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Nebula level12

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There is a backdoor process listening on port 50001.

To do this level, log in as the level12 account with the password level12 . Files for this level can be found in /home/flag12.

Source code

 1local socket = require("socket")
 2local server = assert(socket.bind("127.0.0.1", 50001))
 3
 4function hash(password) 
 5  prog = io.popen("echo "..password.." | sha1sum", "r")
 6  data = prog:read("*all")
 7  prog:close()
 8
 9  data = string.sub(data, 1, 40)
10
11  return data
12end
13
14
15while 1 do
16  local client = server:accept()
17  client:send("Password: ")
18  client:settimeout(60)
19  local line, err = client:receive()
20  if not err then
21    print("trying " .. line) -- log from where ;\
22    local h = hash(line)
23
24    if h ~= "4754a4f4bd5787accd33de887b9250a0691dd198" then
25      client:send("Better luck next time\n");
26    else
27      client:send("Congrats, your token is 413**CARRIER LOST**\n")
28    end
29
30  end
31
32  client:close()
33end

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