Subject: Alternate Security Fix: Shadow
From: [email-masked] (lilo)
Date: Thu, 19 May 1994 16:19:06 GMT
Newsgroups: comp.os.linux.announce

Hi, all--

Per Alan Cox's previous warning, it is possible to gain unauthorized access
to most Linux systems via telnetd/rlogind using the trick previous
mentioned.  I'd strongly recommend getting the patched utilities from Alan!
But for those of you who are running Shadow 3.3.2 and have the source handy,
I'm including this quick patch which might also be useful.

Note:  This completely disables the ability of root to use login to sign
onto users' accounts without specifying a password.  It doesn't affect su at
all; so it might be a good idea to apply it in any case!  ;)

 --lilo

--- lmain.c.VIRGIN	Wed May 18 11:55:53 1994
+++ lmain.c	Wed May 18 12:14:22 1994
@@ -403,7 +403,9 @@
 				break;
 			case 'f':
 				fflg++;
+#ifdef PREAUTH_ALLOWED
 				preauth_flag++;
+#endif
 				STRFCPY (name, optarg);
 				break;
 #ifdef	RLOGIN
@@ -417,8 +419,10 @@
 #ifdef	SVR4
 				STRFCPY (utxent.ut_host, optarg);
 #endif	/* SVR4 */
+#ifdef PREAUTH_ALLOWED
 				if (rlogin (host, name, sizeof name))
 					preauth_flag++;
+#endif
 
 				break;
 			case 'h':

--
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