Block Message with blank Subject

[nestortmk]

I have the same problem. Version 7.2-3

Spoiler: Header

Received: from EX2.guma.by (192.168.55.169) by EX1.guma.by
(192.168.55.170) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.16 via EX
Transport; Wed, 25 Jan 2023 16:00:19 +0700
Received: from EX1.guma.by (192.168.55.170) by EX2.guma.by
(192.168.55.169) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.16; Wed, 25 Jan
2023 16:00:19 +0700
Received: from relay.guma.by (192.168.55.233) by EX1.guma.by
(192.168.55.170) with Microsoft SMTP Server id 15.1.2507.16 via Frontend
Transport; Wed, 25 Jan 2023 16:00:19 +0700
Received: from relay.guma.by (localhost.localdomain [127.0.0.1])
by relay.guma.by (Proxmox) with ESMTP id 125D92144C
for <nre@guma.by>; Wed, 25 Jan 2023 16:00:19 +0700 (+07)
Received-SPF: pass (orda.net ... _spf.yandex.ru: Sender is authorized to use 'givi@orda.net' in 'mfrom' identity (mechanism 'include:_spf-ipv4.yandex.ru' matched)) receiver=relay.guma.by; identity=mailfrom; envelope-from="givi@orda.net"; helo=forward105j.mail.yandex.net; client-ip=5.45.198.248
Received: from forward105j.mail.yandex.net (forward105j.mail.yandex.net [5.45.198.248])
by relay.guma.by (Proxmox) with ESMTP id AEF7821452
for <nre@guma.by>; Wed, 25 Jan 2023 16:00:17 +0700 (+07)
Received: from sas1-bf48a613a597.qloud-c.yandex.net (sas1-bf48a613a597.qloud-c.yandex.net [IPv6:2a02:6b8:c14:3327:0:640:bf48:a613])
by forward105j.mail.yandex.net (Yandex) with ESMTP id 5C8064EC9884
for <nre@guma.by>; Wed, 25 Jan 2023 12:00:17 +0300 (MSK)
Received: from mail.yandex.ru (mail.yandex.ru [2a03:d000:6402:b0de:a05f:ec9a:add1:4a92])
by sas1-bf48a613a597.qloud-c.yandex.net (mxback/Yandex) with HTTP id F0LeWI0VSW21-j5JkeOMT;
Wed, 25 Jan 2023 12:00:17 +0300
X-Yandex-Fwd: 1
Authentication-Results: sas1-bf48a613a597.qloud-c.yandex.net; dkim=pass
Received: by wjdchmct5l2sqvhb.sas.yp-c.yandex.net with HTTP;
Wed, 25 Jan 2023 12:00:17 +0300
From:
=?utf-8?B?0J3QtdGB0YLQtdGA0L7QsiDQoNGD0YHQu9Cw0L0g0JXQstCz0LXQvdGM0LXQstC40Yc=?=
<givi@orda.net>
To: <nre@guma.by>
MIME-Version: 1.0
X-Mailer: Yamail [ http://yandex.ru ] 5.0
Date: Wed, 25 Jan 2023 16:00:17 +0700
Message-ID: <2633151674637217@wjdchmct5l2sqvhb.sas.yp-c.yandex.net>
Content-Type: text/plain
X-SPAM-LEVEL: Spam detection results: 2
AWL -2.041 Adjusted score from AWL reputation of From: address
EMPTY_MESSAGE 2.344 Message appears to have no textual parts
KAM_BLANKSUBJECT 0.25 Message has a blank Subject
KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment
MISSING_SUBJECT 1.767 Missing Subject: header
RCVD_IN_MSPIKE_H2 -0.001 Average reputation (+2)
SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record
SPF_PASS -0.001 SPF: sender matches SPF record
Return-Path: givi@orda.net
X-MS-Exchange-Organization-Network-Message-Id: 4c5ffaa1-51d9-4800-a4a9-08dafeb29572
X-MS-Exchange-Organization-AuthSource: EX1.guma.by
X-MS-Exchange-Organization-AuthAs: Anonymous
X-MS-Exchange-Transport-EndToEndLatency: 00:00:00.1590463
X-MS-Exchange-Processed-By-BccFoldering: 15.01.2507.016

