Jun 30 11:43:00 bottom sm-mta[18852]: AUTH: available mech=DIGEST-MD5 CRAM-MD5 LOGIN PLAIN, allowed mech=EXTERNAL
Jun 30 11:43:00 bottom sm-mta[18852]: AUTH: available mech=DIGEST-MD5 CRAM-MD5 LOGIN PLAIN, allowed mech=EXTERNAL
Update here, it's not apparently an STARTTLS error, it's an AUTH
error. Something in the update last night altered my list of
available AUTH mechanisms.
I manually updated sendmail.cf and updated this line:
O AuthMechanisms=EXTERNAL DIGEST-MD5 CRAM-MD5 NTLM LOGIN PLAIN
by adding "DIGEST-MD5 CRAM-MD5 NTLM LOGIN PLAIN" and now it accepts
mail from my desktop.
I don't see where this is configured. /etc/sasl2/Sendmail.conf which
is a link to /etc/mail/sasl/Sendmail.conf.2, but this file looks good,
I don't know where it's getting the AuthMechanisms from (yet).
After an update today, sendmail is refusing to accept mail. I'm
seeing this in the logs:
On Sun, 30 Jun 2024, Michael Grant wrote:
After an update today, sendmail is refusing to accept mail. I'm
seeing this in the logs:
Hmmm, this update seems to have done a lot of odd things.
On Sun, 30 Jun 2024, Michael Grant wrote:
After an update today, sendmail is refusing to accept mail. I'm
seeing this in the logs:
Hmmm, this update seems to have done a lot of odd things.
MSP Queue status...
/var/spool/mqueue-client (2 requests)
-----Q-ID----- --Size-- -----Q-Time----- ------------Sender/Recipient-----------
45U9e1iI018145 30770 Sun Jun 30 10:40 MAILER-DAEMON
(Deferred: 421 4.5.0 Bare carriage return (CR) not allowed)
root
45U5Qnln008885 28799 Sun Jun 30 06:26 root
7BIT (Deferred: 421 4.5.0 Bare carriage return (CR) not allowed)
root
Total requests: 2
MTA Queue status...
/var/spool/mqueue is empty
Total requests: 0
That's the cron email telling me about the update.
It's not at all clear to me what it's complaining about. root@dirac:/var/spool/mqueue-client# od -t x1 qf45U* | grep 0d root@dirac:/var/spool/mqueue-client#
Unless it's the bare CR in the body of the email - which should be fine!
Moving the queue files from mqueue-client to mqueue and fixing up the
owner and perms and they delivered fine.
According to this https://support.trustwave.com/kb/KnowledgebaseArticle10016.aspx
bare CRs aren't allowed in emails but this has always worked.
I'm only likely to have cron generating emails like this.
Strange that this would have been changed in a stable release. It
doesn't seem to have been a security update.
On Sun, Jun 30, 2024 at 23:08:01 +0100, Tim Woodall wrote:
According to this
https://support.trustwave.com/kb/KnowledgebaseArticle10016.aspx
bare CRs aren't allowed in emails but this has always worked.
I'm only likely to have cron generating emails like this.
Strange that this would have been changed in a stable release. It
doesn't seem to have been a security update.
It looks like it's coming from this change:
https://metadata.ftp-master.debian.org/changelogs//main/s/sendmail/sendmail_8.17.1.9-2+deb12u2_changelog
* Fix CVE-2023-51765 (Closes: #1059386):
sendmail allowed SMTP smuggling in certain configurations.
Remote attackers can use a published exploitation
technique to inject e-mail messages with a spoofed
MAIL FROM address, allowing bypass of an SPF protection
mechanism. This occurs because sendmail supports
<LF>.<CR><LF> but some other popular e-mail servers
do not. This is resolved with 'o' in srv_features.
I don't know the details of how this leads to a security hole.
Yeah I'm seeing this too! Identical in fact. This is what I did to
fix this: I added this to my /etc/mail/access file for my local
server that sends this messages to me:
SRV_Features:127.0.0.1 L U G
Specifically, I added the U and G features, (I already had the L
feature disabled for localhost). Uppercase letter disables the
feature, lowercase enables it.
I found the U and G mentioned here:
https://forums.oracle.com/ords/apexds/post/solaris-11-4-sendmail-issue-after-sendmail-8-18-1-update-7312
I did not try this suggestion to use U2 and G2 that he mentioned. If
you do let me know.
On Sun, 30 Jun 2024 at 23:21, Tim Woodall <debianuser@woodall.me.uk> wrote:
like this. Seems to me that sendmail is.
The thing I'm seeing is <CR> in the body of the email - I had no idea
this was illegal - and I'm surprised that tools like cron don't do
something to avoid sending "illegal" emails. Indeed, even mail will do
so happily.
cron isn?t a mail sending tool ? not the right place to police something
Mark
On Sun, 30 Jun 2024, Michael Grant wrote:
Yeah I'm seeing this too! Identical in fact. This is what I did to
fix this: I added this to my /etc/mail/access file for my local
server that sends this messages to me:
SRV_Features:127.0.0.1 L U G
Specifically, I added the U and G features, (I already had the L
feature disabled for localhost). Uppercase letter disables the
feature, lowercase enables it.
I found the U and G mentioned here:
https://forums.oracle.com/ords/apexds/post/solaris-11-4-sendmail-issue-after-sendmail-8-18-1-update-7312
I did not try this suggestion to use U2 and G2 that he mentioned. If
you do let me know.
Thanks!
I've just added u2 g2 and it seems to work. My quick test had bare LF
removed and bare CR replaced by space which isn't what I expected but is
good enough...
cron isn’t a mail sending tool — not the right place to police something like this. Seems to me that sendmail is.
On Sun, 30 Jun 2024, Tim Woodall wrote:
On Sun, 30 Jun 2024, Michael Grant wrote:Actually, in bookworm this only seems to work with cr. mail wasn't
Yeah I'm seeing this too! Identical in fact. This is what I did to
fix this: I added this to my /etc/mail/access file for my local
server that sends this messages to me:
SRV_Features:127.0.0.1 L U G
Specifically, I added the U and G features, (I already had the L
feature disabled for localhost). Uppercase letter disables the
feature, lowercase enables it.
I found the U and G mentioned here:
https://forums.oracle.com/ords/apexds/post/solaris-11-4-sendmail-issue-after-sendmail-8-18-1-update-7312
I did not try this suggestion to use U2 and G2 that he mentioned. If
you do let me know.
Thanks!
I've just added u2 g2 and it seems to work. My quick test had bare LF
removed and bare CR replaced by space which isn't what I expected but is
good enough...
sending a lf and my email client was not displaying ^f
This works for testing cr and lf.
echo -ne 'Subject: test\n\ncr\rcr/lf\nlf' | /usr/sbin/sendmail -i -- root
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 546 |
Nodes: | 16 (2 / 14) |
Uptime: | 03:10:33 |
Calls: | 10,386 |
Calls today: | 1 |
Files: | 14,057 |
Messages: | 6,416,595 |