From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nekare.kjorling.se (nekare.kjorling.se [89.221.249.175]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.server123.net (Postfix) with ESMTPS for ; Mon, 24 Apr 2017 19:44:13 +0200 (CEST) Received: from yeono.kjorling.se (h-9-65.a328.priv.bahnhof.se [46.59.9.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "yeono", Issuer "yeono" (not verified)) by nekare.kjorling.se (Postfix) with ESMTPS id 1C0B3114510 for ; Mon, 24 Apr 2017 17:44:05 +0000 (UTC) Received: from yeono.kjorling.se (localhost [127.0.0.1]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by yeono (Postfix) with ESMTPS id AD63A1B0F for ; Mon, 24 Apr 2017 19:44:05 +0200 (CEST) Date: Mon, 24 Apr 2017 17:44:04 +0000 From: Michael =?utf-8?B?S2rDtnJsaW5n?= Message-ID: <20170424174404.GF27789@yeono.kjorling.se> References: <20170422002548.GA23882@tansi.org> <20170422134557.GB1425@tansi.org> <56144922-1d2e-b97c-3a5b-d7a952c84950@depressiverobots.com> <6bbee653-87c7-7145-82fe-785ab6fafece@depressiverobots.com> <569e04ca-10ae-28fc-9db2-5bf0cb9daea5@depressiverobots.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Subject: Re: [dm-crypt] LUKS header recovery attempt, bruteforce detection of AF-keyslot bit errors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On 24 Apr 2017 18:00 +0100, from dominic@timedicer.co.uk (Dominic Raferd): > Is there any possibility that a malicious third party (disgruntled > ex-sysadmin perhaps) gained root access to the machine during its last > session and changed the passphrase? Does that not require knowledge of a current passphrase? I believe it does. Which of course said third party _could_ have. > As an aside, of no help to OP I'm afraid: is a prior backup of the > LUKS header a protection against this scenario (i.e. against a > subsequently deleted, or changed and now unknown, passphrase)? Yes. A copy of the LUKS header and a passphrase that was valid at the time the header copy was made will allow access, as long as the master key is unchanged (no cryptsetup-reencrypt in the interim). The only way to mitigate this threat AFAIK is to change the master key of the container. -- Michael Kjörling • https://michael.kjorling.se • michael@kjorling.se “People who think they know everything really annoy those of us who know we don’t.” (Bjarne Stroustrup)