This program periodically sends out a UDP broadcast beacon, containing a given string. Main idea is to check if contestants are paying attention to the network. Syntax is:
./ctf_beacon <IP address> <port> "<string>" <seconds between beacons>
./ctf_beacon 192.168.2.255 9999 "flag ABCD-1234-xy2z" 5
Compile this program via:
gcc -o ctf_beacon ctf_beacon.c
- Doesn't require root permissions to run (unless port < 1024).
- This was written at 2 a.m. so please excuse the errors.
- Encode the flag (e.g., base64).
- Send longer flags by doubling the number of packets sent (use more than one "if" statement in the "for" loop).
- Same as above, but add a sleep statement between the packets.
- instead of a set sleep span, how about sleep span plus a random number?
- embed a timestamp
- Noah Davids - http://noahdavids.org/self_published/beacon.html
- Michael J. Donahoo - http://cs.ecs.baylor.edu/~donahoo/practical/CSockets/code/BroadcastSender.c