Related to email protocols, clients, servers, content, and message format.

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3
votes
1answer
40 views

Does using the same mail and web server increase a risk of DDos due to IP exposure?

I use the same server for sending my emails and web hosting. I send user registration and support forum mails from my server and occasional marketing mails or newsletters. I read on a CloudFlare blog ...
7
votes
3answers
76 views

Best practices for sending tax data to and from a tax professional

I started doing business with my tax preparers when we all lived in the same city. Recently I moved to a different state. I requested that they send my "Tax Organizer" which contains some personal ...
2
votes
4answers
117 views

Is it possible to fake incoming IP?

I would like to whitelist an IP address on my smtp server so that non-authenticated emails on connections originating from that IP could be routed. I control that other IP, so I can make sure that ...
4
votes
2answers
93 views

Notifying users of a possible security breach

Yesterday, a coworker informed me that a user had opened a malicious e-mail containing a .dotm document which she could not open. I undertook the usual steps to prevent the malware from spreading to ...
3
votes
1answer
163 views

Is it possible to trick a CA into signing a certificate by intercepting on SSL domain validation email?

From my understanding domain validation certificate are verified by receiving an email on some special email addresses on the domain (e.g. postmaster@example.com, admin@example.com) or by sending on ...
1
vote
1answer
71 views

How does MailChimp authenticate emails?

Keeping it short, MailChimp states that: Authentication Should Be Simple Email authentication is useless if it's too hard to implement. Many email service providers require server setup in ...
2
votes
1answer
69 views

Cisco Registered Envelope Service (CRES), big security flaw?

While researching so called HIPAA compliant email providers, I came across Cisco Registered Envelope Service(CRES), which claims to be HIPAA compliant. According to this instruction, upon receiving ...
3
votes
1answer
190 views

Is this encrypted information? Why is it in a URL?

There's a vendor who sends us reports full of links to articles. Some of these links, especially ones that perform what I'm guessing is an HTTP verb of some kind, look like this: ...
57
votes
3answers
6k views

Why do email programs block xml files?

A colleague sent a .xml file to me earlier today, which was blocked by Outlook. As we were discussing the workaround (put it in a .zip), we got to wondering why .xml files are blocked. My colleague ...
0
votes
1answer
66 views

Where email orginates [duplicate]

I keep getting emails from an unknown person. In the header file, I see this: authentication-results: spf=softfail (sender IP is 25.152.82.59) smtp.mailfrom=outlook.com; gmail.com; dkim=none (message ...
18
votes
5answers
4k views

Why would someone want to block images in email?

While there is the possibility that this is just to prevent people from viewing offensive images against their will, somehow I don't think that's the reason why pretty much every email client defaults ...
9
votes
3answers
484 views

Email unsubscribe handling security

There is another question with similar title: Unsubscribe safely however my question addresses completely another issue. I am trying to set up a notification system in the website, that will send ...
2
votes
3answers
2k views

Is it possible to block emails (to all email accounts) that contain certain word/phrase patterns?

A friend of mine has been cyber-stalked for 4 years now by an ex-boyfriend. He recently worked out her new job email address (via LinkedIn) and started sending her emails. She told me that the emails ...
20
votes
3answers
3k views

How does a company like CloudFlare block bot crawling and email harvesters?

I saw this on CloudFlares homepage: CloudFlare protects against a range of threats: cross site scripting, SQL injection, comment spam, excessive bot crawling, email harvesters, and more. How ...
6
votes
1answer
587 views

Gmail lets me use my old password

My university's email works through Gmail and I can log on to it either through my uni's website or in Gmail. I recently changed my password and I use it to log in to the schools secure WiFi, school ...
21
votes
4answers
3k views

Would 'spam' mail really avoid eavesdropping?

spammimic.com offers a service that 'encrypts' your mail as 'spam', the rationale being that all mail services automatically filter out spam, and so if you're wanting to communicate with someone ...
25
votes
6answers
5k views

What real world benefits does PGP have over sending email with SSL/TLS such as with HTTPS?

