5.0 KiB
5.0 KiB
CTF Espilon — Write-ups
Welcome to the official write-up repository for CTF Espilon, a themed CTF inspired by the Serial Experiments Lain universe, set inside the WIRED-MED hospital network of Clinique Sainte-Mika and the surrounding Lain lore.
Challenge Index
| # | File | Category | Difficulty | Points | Flag |
|---|---|---|---|---|---|
| 1 | ESP_Start | ESP | Easy | 50 | ESPILON{st4rt_th3_w1r3} |
| 2 | Jnouned_Router | ESP | Multi (Easy→Hard) | 100/200/300/400 | 4 flags |
| 3 | Phantom_Byte | ESP | Multi (Easy→Hard) | 100/200/300/500 | 4 flags |
| 4 | CAN_Bus_Implant | Hardware | Medium-Hard | 500 | ESPILON{c4n_bus_1mpl4nt_4ct1v3} |
| 5 | Glitch_The_Wired | Hardware | Medium-Hard | 500 | ESPILON{gl1tch_byp4ss_s3cur3_b00t} |
| 6 | NAVI_I2C_Sniff | Hardware | Medium-Hard | 500 | ESPILON{n4v1_12c_bus_mast3r} |
| 7 | Phantom_JTAG | Hardware | Medium-Hard | 500 | ESPILON{jt4g_d3bug_unl0ck3d} |
| 8 | Serial_Experimental_00 | Hardware | Easy | 150 | ESPILON{l41n_s3r14l_3xp_00} |
| 9 | Signal_Tap_Lain | Hardware | Medium-Hard | 500 | ESPILON{s1gn4l_t4p_d3c0d3d} |
| 10 | Wired_SPI_Exfil | Hardware | Medium-Hard | 500 | ESPILON{sp1_fl4sh_3xf1ltr4t3d} |
| 11 | The_Wired | Intro | Medium | 400 | ESPILON{th3_w1r3d_kn0ws_wh0_y0u_4r3} |
| 12 | Anesthesia_Gateway | IoT | Medium-Hard | 500 | ESPILON{mQtt_g4tw4y_4n3sth3s14} |
| 13 | Cr4cK_W1F1 | IoT | Medium | — | CTF{CR4CK_W1F1_EXAMPLE} |
| 14 | Lain_Br34kC0r3 | IoT | Medium | 500 | ECW{LAIN_Br34k_CryPT0} |
| 15 | Lain_Br34kC0r3_V2 | IoT | Hard | 500 | ESPILON{3sp32_fl4sh_dump_r3v3rs3d} |
| 16 | Lain_VS_Knights | IoT | Hard | — | ESPILON{0nlY_L41N_C4N_S0lv3} |
| 17 | Lets_All_Hate_UART | IoT | Medium-Hard | 500 | ESPILON{u4rt_nvs_fl4sh_d1sc0v3ry} |
| 18 | Lets_All_Love_UART | IoT | Easy | 500 | ESPILON{LAIN_TrUsT_U4RT} |
| 19 | Nurse_Call | IoT | Easy | 200 | ESPILON{r3v31ll3_m01_d4ns_l3_w1r3d} |
| 20 | Observe_The_Wired | IoT | Medium-Hard | — | ESPILON{c0ap_0bs3rv3_th3_w1r3d} |
| 21 | Wired_Airwave_013 | IoT | Medium | 500 | ESPILON{sdr_fsk_w1r3d_m3d_013} |
| 22 | Accela_Signal | Misc | Hard | 500 | ESPILON{4cc3l4_ch1rp_spr34d_w1r3d} |
| 23 | AETHER_NET | Misc | Insane | — | ESPILON{4eth3r_n3t_d3us_4dm1n} |
| 24 | Last_Train_451 | Misc | TBD | — | TBD |
| 25 | LAYER_ZERO | Misc | Hard | 600 | ESPILON{kn1ghts_0f_th3_w1r3d_pr0t0c0l7} |
| 26 | Patient_Portal | Misc | Medium-Hard | 500 | ESPILON{r00t_0f_s41nt3_m1k4} |
| 27 | Cyberia_Grid | OT | Medium-Hard | 500 | ESPILON{cyb3r14_ps7ch3_pr0c3ss0r} |
| 28 | Operating_Room | OT | Medium-Hard | 500 | ESPILON{m0dbu5_0p3r4t1ng_r00m} |
| 29 | Protocol_Seven | OT | Hard | 600 | ESPILON{pr0t0c0l_7_m3rg3_c0mpl3t3} |
| 30 | Schumann_Resonance | OT | Medium | 400 | ESPILON{sch0m4nn_r3s0n4nc3_783} |
| 31 | Tachibana_SCADA | OT | Medium-Hard | 500 | ESPILON{31r1_k1ds_pr0t0c0l_s3v3n} |
| 32 | GANTZ_BALL_CONTRACT | Web3 | Insane | 500 | ESPILON{g4ntz_b4ll_100_p01nts_fr33d0m} |
| 33 | TACHIBANA_FIRMWARE_REGISTRY | Web3 | Insane | 500 | ESPILON{t4ch1b4n4_fuzz_f1rmw4r3_r3g1stry} |
Categories
- ESP — ESP32 firmware challenges (flashing, UART, WiFi, custom protocols)
- Hardware — Simulated hardware bus interfaces (UART, I2C, SPI, JTAG, CAN, signal decoding, voltage glitching)
- Intro — Entry-point challenge covering the ESPILON bot C2 infrastructure
- IoT — IoT protocol challenges (MQTT, CoAP, UART, SDR/FSK, WiFi)
- Misc — Mixed challenges (signal processing, web exploitation, multi-pivot)
- OT — Operational Technology / Industrial protocols (Modbus, BACnet, OPC-UA, EtherNet/IP)
- Web3 — Ethereum smart contract exploitation (reentrancy, assembly underflow, bytecode reversal)
Lore
The CTF is set in the world of Serial Experiments Lain. Challenges revolve around the WIRED-MED medical network of Clinique Sainte-Mika, the covert KIDS experiment at Tachibana General Laboratories, and the mysterious Protocol Seven scattered across industrial systems by Eiri Masami before his disappearance. Knights of the Eastern Calculus guard the deepest layers.
Author: Eun0us — CTF Espilon 2026