S/MIME: BAD HEADER SECTION, Duplicate header field: "MIME-Version" in Kopano 11.0.1
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The issue mentioned in S/MIME: BAD HEADER SECTION, Duplicate header field: “MIME-Version” still persists in the Kopano 11.0.1 nightly build.
The problem with sending email with malformed headers is that some mail filters are configured to flag such email as spam or right out reject them.
The duplication of the
MIME-Version:field happens when mail is signed but not encrypted. When comparing a header from a signed email with a header from an encrypted email it appears that it is the secondMIME-Version:field inserted in-between theMessage-Id:andContent-Type:that should not be there, see examples below:Email signed but not encrypted result in duplicated
MIME-Version:fields:Return-Path: <demo@example.com> Received: from mx.example.com (172.19.0.4:55360) by 508f7e0cf0cd (kopano-dagent) with LMTP; Tue, 20 Apr 2021 09:36:30 +0200 (CEST) Received: from 508f7e0cf0cd (demo_app_1.demo_backend [172.19.0.5]) by mx.example.com (Postfix) with ESMTP id CE0F6C72 for <demo@example.com>; Tue, 20 Apr 2021 09:36:29 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=example.com; s=default; t=1618904190; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:mime-version: content-type:content-type; bh=4ntlQ8FsYEsN5yJpC6ongq8pKon9JGuz8jUUc1WG7G0=; b=Vg3BsI2MWLuhGU/l/9NSH3/9hlLeRufkhMezU8LAcl/6/DjMbrpDE9OZEW7cXMAj76+pxa joAwF3mzteNaWsOD3KiCrBi49cHkr+rwk2IuyMrhcrzgN4KNbzbgwTVbpCXTMcpRsNnGNA ETDB5EmsuCAF/ui1g7aibgiU/kIA19gLqoZGo5EPLsJfTgyy7dr3ZooY9c04oF/RiPponI X0xwR5wpY6+TdIZ9V1sXU6rrEMVDTXFgueFPSJya0K+qATD9cluwGNpWFUjLHd3tbpgS5v DR/iuGC9O3s7rc0I8yAYNdPfnnjiCmKuLl0wKMQtlfxEybhAGM64tshzp8Nkdg== Received: by 508f7e0cf0cd (kopano-spooler) with MAPI; Tue, 20 Apr 2021 09:36:29 +0200 Subject: test1 From: "demo" <demo@example.com> To: "demo" <demo@example.com> Date: Tue, 20 Apr 2021 07:36:29 +0000 Mime-Version: 1.0 X-Priority: 3 (Normal) X-Mailer: Kopano 11.0.1 Thread-Index: AYD8WeC3zeGAq02kQEeSaQMMJQ7kuA== Message-Id: <kcEE.PH9uemIDSLe4ZCChXIVFrg.gPxZ4Lc11wE@508f7e0cf0cd> MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg="sha-256"; boundary="----E3330E1FE339C1EB99D00FCF9F2025F9"Encrypted email does not result in duplicated
MIME-Version:fields:Return-Path: <demo@example.com> Received: from mx.example.com (172.19.0.4:55410) by 508f7e0cf0cd (kopano-dagent) with LMTP; Tue, 20 Apr 2021 09:38:35 +0200 (CEST) Received: from 508f7e0cf0cd (demo_app_1.demo_backend [172.19.0.5]) by mx.example.com (Postfix) with ESMTP id 02FB3CEF for <demo@example.com>; Tue, 20 Apr 2021 09:38:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=example.com; s=default; t=1618904315; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wqyLX8iv+pWfBCNkj45xWbdDqFG2+OpnQGjech/Xoyo=; b=NQ/IECmjgj+vm13GDaiiXor/+9b0JXjZETRj9exvELOsk6Xm9Aqc0WdIBQXNTfAKAcICVT nVpxTKL3EheaQE/EFKkChzeJHOmENF+3f7Rv9nmyUUvoNNLoHpFiLtYVi6gcS3SqFs8uzQ r2bP52qsOGaYMhWbkySsVDmLHsq8Z/g7NmdnCH5SvnBhgfNoi63nqE58am4R43r6oudqRY H1LgTZ3DphQ8e4YaU+JSYKkIL1WVV8/EbfobPIQ3/mfImnpC1SzDaSq7SCPjygesv/p6w1 VYmngrrh26VHddnaH+xEc1y6ctK91YiHyNAgx1t4IJuTSE9tk+jIJWhf5kt1zQ== Received: by 508f7e0cf0cd (kopano-spooler) with MAPI; Tue, 20 Apr 2021 09:38:34 +0200 Subject: test3 From: "demo" <demo@example.com> To: "demo" <demo@example.com> Date: Tue, 20 Apr 2021 07:38:34 +0000 Mime-Version: 1.0 X-Priority: 3 (Normal) X-Mailer: Kopano 11.0.1 Thread-Index: AQB52yq4dMQ2TZz+SnK2J44aWOoKjA== Content-Type: application/x-pkcs7-mime; name=smime.p7m; smime-type=enveloped-data Content-Transfer-Encoding: base64 Message-Id: <kcEE.JzWnun+/RcSKNIfAe9D/Ug.AHnbKrg11wE@508f7e0cf0cd> -
The issue mentioned here still persists in the Kopano 11.0.2 nightly build.
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@lantz Hi. Thanks for reporting this, I am currently investigating the issue
