I work for a hotel. The hotel stores a MySQL database online. This database only contains a Reference ID, number of nights and so on, but no private data. No names, no personal information on guests. So if it fully leaks, it doesn't matter as much.

Then I have a new laptop (Windows 10), with Bitdefender and Zone Alarm. This laptop does not have any other software installed other than Microsoft Office nor is it used for anything else but one purpose.

The laptop has a .xls with customer names, phone numbers, email addresses in cleartext. A small Visual Basic program I wrote sends a feedback email (via SMTP) to each guest after their stay.

Now my questions are as follows:

  1. Is this setup safer than storing encrypted versions of their emails and phone numbers in the MySQL database?

  2. Since the IP of the laptop leaks when an email is sent via SMTP (an attacker would know the local IP) is there a risk of somebody attacking the laptop via the internet?

  3. Would it be safer to deploy the .xls and the macro on a Windows based server?

  4. How safe is this type of setup, what would your thoughts and advice be?

Keep in mind that I do have to be able to retrieve the emails and phone numbers on the laptop in order to send the emails.

  • Is your laptop encrypted? Preferably with full drive encryption (FDE) such as bitlocker or similar?
    – TTT
    May 16, 2016 at 16:10
  • Yes, BitLocker. My concern is that somebody could take over the laptop and through some sort of attack on the IP could get access and simply copy-paste the file, or open it and copy the content. Because I have access to the file - and I need to retain access since I need to send to the cleartext email address of each customer the feedback email. Physical access is not an issue, just access over the internet.
    – Delia
    May 16, 2016 at 16:18

1 Answer 1


Generally speaking, storing that information in the DB, encrypted is the better choice. Is there any reason you are not doing this?

I would be less worried about an attacker trying to attack the Laptop via a leaked Local IP since most laptops don't allow incoming connections, I would be more concerned about a person clicking a link which compromises the computer, allowing an attacker full access.

For question three, yes, generally, these systems are monitored, and locked down. If all it has is arbitrary stay information, than having it on the server system is better. I would assume you get their info from another DB? Even if you generate the XLMS on the server and have a script run, it's better than have it on one persons laptop.

The setup's safety is relative to the person managing the system. For instance, I as a Info Sec person, generally, have a more secure laptop than a lot of Small, Medium businesses. However, your admin should be following some basic best practices, which should increase the overall security of the server, so unless you are a paranoid Info Sec Bod, with an encrypted HDD, and 12 char password, who takes regular backups of files, than you "might" be fine, but from a business standpoint, no user laptop should run business functionality.

  • Hi Shane, Nobody has access to the actual laptop. It is a special one-purpose laptop. I never use that laptop for anything else. It has this dedicated purpose. I do not store the information on the server to restrict access to it. The only information I store on the server is generic, and leaking it would not affect me. I want to have maximum security (the new EU data protection fine is up to 20 million so better to be safe).
    – Delia
    May 16, 2016 at 16:23
  • Would it be better not to connect to SMTP directly but through something like postmark thus avoiding leaking the IP? Or maybe a SMTP forwarding service or using a VPN? This was nobody would know my real local IP?
    – Delia
    May 16, 2016 at 16:25
  • So you are using it more as a server it seems. I am less familiar with EU's data protection laws, I would say you may want to look at the EU compliance for the data, and as long as you meet the requirements your fine. The platform by which the data rests is less of a concern. I would add that Server installs by default are generally more secure by default. May 16, 2016 at 16:26
  • @Delia As for connecting via an SMTP forwarding service, that's more subjective as you need to balance the cost of doing vs, the threat of something like DDOS happening. It say if it's cost is low, and the implementation easy, than having a forwarding service doesn't hurt. May 16, 2016 at 16:29
  • @Andrie, DDOS should not be a concern. Just leaking the emails - as on somebody taking over my laptop remotely via the internet :) What if i convert the email to a base64 in which i replace certain letters based on a pattern :D? Would that help?
    – Delia
    May 16, 2016 at 17:54

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