Patch by for dsniff >= 2.4b1, which adds a memset to correctly 0 out the C struct. --- dsniff-2.4/msgsnarf.c 2011-10-09 18:13:49.000000000 +0200 +++ dsniff-2.4/msgsnarf.c.segfault 2011-10-09 18:25:26.000000000 +0200 @@ -584,6 +584,7 @@ if (i == 0) { if ((c = malloc(sizeof(*c))) == NULL) nids_params.no_mem("sniff_msgs"); + memset(c, 0, sizeof(*c)); c->ip = ts->addr.saddr; c->nick = strdup("unknown"); SLIST_INSERT_HEAD(&client_list, c, next);