tail -f with timestamps
```bash
tail -f file | while read ; do echo "$(date +%T.%N) $REPLY" ; done
```
###### Analyse an Apache access log for the most common IP addresses
```bash
tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail
```
###### Analyse web server log and show only 5xx http codes
```bash
tail -n 100 -f /path/to/logfile | grep "HTTP/[1-2].[0-1]\" [5]"
```
___
##### Tool: [tar](https://en.wikipedia.org/wiki/Tar_(computing))
###### System backup with exclude specific directories
```bash
cd /
tar -czvpf /mnt/system$(date +%d%m%Y%s).tgz --directory=/ \
--exclude=proc/* --exclude=sys/* --exclude=dev/* --exclude=mnt/* .
```
###### System backup with exclude specific directories (pigz)
```bash
cd /
tar cvpf /backup/snapshot-$(date +%d%m%Y%s).tgz --directory=/ \
--exclude=proc/* --exclude=sys/* --exclude=dev/* \
--exclude=mnt/* --exclude=tmp/* --use-compress-program=pigz .
```
___
##### Tool: [dump](https://en.wikipedia.org/wiki/Dump_(program))
###### System backup to file
```bash
dump -y -u -f /backup/system$(date +%d%m%Y%s).lzo /
```
###### Restore system from lzo file
```bash
cd /
restore -rf /backup/system$(date +%d%m%Y%s).lzo
```
___
##### Tool: [cpulimit](http://cpulimit.sourceforge.net/)
###### Limit the cpu usage of a process
```bash
cpulimit -p pid -l 50
```
___
##### Tool: [pwdx](https://www.cyberciti.biz/faq/unix-linux-pwdx-command-examples-usage-syntax/)
###### Show current working directory of a process
```bash
pwdx
```
___
##### Tool: [taskset](https://www.cyberciti.biz/faq/taskset-cpu-affinity-command/)
###### Start a command on only one CPU core
```bash
taskset -c 0
```
___
##### Tool: [tr](https://en.wikipedia.org/wiki/Tr_(Unix))
###### Show directories in the PATH, one per line
```bash
tr : '\n' <<<$PATH
```
___
##### Tool: [chmod](https://en.wikipedia.org/wiki/Chmod)
###### Remove executable bit from all files in the current directory
```bash
chmod -R -x+X *
```
###### Restore permission for /bin/chmod
```bash
# 1:
cp /bin/ls chmod.01
cp /bin/chmod chmod.01
./chmod.01 700 file
# 2:
/bin/busybox chmod 0700 /bin/chmod
# 3:
setfacl --set u::rwx,g::---,o::--- /bin/chmod
```
___
##### Tool: [who](https://en.wikipedia.org/wiki/Who_(Unix))
###### Find last reboot time
```bash
who -b
```
___
##### Tool: [screen](https://en.wikipedia.org/wiki/GNU_Screen)
###### Start screen in detached mode
```bash
screen -d -m []
```
___
##### Tool: [du](https://en.wikipedia.org/wiki/GNU_Screen)
###### Show 20 biggest directories with 'K M G'
```bash
du | \
sort -r -n | \
awk '{split("K M G",v); s=1; while($1>1024){$1/=1024; s++} print int($1)" "v[s]"\t"$2}' | \
head -n 20
```
___
##### Tool: [inotifywait](https://en.wikipedia.org/wiki/GNU_Screen)
###### Init tool everytime a file in a directory is modified
```bash
while true ; do inotifywait -r -e MODIFY dir/ && ls dir/ ; done;
```
___
##### Tool: [openssl](https://www.openssl.org/)
###### Testing connection to remote host
```bash
echo | openssl s_client -connect google.com:443 -showcerts
```
###### Testing connection to remote host (with SNI support)
```bash
echo | openssl s_client -showcerts -servername google.com -connect google.com:443
```
###### Testing connection to remote host with specific ssl version
```bash
openssl s_client -tls1_2 -connect google.com:443
```
