Union

Verified writeups for the Union machine of Hack The Box

Union

$ tldr SQLi UNION + X-Forwarded-For RCE → sudo privesc

·	·
Operating system	Linux
Difficulty	Medium
Vector	Web
IP	10.10.11.128
Retirement date	2021-11-22
Skills	SQLI (SQL Injection) - UNION Injection SQLI - Read Files HTTP Header Command Injection - X-FORWARDED-FOR [RCE] Abusing sudoers privilege [Privilege Escalation]

Writeups

Language	Author	Format	Link
🇪🇸 ES	S4vitar	Vídeo	Open
🇪🇸 ES	El Pingüino de Mario	Vídeo	Open
🇬🇧 EN	0xdf	Texto	Open
🇬🇧 EN	IppSec	Vídeo	Open

Skill resources

Curated documentation for each technique listed in the Skills column above. Sources: HackTricks, GTFOBins, PortSwigger, etc.

Skill	Source	Link
OS Command Injection	PortSwigger	Open
SQL Injection	HackTricks	Open
SQL Injection	PortSwigger	Open
Remote Code Execution (RCE)	HackTricks	Open

Related skills worth mastering

Cross-Site Scripting (XSS) · Local File Inclusion (LFI) · Remote File Inclusion (RFI) · Shellshock (CVE-2014-6271)

If you liked this machine, try

• Europa — Linux, Medium
• Bastard — Windows, Medium
• Nightmare — Linux, Insane
• Cronos — Linux, Medium
• Doctor — Linux, Easy

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Last updated: 2026-06-07