Carrier: 2600 - SEC-T CTF 2026 Writeup
Description
The third number is transatlantic and the board behind it is closed too, and there is a room on it that answers to the sysop and to nobody else.
The sysop of a board running the same software it was unpacked from, on the same account it was unpacked with. That distribution is still out there.
The third board. Dial in through Carrier.
Solution
Details for the third board come from messages on Carrier: Chaos Static.
From this, we get the number 00-1-212-260 0300. The second message notes that
the board runs Impulse 7.1 with the default sysop account shipped in the
distribution.
Impulse 7.1 is open source: gitlab.serialport.org/bbs/impulse-7.1.
The default sysop credentials are in imp71rel/DATA/USER.LST as Sysop:FLARE.
This challenge’s modem uses 009 as the international prefix instead of 00,
so we dial ATDT00912122600300 from the modem connection.
After logging in as sysop, the first message holds the flag.
Flag: SECT{2600_hertz_and_the_whole_world_was_listening}