diff -urpN JohnTheRipper.orig//src/sip_fmt_plug.c JohnTheRipper/src/sip_fmt_plug.c
--- JohnTheRipper.orig//src/sip_fmt_plug.c	2013-05-02 16:52:36.000000000 +0000
+++ JohnTheRipper/src/sip_fmt_plug.c	2013-05-02 22:33:26.000000000 +0000
@@ -82,6 +82,8 @@ static int valid(char *ciphertext, struc
 	int res = 0;
 	if (strncmp(ciphertext, "$sip$*", 6))
 		return 0;
+	if (strspn(ciphertext, "*") != 14)
+		return 0;
 	if (strlen(ciphertext) > 2048) // sizeof(saltBuf) in get_salt
 		return 0;
 	p += 6;