On Fri, 2002-11-22 at 06:36, Alexander Neumann wrote: > John Goerzen wrote: > > GRUNT is a tool to let you execute commands remotely, offline. > > It will also let you copy files to a remote machine. > > How did you solve the problem of re-sending such mails? Say, Joe Evil > Cracker is able to catch a command mail containing "halt". Will he be > able to shutdown my machine every time he want? I can't speak for GRUNT (having no first-hand knowledge of it) but a couple of ways to do this spring to mind. For example, timestamp every message internally (so the timestamp is inside the GPG payload, not just in the header) and keep a record at the recipient end of timestamps of all executed commands. Ignore duplicates. Alternatively a random character string could be used, but timestamps might give other benefits (for eg, ignore messages older than 5 minutes). Jonathan Oxer Ph +61 3 9723 9399 / Fx +61 3 9723 4899 GPG key: http://www.ivt.com.au/gpg/jon.oxer.gpg
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