Can the recipient tell if someone is BCC'd on an email?

Most email programs allow you to send messages to multiple recipients at once. You can add a bunch of people to the "To" field and send it off. Or you can place a few in the "To" field and CC the others. Alternatively, you may BCC some or all of them.

BCC is arguably the most complex option because not everyone has access to the same set of recipients. It carries the greatest potential for mistakes. So, when should you CC and when should you BCC?

First, it's important to understand what CC and BCC mean. CC stands for carbon copy, while BCC stands for blind carbon copy. Carbon copies were common before the internet era. To make a copy of a document, carbon paper was placed between two sheets of paper. The ink or type would transfer onto the second sheet, giving you two identical copies.

What does CC mean in email? Nowadays, an email CC is used to send a copy of a message to someone besides the primary recipient – it's an easy way to keep other interested parties informed. Notably, everyone can see each other's email addresses when using CC.

BCC functions similarly to CC, except that the direct recipient (in the 'To' field) is unaware that anyone else has received a copy of the email. For example, if you email a colleague about being late to the office and BCC your boss to show your diligence, your colleague would have no idea that your boss is also in the loop.

Does that seem a bit sneaky or secretive, almost like telling on a sibling? It should. BCC could be called the 'backstabbing carbon copy,' as its use often involves etiquette issues and the potential for negative consequences. If you're deliberately hiding the fact that there are BCC recipients, it's worth considering your reasons for doing so.

BCC is a notorious office minefield, especially if the BCC'd person accidentally hits 'Reply All.' Their reply will be sent not just to you, but also to the main recipient. Oops. This kind of unintentional revelation has caused many tense office situations. The lesson? If you're BCC'd, be extra cautious and never use 'Reply All.'

Despite the challenges, there are strong reasons to use BCC. For instance, if you're managing multiple contract or freelance workers who don't interact with each other, and you need to inform them all about policy updates without sending separate emails, BCC allows you to add their addresses all at once.

This is not only convenient for you – it also ensures the privacy of your freelancers, who likely don't want their personal email addresses shared with people they don't know.

Alternatively, if your company needs to notify a large number of customers about a significant matter, using BCC is essential. Without it, you could end up exposing hundreds or thousands of private email addresses, which would be a serious breach of trust.

Can a BCC Recipient Be Exposed?

But what if there was a way for recipients to uncover who was BCC'd on an email, without the sender knowing? This could not only create awkward situations but also lead to significant privacy violations for those who prefer to keep their email addresses hidden.

"Generally, recipients can't see if someone has been blind-copied on a message," says Sherrod DeGrippo, senior director of threat research and detection for Proofpoint Email. "Servers that receive messages are designed to strip out 'BCC' information before they pass the message on to the recipient. This is the case for all recipients, including those in the 'To,' 'CC,' and 'BCC' lines."

But as with all things digital, that's not the end of the story. Typically, it's user error that causes BCC privacy breaches.

"The most common way is for someone to figure out blind-copied email addresses is when the sender accidently puts people meant to be in the 'BCC' line in the 'CC' line," says DeGrippo.

However, she notes that threat actors – hackers – have found ways to attack the privacy of BCC. One would be to access the target's inbox in one way or another, and then simply look in the Sent items to find out who received a BCC message. Or, if your device is infected with data-stealing malware, an attacker could access messages in the Sent folder.

"Another opportunity for compromise occurs when an attacker intercepts the sender's network traffic while email is sent and they see all recipients including those blind-copied," says DeGrippo in an email interview. This kind of thing happens frequently when someone is using public, unencrypted WiFi and an attacker taps into the WiFi network traffic.

"Finally, if an attacker gains access to the email servers of the sender or any of the recipients (including those in the 'To,' 'CC,' and 'BCC' fields) or intercepts the network traffic between these servers, they could potentially view all the recipients," explains DeGrippo.

In other words, BCC is far from foolproof. So, if you're a spy dealing with sensitive state information, consider this your warning.

Using BCC Wisely

To safeguard yourself when using BCC, there are several steps you can take. The first and simplest is to double-check your recipients before hitting send, ensuring you're using BCC rather than CC.

Regularly updating your security software and antivirus programs is also crucial. This will help protect your device from current threats.

"Make sure to protect your email accounts with strong passwords and multi-factor authentication whenever possible," advises DeGrippo. "It's crucial to avoid using unsecured, public WiFi networks. If you have to use them, ensure you connect through a virtual private network (VPN) that will encrypt and secure your data."

Now that you have a better understanding of BCC, you can safeguard yourself and your colleagues, preventing any potential email disasters.