bandit24 brute forcing program
05AB1E, 9 7 bytes
žh4ã€‚»

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Explanation:

žh       # Push builtin string &quot;0123456789&quot;
  4ã     # Get the cartesian product of 4: [&quot;0000&quot;,&quot;0001&quot;,...,&quot;9998&quot;,&quot;9999&quot;]
    €    # Map each string to:
     ‚   #  Pair it with the (implicit) input-string
      »  # Join each inner list by spaces, and then all strings by newlines
         # (after which the result is output implicitly)