I've been learning about PGP, and I asked myself, "Why?" For example, if I'm using https://mail.google.com, then what benefit would adding PGP offer that would justify it being used? I can ...
1
vote
0answers
143 views

Attackers on sc.imp.live.com [closed]

"Deceptive site ahead Attackers on sc.imp.live.com may trick you into doing something dangerous like installing software or revealing your personal information (for example, passwords, phone ...
3
votes
4answers
143 views

TLS and e-mail security

Our client has asked us to send sensitive data via TLS and to install a certificate on our mail servers so that they can verify the authenticity of our e-mails. If I understand correctly, TLS ...
3
votes
3answers
64 views

Must mail relays always indicate the use of encryption in the “Received:” header field?

When an email message is sent with transport encryption, you can tell it from the “Received:” field the receiving mail relay adds to the message header. > Received: from [...].google.com ([...]) by ...
0
votes
1answer
207 views

Correct way of dealing with spam via impersonation

I've been having a recurring problem at work: My boss's contacts keep receiving emails with links sent by a fake adress. The adress always has my boss's name + a different domain name every time. ...
2
votes
1answer
57 views

Remembering email in login form

After logging out Google remembers recently used email addresses in the login form so the user only needs to enter the password. See accounts.google.com. How secure is it? What factors should I ...
1
vote
1answer
63 views

Distinct error messages for wrong email / password

I want to continue discussion started in this question "Username and/or Password Invalid" - Why do websites show this kind of message instead of informing the user which one was wrong? but ...
5
votes
2answers
313 views

Why don't banks sign their email using S/MIME?

If email sent by my bank included S/MIME signatures that my mail client can verify, then I would have the assurance that the mail was not tampered with or sent by some malicious third-party. Most ...
6
votes
1answer
279 views

Bank Has Emailed My Social Security Number

I'm in the middle of getting a mortgage. Just now, my bank sent over an e-mail (sent to my Gmail account) with a bunch of .pdf attachments of documents I'm supposed to sign and return. The first ...
0
votes
2answers
50 views

What is the purpose of this “secure mail link open in browser”

I got an email that "supposedly" was secure. It had a link which said that to get secure message follow this link. They could have verified it was me by asking my bank or my smart card to ...
0
votes
2answers
54 views

Using PGP in emails - is there to find the key?

Suppose both the receiver and sender use PGP. Suppose someone send from the sender an email and sent it to the receiver. Now he gets the content of the email at the receiver. Can he know now the keys ...
0
votes
2answers
64 views

Is there a way to use public mail and not to enable the provider to see its content?

I'm looking for a way to use the common public emails such as Google and Yahoo and to prevent them from reading the content of the emails either by application that scans the emails and offer ads or ...
2
votes
1answer
51 views

Mail from Outlook to GMX: via Yahoo? [closed]

On inspecting source of a clear scam mail I received, I noticed that the mail send from Outlook to GMX has somehow passed through Yahoo servers - how come? Is it some way to hide their original ...
0
votes
1answer
65 views

How can I test my spamfilter under real world conditions?

We are currently planning to migrate our outsourced mail solution to our own servers. The last thing we need to test is the spam filter. We are going to use a cloud based spam and anti virus filter ...
27
votes
4answers
17k views

What steps do Gmail, Yahoo! Mail, and Hotmail take to prevent eavesdropping on email?

I would like to ask what happens when an email is sent from gmail, yahoo or hotmail public web email services? I don't understand email protocols in details, but as far as I know email traffic is ...
7
votes
4answers
424 views

How can I convince my communication partner to use encryption in everyday life?

The latest developments made it very clear, how easily basically all communication channels can be wiretapped. However, I think most people still ignore this fact. Especially in business most ...
4
votes
6answers
4k views

How can a non-technical user verify a message was sent “securely”? …or over TLS?

I have a situation where B2B and B2C communication needs to be sent securely and not visible to most SMTP hijackers. I don't care about conspiracy theories or NSA style attacks, but want to provide ...
1
vote
3answers
225 views

What is the simplest way to send an anonymous email?

