ESPILON-CTF-2026-Writeups/IoT/Nurse_Call
Eun0us 6a0877384d [+] Writeups v2 — sync solves, real points, scoreboard stats, cleanup
- Remove undeployed challenges: Phantom_Byte, Cr4cK_w1f1, Lain_Br34kC0r3 V1,
  Lain_VS_Knights, Lets_All_Love_UART, AETHER_NET, Last_Train_451, Web3/
- Sync 24 solve/ files from main CTF-Espilon repo
- Update all READMEs with real CTFd final scores at freeze
- Add git-header.png banner
- Rewrite README: scoreboard top 10, edition stats (1410 users, 264 boards,
  1344 solves), correct freeze date March 26 2026
2026-03-27 21:27:45 +01:00
..
solve [+] Writeups v2 — sync solves, real points, scoreboard stats, cleanup 2026-03-27 21:27:45 +01:00
README.md [+] Writeups v2 — sync solves, real points, scoreboard stats, cleanup 2026-03-27 21:27:45 +01:00

Nurse Call

Field Value
Category IoT
Difficulty Easy
Points 50
Author Eun0us
CTF Espilon 2026

Description

You gain access to the maintenance terminal of the patient call system at Clinique Sainte-Mika. The system reports phantom calls coming from a sealed room.

The previous technician did not finish his investigation. His session was left open.

Explore the logs, understand the anomaly, and find what hides in Room 013.

  • Terminal: tcp/<host>:1337

Format: ESPILON{flag}


TL;DR

Connect to the maintenance terminal. Read the logs to find phantom calls from Room 013 with payload 0x4c41494e. Decode the hex to ASCII to get LAIN. Run ./tools/reveil.sh --id LAIN to wake the module and receive the flag.


Tools

Tool Purpose
nc Terminal access
Hex-to-ASCII decoding Convert 0x4c41494e

Solution

Step 1 — Connect

nc <host> 1337

maintenance terminal with open session from the previous technician

Step 2 — Read the call log

cat logs/appels.log

The log shows repeated phantom calls from Room 013. The last line:

[ALERT] Room 013 — unknown payload: 0x4c41494e

appels.log showing the phantom call with hex payload

Step 3 — Decode the payload

bytes.fromhex("4c41494e").decode()  # 'LAIN'

Or: 0x4C = L, 0x41 = A, 0x49 = I, 0x4E = NLAIN

Step 4 — Confirm in the network log

cat logs/reseau.log

Contains: 0x4c41494e -> ASCII: "LAIN"

Step 5 — Read the maintenance log for the command syntax

cat logs/maintenance.log

The previous technician wrote: "Use reveil.sh --id with the payload ID."

Optionally:

cat config/navi-care.conf

Shows exact syntax: reveil.sh --id <MODULE_ID>

Step 6 — Wake the module

./tools/reveil.sh --id LAIN

reveil.sh printing the flag after receiving the LAIN module ID


Flag

ESPILON{r3v31ll3_m01_d4ns_l3_w1r3d}