Are you old enough to remember when BCC in messages first came about?
Well, if you were born before November 21st 1977, you might stand a chance. This is the very day when RFC 733 was released, introducing the optional address feature “Blind Carbon” (later amended in August 1982 by RFC 822).
As the RFC states, the purpose of this feature is explained as follows:
This field contains the identity of additional recipients of the message. The contents of this field are not included in copies of the message sent to the primary and secondary recipients. Some systems may choose to include the text of the “Bcc” field only in the author(s)’s copy, while others may also include it in the text sent to all those indicated in the “Bcc” list.
Fast forward to the present, and many RFC’s later, the core purpose hasn’t changed. In fact, it’s remained unchanged since it involved real carbon paper dating back to the late 1940’s.
So, what’s the problem?
While Blind Carbon Copy offers an easy way to send emails to multiple recipients without revealing their addresses to each other, misunderstanding and misuse of BCC by users can present security risks. The UK Information Commissioner summarises the issues well in their guidance on the subject.
It’s also worth noting that the ICO cite that the misuse of BCC is a top ten cause of data breaches, with nearly 1000 incidents reported since 2019.
Here’s a quick run down as to why BCC should be used carefully (if at all) when communicating with others via email:
Breach of Privacy The biggest security risk posed by BCC is the potential for an accidental data breach.
If a BCC’d recipient ‘replies to all’ then their inclusion in the message thread will be revealed, almost certainly not the original intention.
Likewise, accidentally adding someone to the BCC group when personal or private information is being shared may also lead to a data breach.
Lack of Transparency BCC can be misused to hide recipients from important conversations or approvals. This lack of transparency can create confusion about who is involved in a decision or communication and hinder accountability.
Increased Risk of Phishing Attacks BCC has often led to some senders using generic greetings or avoiding personalisation in their emails, which are common tactics used in phishing scams. Recipients who are often blind copied into emails might be less cautious about clicking on links or attachments in such communications.
Accidental Omission There’s a chance of accidentally omitting a necessary recipient from the “To” or “CC” field when using BCC. This can lead to missed communication or delays in workflows.
Recommendations to mitigate BCC risks?
Use “BCC” with Caution There are of course a few good ‘use cases’ for using BCC. Yet, more often than not its use isn’t justified. In our experience, its most common use is to ‘cover ones backside’ should accountability become an issue.
And recipients know this too! How often have you heard someone say they haven’t read an email because they were copied in to it, let alone being blind copied?
As a rule of thumb, if everyone needs to be aware of a communication, then use the “To” or “CC” fields responsibly.
Turn BCC Off Alternatively, admins might consider turning off the BCC feature in order to drive better communication behaviours and potentially avoid users misusing the feature.
Use Separate Email Threads For complex communication involving multiple parties, we recommend using separate email threads with relevant recipients in each thread.
Consider Secure File Sharing Platforms When sharing sensitive data, consider using a secure file sharing platform with end to end encryption, access controls and auditing.
Use Group Lists or Distribution Lists Create group lists or distribution lists for frequently used recipient groups to avoid manual BCC entry and potential errors.
Final Thoughts
There is no simple solution to this dilemma. Understanding when and how to use BCC correctly lies at the heart of avoiding potential security issues. Office culture and doing things a certain way ‘because we’ve always done it that way’ is often behind most bad practices.
At DOQEX, we have clients that have chosen to remove the BCC feature completely, and we have clients who have put in place controls (including staff training) to help reduce the risk of email misuse and data loss. Either way, BCC should be an exception rather than the rule with most email communications.
Understanding the security risks of using BCC
Are you old enough to remember when BCC in messages first came about?
Well, if you were born before November 21st 1977, you might stand a chance. This is the very day when RFC 733 was released, introducing the optional address feature “Blind Carbon” (later amended in August 1982 by RFC 822).
As the RFC states, the purpose of this feature is explained as follows:
Fast forward to the present, and many RFC’s later, the core purpose hasn’t changed. In fact, it’s remained unchanged since it involved real carbon paper dating back to the late 1940’s.
So, what’s the problem?
While Blind Carbon Copy offers an easy way to send emails to multiple recipients without revealing their addresses to each other, misunderstanding and misuse of BCC by users can present security risks. The UK Information Commissioner summarises the issues well in their guidance on the subject.
It’s also worth noting that the ICO cite that the misuse of BCC is a top ten cause of data breaches, with nearly 1000 incidents reported since 2019.
Here’s a quick run down as to why BCC should be used carefully (if at all) when communicating with others via email:
Breach of Privacy
The biggest security risk posed by BCC is the potential for an accidental data breach.
If a BCC’d recipient ‘replies to all’ then their inclusion in the message thread will be revealed, almost certainly not the original intention.
Likewise, accidentally adding someone to the BCC group when personal or private information is being shared may also lead to a data breach.
Lack of Transparency
BCC can be misused to hide recipients from important conversations or approvals. This lack of transparency can create confusion about who is involved in a decision or communication and hinder accountability.
Increased Risk of Phishing Attacks
BCC has often led to some senders using generic greetings or avoiding personalisation in their emails, which are common tactics used in phishing scams. Recipients who are often blind copied into emails might be less cautious about clicking on links or attachments in such communications.
Accidental Omission
There’s a chance of accidentally omitting a necessary recipient from the “To” or “CC” field when using BCC. This can lead to missed communication or delays in workflows.
Recommendations to mitigate BCC risks?
Use “BCC” with Caution
There are of course a few good ‘use cases’ for using BCC. Yet, more often than not its use isn’t justified. In our experience, its most common use is to ‘cover ones backside’ should accountability become an issue.
And recipients know this too! How often have you heard someone say they haven’t read an email because they were copied in to it, let alone being blind copied?
As a rule of thumb, if everyone needs to be aware of a communication, then use the “To” or “CC” fields responsibly.
Turn BCC Off
Alternatively, admins might consider turning off the BCC feature in order to drive better communication behaviours and potentially avoid users misusing the feature.
Use Separate Email Threads
For complex communication involving multiple parties, we recommend using separate email threads with relevant recipients in each thread.
Consider Secure File Sharing Platforms
When sharing sensitive data, consider using a secure file sharing platform with end to end encryption, access controls and auditing.
Use Group Lists or Distribution Lists
Create group lists or distribution lists for frequently used recipient groups to avoid manual BCC entry and potential errors.
Final Thoughts
There is no simple solution to this dilemma. Understanding when and how to use BCC correctly lies at the heart of avoiding potential security issues. Office culture and doing things a certain way ‘because we’ve always done it that way’ is often behind most bad practices.
At DOQEX, we have clients that have chosen to remove the BCC feature completely, and we have clients who have put in place controls (including staff training) to help reduce the risk of email misuse and data loss. Either way, BCC should be an exception rather than the rule with most email communications.
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