Spoiler: Track Log

Jan 25 16:09:59 relay postfix/smtpd[710483]: connect from forward104o.mail.yandex.net[37.140.190.179]

Jan 25 16:09:59 relay postfix/smtpd[710483]: A4D432143B: client=forward104o.mail.yandex.net[37.140.190.179]

Jan 25 16:09:59 relay postfix/cleanup[710345]: A4D432143B: message-id=<4908441674637799@xs3ef5pge24bajlc.myt.yp-c.yandex.net>

Jan 25 16:09:59 relay postfix/qmgr[696815]: A4D432143B: from=<givi@orda.net>, size=1698, nrcpt=1 (queue active)

Jan 25 16:09:59 relay postfix/smtpd[710483]: disconnect from forward104o.mail.yandex.net[37.140.190.179] ehlo=1 mail=1 rcpt=1 data=1 quit=1 commands=5

Jan 25 16:09:59 relay pmg-smtp-filter[710795]: 2144763D0F1E7BE82B: new mail message-id=<4908441674637799@xs3ef5pge24bajlc.myt.yp-c.yandex.net>#012

Jan 25 16:10:04 relay pmg-smtp-filter[710795]: 2144763D0F1E7BE82B: SA score=1/5 time=4.174 bayes=undefined autolearn=no autolearn_force=no hits=AWL(-1.033),HTML_MESSAGE(0.001),HTML_MIME_NO_HTML_TAG(0.635),KAM_BLANKSUBJECT(0.25),KAM_DMARC_STATUS(0.01),MIME_HTML_ONLY(0.1),MISSING_SUBJECT(1.767),RCVD_IN_MSPIKE_H2(-0.001),SPF_HELO_NONE(0.001),SPF_PASS(-0.001)

Jan 25 16:10:04 relay postfix/smtpd[710644]: connect from localhost.localdomain[127.0.0.1]

Jan 25 16:10:04 relay postfix/smtpd[710644]: 034EC213CC: client=localhost.localdomain[127.0.0.1], orig_client=forward104o.mail.yandex.net[37.140.190.179]

Jan 25 16:10:04 relay postfix/cleanup[710347]: 034EC213CC: message-id=<4908441674637799@xs3ef5pge24bajlc.myt.yp-c.yandex.net>

Jan 25 16:10:04 relay postfix/qmgr[696815]: 034EC213CC: from=<givi@orda.net>, size=2622, nrcpt=1 (queue active)

Jan 25 16:10:04 relay postfix/smtpd[710644]: disconnect from localhost.localdomain[127.0.0.1] ehlo=1 xforward=1 mail=1 rcpt=1 data=1 commands=5

Jan 25 16:10:04 relay pmg-smtp-filter[710795]: 2144763D0F1E7BE82B: accept mail to <nre@guma.by> (034EC213CC) (rule: default-accept)

Jan 25 16:10:04 relay pmg-smtp-filter[710795]: 2144763D0F1E7BE82B: processing time: 4.285 seconds (4.174, 0.032, 0)

Jan 25 16:10:04 relay postfix/lmtp[708855]: A4D432143B: to=<nre@guma.by>, relay=127.0.0.1[127.0.0.1]:10024, delay=4.4, delays=0.07/0/0.04/4.3, dsn=2.5.0, status=sent (250 2.5.0 OK (2144763D0F1E7BE82B))

Jan 25 16:10:04 relay postfix/qmgr[696815]: A4D432143B: removed

Jan 25 16:10:04 relay postfix/smtp[710645]: 034EC213CC: to=<nre@guma.by>, relay=192.168.55.170[192.168.55.170]:25, delay=0.19, delays=0.05/0/0/0.13, dsn=2.6.0, status=sent (250 2.6.0 <4908441674637799@xs3ef5pge24bajlc.myt.yp-c.yandex.net> [InternalId=8061653615123, Hostname=EX2.guma.by] 3927 bytes in 0.119, 32.140 KB/sec Queued mail for delivery)

