7.  Security

The uucp system, left unrestricted, will let any outside user execute any commands and copy in/out any file which is readable/writable by the uucp login user. It is up to the individual sites to be aware of this and apply the protections that they feel are necessary.

There are several security features available aside from the normal file mode protections. These must be set up by the installer of the uucp system.

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The login for uucp does not get a standard shell. Instead, the uucico program is started. Therefore, the only work that can be done is through uucico.

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A path check is done on file names that are to be sent or received. The USERFILE supplies the information for these checks. The USERFILE can also be set up to require call-back for certain login-ids. (See the ``Files required for execution'' section for the file description.)

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A conversation sequence count can be set up so that the called system can be more confident that the caller is who he says he is.

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The uuxqt program comes with a list of commands that it will execute. A ``PATH'' shell statement is prepended to the command line as specifed in the uuxqt program. The installer may modify the list or remove the restrictions as desired.

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The L.sys file should be owned by uucp and have mode 0400 to protect the phone numbers and login information for remote sites. (Programs uucp, uucico, uux, uuxqt should be also owned by uucp and have the setuid bit set.)