Simple Mail Transfer Protocol. A protocol for delivering e-mail from an end user to a server for storage and later retrieval by the intended recipient.
Questions tagged [smtp]
172 questions
5
votes
1 answer
SMTP injection, how it is done and what can it cause?
There are a few things that I dont understand about the injection.
The injection is something along this line
> .
MAIL FROM: mail1@gmail.com
RCPT TO: mail@gmail.com
DATA
EMAIL data
.
Here are two ways to inject in an inline…
Kratos
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4
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1 answer
Checklist for securing smtp
What are some things, one should know when setting up an SMTP server, which supports ESMTP protocol. I have disabled relaying, and only enabled TLS authenticated transfers.
when I telnet to my server, this is the…
marcoo
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3
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1 answer
is there a risk in increasing esmtp header line length against rfc5822 - asa/pix question
Have a question towards the 998 bytes limitation on the esmtp header line length.
We have noticed the asa is dropping emails coming from various external mail servers with the header line length greater than 998.
Have googled a bit on this issue and…
user4565
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3
votes
2 answers
SPF and Articles from News Sites
Suppose I activate SPF in my environment. I am now strictly enforcing SPF records from sending domains. There are many execs in the company who like to forward news stories from CNN and such to their co-workers. When I send the article, CNN asks…
ChrisLoris
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Is there a list of open mail relays I can use for a pentest?
I'm currently pentesing a client (with permission of course) and we are testing their email filtering capabilities. We want to check whether they reject mail coming from open mail relays, but I seem unable to find any. Is there a list somewhere that…
trallgorm
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3
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3 answers
How to know an SMTP server is securely configured
I have set up an SMTP server for personal use, and I used Postfix for that. However, Postfix has a lot of different options for how to configure it, and I'm guessing by configuring it incorrectly you can open it up to a lot of security problems,…
Dragon Creature
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Where to find mails or mail addresses on a web server?
In a training lab I'm using for a computing security certification I just got root access to a SMTP server, and there are so much files to look for. I want to retrieve mails or mail addresses using or stored by this SMTP server.
Here are some…
Stephane
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vote
3 answers
Is VRFY command enabled on SMTP server usually considered a vulnerability?
Messing around I found a critical SMTP server with VRFY command enabled.
penguin
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0
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1 answer
Receiving strange data over SMTP where body is one line of random characters
I have a website that has an smtp server open on port 25. There is no outbound functionality on the smtp server. We just parse attachments from our users, then 'queue' the email in a dummy queue. So essentially we drop the email after parsing…
user52355
0
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0 answers
Suspicious SMTP server client activity - non-ASCII queries
I've noticed some strange activities from some remote host connected to our SMTP mail server. Queries contains non-ASCII characters, below is the copy of one of them (to each query our server responded with "command not…
Ernestas Gruodis
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What are recommendations for unblocking outbound SMTP traffic in an organization?
Our organization has blocked all outbound SMTP traffic under the assumption that we are preventing potential botnet spamming issues which lead to blacklisted IPs. However, I've seen other organizations which have been set up to allow this and am…
bjb
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smtp port 25 connect failed
If I take any host from
https://www.arclab.com/en/kb/email/list-of-smtp-and-pop3-servers-mailserver-list.html
why I'm not able to telnet to any of the specified ports ? I'm getting:
"Connecting To pop.1and1.com...Could not open connection to the…
cyzczy
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smtp-auth attack ?
it looks someone or something is trying to hack our Exchange.
Exchange Server Transport Protocol Logs:
it appears the internet facing IP on the firewall has not been locked down correctly, so is open to all internet traffic (the network team will…
cyzczy
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