Use of userid and password information obtained illicitly from one host (e.g. downloading a file of account IDs and passwords, tapping TELNET, etc.) to compromise another host. Also, the act of TELNETting through one or more hosts in order to confuse a trace (a standard cracker procedure).
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Nearby terms: leaky heap « Lean « LEAP « leapfrog attack » leap second » learning curve » leased line