Incezt Net May 2026

The challenge description gave a single line:

nc challenge.ctf.com 31137

So the service runs on a TCP socket. The first thing is to just connect and see what it says.

$ nc challenge.ctf.com 31137
Welcome to Incezt Net!
> 

A tiny interactive prompt appears. Typing help shows the available commands: incezt net

> help
Commands:
  info          – display some information
  echo <msg>    – echo back your message
  calc <expr>   – evaluate a simple arithmetic expression
  quit          – exit

At first glance it looks like a benign calculator/echo service, but the presence of a calc command that evaluates an expression hints at possible code‑execution bugs (e.g., integer overflow, format string, or even a full blown expression parser).

We need to write system_addr (64‑bit) into 0x601040. Because %n writes the number of bytes printed so far, we’ll split the 8‑byte write into two 4‑byte halves (lower and upper) using two %n writes. The challenge description gave a single line: nc

The payload format:

[payload address 0x601040] [payload address 0x601048] <padding> %<low>c %8$hn %<high>c %9$hn

We need to compute the appropriate padding (<low> and <high>) so that the total number of printed characters equals the desired half‑values. So the service runs on a TCP socket

By dawn, the Incezt Net had woven itself through every streetlamp, every commuter rail, every flickering billboard. The city’s own rhythm changed:

People began to call it the Incezt Whisper, a subtle undercurrent that nudged them to look deeper, to feel the stories hidden beneath the glass and steel.

Incyte Corporation is a biopharmaceutical company focused on the discovery, development, and commercialization of novel medicines to treat serious diseases. The company is headquartered in Wilmington, Delaware.