###### Testing connection to remote host with specific ssl cipher
```bash
openssl s_client -cipher 'AES128-SHA' -connect google.com:443
```
###### Generate private key
```bash
# _ciph: des3, aes
( _ciph="des3" ; _fd="private.key" ; _len="2048" ; \
openssl genrsa -${_ciph} -out ${_fd} ${_len} )
```
###### Remove password from private key
```bash
( _fd="private.key" ; _fd_unp="private_unp.key" ; \
openssl rsa -in ${_fd} -out ${_fd_unp} )
```
###### Get public key from private key
```bash
( _fd="private.key" ; _fd_pub="public.key" ; \
openssl rsa -pubout -in ${_fd} -out ${_fd_pub} )
```
###### Generate private key + csr
```bash
( _fd="private.key" ; _fd_csr="request.csr" ; _len="2048" ; \
openssl req -out ${_fd_csr} -new -newkey rsa:${_len} -nodes -keyout ${_fd} )
```
###### Generate csr
```bash
( _fd="private.key" ; _fd_csr="request.csr" ; \
openssl req -out ${_fd_csr} -new -key ${_fd} )
```
###### Generate csr (metadata from exist certificate)
```bash
( _fd="private.key" ; _fd_csr="request.csr" ; _fd_crt="cert.crt" ; \
openssl x509 -x509toreq -in ${_fd_crt} -out ${_fd_csr} -signkey ${_fd} )
```
###### Generate csr with -config param
```bash
( _fd="private.key" ; _fd_csr="request.csr" ; \
openssl req -new -sha256 -key ${_fd} -out ${_fd_csr} \
-config <(
cat <<-EOF
[req]
default_bits = 2048
prompt = no
default_md = sha256
req_extensions = req_ext
distinguished_name = dn
[ dn ]
C=
ST=
L=
O=
OU=
CN=
[ req_ext ]
subjectAltName = @alt_names
[ alt_names ]
DNS.1 =
DNS.2 =
DNS.3 =
EOF
))
```
###### Convert DER to PEM
```bash
( _fd_der="cert.crt" ; _fd_pem="cert.pem" ; \
openssl x509 -in ${_fd_der} -inform der -outform pem -out ${_fd_pem} )
```
###### Convert PEM to DER
```bash
( _fd_der="cert.crt" ; _fd_pem="cert.pem" ; \
openssl x509 -in ${_fd_pem} -outform der -out ${_fd_der} )
```
###### Checking whether the private key and the certificate match
```bash
(openssl rsa -noout -modulus -in private.key | openssl md5 ; openssl x509 -noout -modulus -in certificate.crt | openssl md5) | uniq
```
___
##### Tool: [gnutls-cli](https://gnutls.org/manual/html_node/gnutls_002dcli-Invocation.html)
###### Testing connection to remote host (with sni)
```bash
gnutls-cli -p 443 google.com
```
###### Testing connection to remote host (without sni)
```bash
gnutls-cli --disable-sni -p 443 google.com
```
___
##### Tool: [secure-delete](https://wiki.archlinux.org/index.php/Securely_wipe_disk)
###### Secure delete with shred
```bash
shred -vfuz -n 10 file
shred --verbose --random-source=/dev/urandom -n 1 /dev/sda
```
###### Secure delete with scrub
```bash
scrub -p dod /dev/sda
scrub -p dod -r file
```
###### Secure delete with badblocks
```bash
badblocks -s -w -t random -v /dev/sda
badblocks -c 10240 -s -w -t random -v /dev/sda
```
###### Secure delete with secure-delete
```bash
srm -vz /tmp/file
sfill -vz /local
sdmem -v
swapoff /dev/sda5 && sswap -vz /dev/sda5
```
___
##### Tool: [dd](https://en.wikipedia.org/wiki/Dd_(Unix))
###### Show dd status every so often
```bash
dd status=progress
watch --interval 5 killall -USR1 dd
```
###### Redirect output to a file with dd
```bash
echo "string" | dd of=filename
```
HTTP/HTTPS
##### Tool: [curl](https://curl.haxx.se)
```bash
curl -Iks https://www.google.com
```
* `-I` - show response headers only
* `-k` - insecure connection when using ssl
* `-s` - silent mode (not display body)
