chkrootkit is a tool to locally check for signs of a rootkit.  It
contains:

 * chkrootkit: a shell script that checks system binaries for
   rootkit modification.
 * ifpromisc.c: checks if the network interface is in promiscuous
   mode.
 * chklastlog.c: checks for lastlog deletions.
 * chkwtmp.c: checks for wtmp deletions.
 * check_wtmpx.c: checks for wtmpx deletions.  (Solaris only)
 * chkproc.c: checks for signs of LKM trojans.
 * chkdirs.c: checks for signs of LKM trojans.
 * strings.c: quick and dirty strings replacement.