diff --git a/lib/libutil/gr_util.c b/lib/libutil/gr_util.c
index 0173595c24d0..323d3ff8ee3e 100644
--- a/lib/libutil/gr_util.c
+++ b/lib/libutil/gr_util.c
@@ -63,6 +63,8 @@ static const char group_line_format[] = "%s:%s:%ju:";
 int
 gr_init(const char *dir, const char *group)
 {
+	struct stat st;
+
 	if (dir == NULL) {
 		strcpy(group_dir, _PATH_ETC);
 	} else {
@@ -88,6 +90,15 @@ gr_init(const char *dir, const char *group)
 		}
 		strcpy(group_file, group);
 	}
+
+	if (stat(group_file, &st) == -1)
+		return (-1);
+
+	if (S_ISDIR(st.st_mode)) {
+		errno = EISDIR;
+		return (-1);
+	}
+
 	initialized = 1;
 	return (0);
 }
diff --git a/lib/libutil/pw_util.c b/lib/libutil/pw_util.c
index 4bf3001ffe79..6013e6d0640f 100644
--- a/lib/libutil/pw_util.c
+++ b/lib/libutil/pw_util.c
@@ -96,6 +96,7 @@ pw_init(const char *dir, const char *master)
 #if 0
 	struct rlimit rlim;
 #endif
+	struct stat st;
 
 	if (dir == NULL) {
 		strcpy(passwd_dir, _PATH_ETC);
@@ -123,6 +124,14 @@ pw_init(const char *dir, const char *master)
 		strcpy(masterpasswd, master);
 	}
 
+	if (stat(masterpasswd, &st) == -1)
+		return (-1);
+
+	if (S_ISDIR(st.st_mode)) {
+		errno = EISDIR;
+		return (-1);
+	}
+
 	/*
 	 * The code that follows is extremely disruptive to the calling
 	 * process, and is therefore disabled until someone can conceive