From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id a39233bc for ; Fri, 15 Nov 2019 14:31:59 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id A576D9C2EA; Sat, 16 Nov 2019 00:31:57 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 25E8F93DBE; Sat, 16 Nov 2019 00:31:25 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 0083793DAA; Sat, 16 Nov 2019 00:31:22 +1000 (AEST) Received: from mail.cs.Dartmouth.EDU (mail.cs.dartmouth.edu [129.170.212.100]) by minnie.tuhs.org (Postfix) with ESMTPS id 5D44493DA9 for ; Sat, 16 Nov 2019 00:31:22 +1000 (AEST) Received: from coolidge.cs.Dartmouth.EDU (coolidge.cs.dartmouth.edu [129.170.213.217]) by mail.cs.Dartmouth.EDU (8.15.2/8.15.2) with ESMTPS id xAFEVKkY011252 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO) for ; Fri, 15 Nov 2019 09:31:20 -0500 Received: from coolidge.cs.Dartmouth.EDU (localhost [127.0.0.1]) by coolidge.cs.Dartmouth.EDU (8.15.2/8.15.2) with ESMTP id xAFEVKYw029898 for ; Fri, 15 Nov 2019 09:31:20 -0500 Received: (from doug@localhost) by coolidge.cs.Dartmouth.EDU (8.15.2/8.15.2/Submit) id xAFEVKCO029897 for tuhs@tuhs.org; Fri, 15 Nov 2019 09:31:20 -0500 From: Doug McIlroy Message-Id: <201911151431.xAFEVKCO029897@coolidge.cs.Dartmouth.EDU> Date: Fri, 15 Nov 2019 09:31:19 -0500 To: tuhs@tuhs.org User-Agent: Heirloom mailx 12.5 7/5/10 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [TUHS] Happy birthday, Morris worm X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" > That was the trouble; had he bothered to test it on a private network (as > if a true professional would even consider carrying out such an act)[*] he > would've noticed that his probability calculations were arse-backwards Morris's failure to foresee the results of even slow exponential growth is matched by the failure of the critique above to realize that Morris wouldn't have seen the trouble in a small network test. The worm assured that no more than one copy (and occasionally one clone) would run on a machine at a time. This limits the number of attacks that any one machine experiences at a time to roughly the number of machines in the network. For a small network, this will not be a major load. The worm became a denial-of-service attack only because a huge number of machines were involved. I do not remember whether the worm left tracks to prevent its being run more than once on a machine, though I rather think it did. This would mean that a small network test would not only behave innocuously; it would terminate almost instantly. Doug