Jan 25 16:10:04 relay postfix/qmgr[696815]: 034EC213CC: removed

If you specify words in the subject in the conditions, the rule works out

Spoiler: Worked

Jan 25 15:34:11 relay postfix/smtpd[708372]: connect from forward106j.mail.yandex.net[5.45.198.249]
Jan 25 15:34:11 relay postfix/smtpd[708372]: 34839213E1: client=forward106j.mail.yandex.net[5.45.198.249]
Jan 25 15:34:11 relay postfix/cleanup[708493]: 34839213E1: message-id=<2504901674635645@2kmipagb6w7jjvhg.sas.yp-c.yandex.net>
Jan 25 15:34:11 relay postfix/qmgr[696815]: 34839213E1: from=<givi@orda.net>, size=1711, nrcpt=1 (queue active)
Jan 25 15:34:11 relay postfix/smtpd[708372]: disconnect from forward106j.mail.yandex.net[5.45.198.249] ehlo=1 mail=1 rcpt=1 data=1 quit=1 commands=5
Jan 25 15:34:11 relay pmg-smtp-filter[708532]: 2142863D0E9837C570: new mail message-id=<2504901674635645@2kmipagb6w7jjvhg.sas.yp-c.yandex.net>#012
Jan 25 15:34:12 relay pmg-smtp-filter[708532]: 2142863D0E9837C570: SA score=0/5 time=0.700 bayes=undefined autolearn=ham autolearn_force=no hits=AWL(-1.087),HTML_MESSAGE(0.001),HTML_MIME_NO_HTML_TAG(0.635),KAM_DMARC_STATUS(0.01),MIME_HTML_ONLY(0.1),RCVD_IN_DNSWL_LOW(-0.7),RCVD_IN_MSPIKE_H2(-0.001),SPF_HELO_NONE(0.001),SPF_PASS(-0.001)
Jan 25 15:34:12 relay pmg-smtp-filter[708532]: 2142863D0E9837C570: notify <givi@orda.net> (rule: Empty Subject Reject, 4AF8421436)
Jan 25 15:34:12 relay pmg-smtp-filter[708532]: 2142863D0E9837C570: block mail to <nre@guma.by> (rule: Empty Subject Reject)
Jan 25 15:34:12 relay pmg-smtp-filter[708532]: 2142863D0E9837C570: processing time: 0.844 seconds (0.7, 0.066, 0)
Jan 25 15:34:12 relay postfix/lmtp[707623]: 34839213E1: to=<nre@guma.by>, relay=127.0.0.1[127.0.0.1]:10024, delay=1.2, delays=0.08/0/0.23/0.85, dsn=2.7.0, status=sent (250 2.7.0 BLOCKED (2142863D0E9837C570))
Jan 25 15:34:12 relay postfix/qmgr[696815]: 34839213E1: removed

If Subject =^$, also does not work

 

[MiamiJack]

I can't tell you if that would work within the GUI, however I think you can probably create a SpamAssassin Rule to flag it.

 

[nestortmk]

I can't tell you if that would work within the GUI, however I think you can probably create a SpamAssassin Rule to flag it.

Sorry, I do not understand where and how to do this (((

 

[MiamiJack]

I don't have the rule coding, but you would create the spamassasin rule to look for an empty/blank subject and add it to
/etc/mail/spamassassin/custom.cf Which is where you place your custom rules.

Now if you have never done this and not comfortable, I get it, but thats the only way to add specialized control / rules, I use that with certain types of spam I'm trying to block.

NOTE: I'm not sure thats a good thing to block as I get many legit users ( not people very technical ) sending blank subjects.

Here is a page that has a couple of examples of the rule, but MAKE SURE YOU TEST... otherwise you may be rejecting more than you want.

https://users.spamassassin.apache.narkive.com/03kxVet4/empty-subject-suspected-as-spam

 

[nestortmk]

Checked. The rule is working. But only for Gmail. Yandex or mail.ru skips