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The `hot-ids` Module

The `hot-ids` module defines a number of redefinable variables that specify usernames Bro should consider sensitive:

  [``forbidden_ids : set[string]``] lists usernames that should never be used. If Bro detects use of one, it will attempt to terminate the corresponding connection.

  Default: `{ "uucp", "daemon", "rewt", "nuucp", "EZsetup", "OutOfBox", "4Dgifts", "ezsetup", "outofbox", "4dgifts", "sgiweb", }`. All of these correspond to accounts that some systems have enabled by default (with well-known passwords), except for `"rewt"`, which corresponds to a username often used by (weenie) attackers.

  Deficiency: The repeated definitions such as `"EZsetup"` and `"ezsetup"` reflect that this variable is a `set` and not a `pattern`. Consequently, the exact username must appear in it (with a pattern, we could use character classes to match both upper and lower case).

  [``forbidden_ids_if_no_password : set[string]``] Same as `forbidden_ids` except only considered forbidden if the login succeeded with an empty password.

  Default: `"lp"`, a default passwordless IRIX account.

  [``forbidden_id_patterns : pattern``] A pattern giving user ids that should be considered forbidden. Deficiency: This pattern is currently only used to check Telnet/Rlogin user ids, not ids seen in other contexts, such as FTP sessions.

  Default: `/(y[o0]u)(r|ar[e3])([o0]wn.*)/`, a particularly egregious style of username of which we've observed variants in different break-ins.

  [``always_hot_ids : set[string]``] A list of usernames that should always be considered sensitive, though not necessarily so sensitive that they should be terminated whenever used.

  Default: `{ "lp", "warez", "demos", forbidden_ids, }`. The `"lp"` and `"demos"` accounts are specified here rather than `forbidden_ids` because it's possible that they might be used for legitimate accounts. `"warez"` (for ``wares'', i.e., bootlegged software) is listed because its use likely constitutes a policy violation, not a security violation.

  Note: `forbidden_ids` is incorporated into `always_hot_ids` to avoid replicating the list of particularly sensitive ids by listing it twice and risking inconsistencies.

  [``hot_ids : set[string]``] User ids that generate alerts if the user logs in successfully.

  Default: `{ "root", "system", always_hot_ids, }`. The ones included in addition to `always_hot_ids` are only considered sensitive if the user logs in successfully.

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