```bash
curl -Iks --location -X GET -A "x-agent" https://www.google.com
```
* `--location` - follow redirects
* `-X` - set method
* `-A` - set user-agent
```bash
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
###### Check DNS and HTTP trace with headers for specific domains
```bash
### Set domains and external dns servers.
_domain_list=(google.com) ; _dns_list=("8.8.8.8" "1.1.1.1")
for _domain in "${_domain_list[@]}" ; do
printf '=%.0s' {1..48}
echo
printf "[\\e[1;32m+\\e[m] resolve: %s\\n" "$_domain"
for _dns in "${_dns_list[@]}" ; do
# Resolve domain.
host "${_domain}" "${_dns}"
echo
done
for _proto in http https ; do
printf "[\\e[1;32m+\\e[m] trace + headers: %s://%s\\n" "$_proto" "$_domain"
# Get trace and http headers.
curl -Iks -A "x-agent" --location "${_proto}://${_domain}"
echo
done
done
unset _domain_list _dns_list
```
___
##### Tool: [httpie](https://httpie.org/)
```bash
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
```bash
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
```bash
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
##### Tool: [ssh](https://www.openssh.com/)
###### Compare a remote file with a local file
```bash
ssh user@host cat /path/to/remotefile | diff /path/to/localfile -
```
###### SSH connection through host in the middle
```bash
ssh -t reachable_host ssh unreachable_host
```
###### Run command over ssh on remote host
```bash
cat > cmd.txt << __EOF__
cat /etc/hosts
__EOF__
ssh host -l user $(&1 | tee -a "${_sesdir}/$(date +%Y%m%d).log"
}
# Alias:
alias ssh='_ssh_sesslog'
```
###### Using Keychain for SSH logins
```bash
### Delete all of ssh-agent's keys.
function _scl() {
/usr/bin/keychain --clear
}
### Add key to keychain.
function _scg() {
/usr/bin/keychain /path/to/private-key
source "$HOME/.keychain/$HOSTNAME-sh"
}
```
___
##### Tool: [linux-dev](https://www.tldp.org/LDP/abs/html/devref1.html)
###### Testing remote connection to port
```bash
timeout 1 bash -c "//" >/dev/null 2>&1 ; echo $?
```
* `` - set remote host
* `` - set destination port
###### Read and write to TCP or UDP sockets with common bash tools
```bash
exec 5<>/dev/tcp//; cat <&5 & cat >&5; exec 5>&-
```
___
##### Tool: [tcpdump](http://www.tcpdump.org/)
```bash
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|any]` - 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]`
```bash
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
___
##### Tool: [tcpick](http://tcpick.sourceforge.net/)
###### Analyse packets in real-time
```bash
while true ; do tcpick -a -C -r dump.pcap ; sleep 2 ; clear ; done
```
___
##### Tool: [ngrep](http://ngrep.sourceforge.net/usage.html)
```bash
ngrep -d eth0 "www.google.com" port 443
```
* `-d [iface|any]` - set interface
* `[domain]` - set hostname
* `port [1-65535]` - set port number
```bash
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
```bash
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
```bash
ngrep -d eth0 -qt 'HTTP' 'tcp'
```
* `HTTP` - show http headers
* `tcp|udp` - set protocol
* `[src|dst] host [ip|hostname]` - set direction for specific node
```bash
ngrep -l -q -d eth0 -i "User-Agent: curl*"
```
* `-l` - stdout line buffered
* `-i` - case-insensitive search
___
##### Tool: [hping3](http://www.hping.org/)
```bash
hping3 -V -p 80 -s 5050 www.google.com
```
* `-V|--verbose` - verbose mode
* `-p|--destport` - set destination port
* `-s|--baseport` - set source port
* `` - 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
```bash
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)
```bash
hping3 -V -c 1000000 -d 120 -S -w 64 -p 80 --flood --rand-source
```
* `--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)
___
##### Tool: [netcat](http://netcat.sourceforge.net/)
```bash
nc -kl 5000
```
* `-l` - listen for an incoming connection
* `-k` - listening after client has disconnected
* `>filename.out` - save receive data to file (optional)
```bash
nc 192.168.0.1 5051 < filename.in
```
* `< filename.in` - send data to remote host
```bash
nc -vz 10.240.30.3 5000
```
* `-v` - verbose output
* `-z` - scan for listening daemons
```bash
nc -vzu 10.240.30.3 1-65535
```
* `-u` - scan only udp ports
###### Transfer data file (archive)
```bash
server> nc -l 5000 | tar xzvfp -
client> tar czvfp - /path/to/dir | nc 10.240.30.3 5000
```
###### Launch remote shell
```bash
server> nc -l 5000 -e /bin/bash
client> nc 10.240.30.3 5000
```
###### Simple file server
```bash
while true ; do nc -l 5000 | tar -xvf - ; done
```
###### Simple minimal HTTP Server
```bash
while true ; do nc -l -p 1500 -c 'echo -e "HTTP/1.1 200 OK\n\n $(date)"' ; done
```
###### Simple HTTP Server
> Restarts web server after each request - remove `while` condition for only single connection.
```bash
cat > index.html << __EOF__
Hello! It's a site.