Know and understand characteristics and effects of spam email including the methods which can be used to help prevent spam

10 Communication – Spam Email

Learning Objective

Know and understand the characteristics and effects of spam email, the email‑specific conventions that relate to it, and the methods (technical and user‑based) that can be used to prevent spam.

1. What is Spam Email?

Spam (or junk) email is unsolicited, bulk electronic mail sent to large numbers of recipients. It is usually commercial, but it can also be used for phishing, spreading malware or other malicious purposes.

2. Email‑specific Conventions (relevant to spam)

• CC and BCC – CC (carbon copy) shows all recipients; BCC (blind carbon copy) hides addresses. Spammers often use BCC to hide the full recipient list.
• Email groups / distribution lists – A single address that forwards to many users; can be abused for bulk sending.
• Attachment handling – Most organisations limit attachment size (e.g., 10 MB) and block certain file types (exe, bat, scr). Spam may contain malicious attachments that bypass these limits.
• Netiquette – Professional language, clear subject, appropriate greeting, and confidentiality. Spam typically ignores these rules (generic greetings, sensational subjects, urgent threats).
• Protocol overview – Email is transferred using SMTP (sending) and retrieved with POP3 or IMAP (receiving). Spam filters are placed in the SMTP chain, while authentication records (DKIM, SPF, DMARC) are checked via DNS before the message is delivered to the mailbox.

3. Characteristics of Spam Email

• Sent in large volumes to many recipients (often using BCC or groups).
• Deceptive, sensational or urgent subject lines designed to provoke an immediate click.
• Generic greetings such as “Dear Customer”, “Dear Sir/Madam” or no greeting at all.
• Poor grammar, spelling mistakes, and excessive use of capital letters or symbols.
• Originates from unknown, forged or spoofed email addresses (e.g., info@bank‑secure.com when the real domain is bank.com).
• Contains promotional material, phishing links, or attachments that may carry malware.

4. Effects of Spam Email

4.1 Individual Effects

• Wasted time reading, sorting and deleting unwanted messages.
• Increased risk of phishing – personal data or login credentials may be stolen.
• Potential infection by viruses, ransomware or spyware when malicious links/attachments are opened.
• Loss of confidence in email as a reliable communication tool.

4.2 Organisational Effects

• Reduced productivity – staff spend time handling spam instead of core tasks.
• Higher bandwidth usage and storage costs for mail servers.
• Additional load on firewalls, anti‑spam gateways and mail servers.
• Risk of security breaches, data loss or system compromise.
• Reputational damage if the organisation’s address is spoofed in spam messages.

4.3 Network Effects

• Congestion of email servers, slowing delivery of legitimate mail.
• Increased processing demand on SMTP relays and filtering appliances.
• Propagation of malware or phishing links across the internal network.

5. Legal and Ethical Considerations

Many countries treat unsolicited bulk email as a legal offence. The Cambridge syllabus expects students to know the key requirements of legislation such as the EU GDPR and the US CAN‑SPAM Act.

• Explicit consent must be obtained before sending marketing mail.
• The email must clearly identify the sender (name and valid physical address).
• An easy‑to‑use “unsubscribe” or opt‑out mechanism is mandatory.
• Four elements that make a commercial email lawful:

  1. Accurate “From” address (sender identification).
  2. Clear subject that does not mislead.
  3. Physical postal address of the sender.
  4. Unsubscribe link or instructions.

• Organisations that send or facilitate spam can face fines, civil action or criminal prosecution.

6. Methods to Prevent Spam Email

Prevention combines technical controls built into the email system with safe user practices.

6.1 Technical Controls (summary)

6.2 User Practices

1. Do not publish personal or work email addresses on public websites or forums.
2. Use separate email accounts for online shopping, newsletters and personal communication.
3. Never click links or open attachments from unknown or unexpected senders.
4. Report suspicious messages to the IT department or the email service provider.
5. Mark unwanted messages as “Spam” – this feedback helps filters improve.
6. Keep passwords strong, change them regularly and enable two‑factor authentication.
7. Follow netiquette: use a clear subject, appropriate greeting, and avoid sharing confidential information unless encrypted.

7. Summary Checklist

• Identify spam characteristics: bulk, deceptive subject, unknown/spoofed sender, generic greeting, poor language.
• Explain personal, organisational and network impacts of spam.
• Recall the five core technical controls: spam filter, blacklist/whitelist, greylisting, DKIM/SPF/DMARC, attachment scanning.
• Apply safe user habits: protect your address, separate accounts, avoid unknown links/attachments, report and mark spam, use strong passwords and 2FA.
• State the four mandatory elements of a lawful commercial email (sender ID, clear subject, physical address, unsubscribe option).
• Be aware of email conventions (CC/BCC, groups, attachment limits, netiquette) that affect how spam is sent and detected.