I would like to send an email that can't be traced back to me, is there a simple direct approach to do that? I mean an electronic way that doesn't involve me going to an Internet cafe wearing a ...
8
votes
3answers
111 views

How can you prevent email addresses from being harvested from a registration form?

When you go to a website's login form and enter the wrong credentials, the website can give you one of three error messages: Your email is wrong Your password is wrong Your email or password is ...
0
votes
1answer
114 views

Sites sending email using my email address

Today I was looking through my spam folder and noticed an email: The sender was myself, assume my email is xxx@gmail.com, on the from section it says xxx@gmail.com via clicktheprofits.com Does ...
1
vote
1answer
59 views

Is it possible to digitally sign an email twice?

User A encrypts an email with the public key of user B and digitally signs it. User B receives this message and decrypts it. B wants to forward it to user C, encrypts it with C's public key and signs ...
5
votes
1answer
371 views

PGP-encrypted Email or SSL/TLS Webform for Responsible Disclosure Communication?

So it's a fairly simple question. When offering an avenue to security researchers for communication with us regarding disclosure of security vulnerabilities, what's the best way to do so? Assume we ...
1
vote
1answer
83 views

Is the following e-mail fraud technically possible?

Summary: Can email be intercepted and modified by a 3rd-party during transit from the sender to the receiver? If so, can this interception be detected? Details: My friend (A) (mailbox at popular ...
54
votes
11answers
11k views

Why would a spammer try to get a (normal) image of mine?

Yesterday I found a spam mail in my inbox. I inspected it in order to find out why DSpam and SpamAssasin failed. You can find the raw German mail here, here's a translation: Good Morning. We got ...
15
votes
3answers
2k views

Somebody is spoofing my email to send spam messages, and I have no idea how to block

Someone is using my Google Apps Email ID to send spam messages and I've received 2000+ undelivered and autorespond emails. I have no idea how to block this because the spammer is also using my email ...
2
votes
3answers
310 views

How do web email clients store my passwords from other providers?

The situation comes down to this: When I enter in hotmail, it retrieves my messages connecting to other providers: they could only do so by using my email and password. Since I had signed in a ...
5
votes
3answers
35k views

Someone keeps using my email address. What to do?

I have had a GMail ever since it was created, so it's an email address that is easy to remember, but also easy for somebody else to get confused with. Since I'm not going to post my email address ...
5
votes
1answer
160 views

I emailed someone a picture of a check I wrote for them. What now?

On a whim, I emailed the intended recipient of a check I wrote a picture of that filled-in check to indicate I was about to mail it out. The full front of the check, with amount, my signature, account ...
53
votes
6answers
9k views

Why do security experts like Snowden use email services like Lavabit and Hushmail rather than self-hosted email?

Why would anyone like Edward Snowden rely on 3rd party services like Lavabit or Hushmail to host his email? I mean it's very easy to set up a self-hosted email server. What you need: Rent VPS (even ...
0
votes
1answer
56 views

Where can emails be sniffed from? [duplicate]

I understand that you should not send private information in emails due, in part, to the fact that this traffic is usually unencrypted and can therefore be sniffed while in transit. Where would a ...
1
vote
1answer
88 views

Is it possible to prove that a forwarded email has been tampered with prior to being forwarded?

I have requested that an old email exchange between myself and HR be forwarded to me by a previous employer. They complied with the request but I suspect that the body of the exchange which they ...
2
votes
2answers
102 views

TLS capable SMTP store-and-forward server — does it have to store private keys?

I know that email is inherently insecure anyway, but considering that pretty much everyone that I send email to is using a large, somewhat-trusted cloud provider, (hint, starts with G) I would expect ...
13
votes
6answers
3k views

Is it a security issue to allow nearly identical email addresses when registering?

Say you have a website where it is possible to create accounts for all of the following email addresses: 'test@test.com' 'test@test.com ' 'test@test.com;' 'test@test.com;test2@test.com' Should this ...
19
votes
7answers
11k views

Forgotten password or reset link, which is more secure to email?

I originally posted this as a reply here in this thread but didn't get much feedback on it, and now I'm curious as to what others think is the best approach, or if there is any difference between the ...