Know and understand the characteristics and effects of spam email and the methods which can be used to help prevent spam.
What is Spam Email?
Spam email (also called junk mail) is unsolicited, bulk electronic mail sent to large numbers of recipients, often for commercial or malicious purposes.
Characteristics of Spam Email
Sent in large volumes to many recipients.
Often uses deceptive subject lines to attract attention.
Contains promotional content, phishing links, or malicious attachments.
Usually originates from unknown or forged email addresses.
May use generic greetings such as “Dear Customer”.
Often includes poor grammar, spelling mistakes, or overly urgent language.
Effects of Spam Email
Individual Effects
Wasted time reading and deleting unwanted messages.
Risk of falling for phishing scams or downloading malware.
Loss of personal data if credentials are entered on fraudulent sites.
Organisational Effects
Reduced productivity due to employees handling spam.
Increased bandwidth and storage costs.
Potential security breaches leading to data loss or system compromise.
Damage to reputation if the organisation’s email address is spoofed.
Network Effects
Congestion of email servers and slower delivery of legitimate mail.
Higher load on firewalls and anti‑spam filters.
Propagation of malware across the network.
Methods to Prevent Spam Email
Prevention can be divided into technical controls and user practices.
Technical Controls
Control
How It Works
Typical Implementation
Spam Filters
Analyse content, sender reputation, and patterns to flag or quarantine suspicious messages.
Server‑side filters (e.g., Microsoft Exchange, Gmail) and client‑side filters (e.g., Outlook Junk Email).
Blacklists / Whitelists
Block known spammer IPs/domains (blacklist) or allow only approved senders (whitelist).
Integrated with mail servers or third‑party services such as Spamhaus.
Greylisting
Temporarily reject unknown senders; legitimate servers retry after a delay, spammers often do not.
Configured on mail transfer agents (MTAs).
DKIM, SPF, DMARC
Authenticate sender domain to prevent address spoofing.
DNS records and mail server settings.
Attachment Scanning
Detect and block executable or potentially harmful files.
Antivirus engines integrated with email gateways.
User Practices
Do not publish personal email addresses on public websites.
Use separate email accounts for online shopping, newsletters, and personal communication.
Never click on links or open attachments from unknown senders.
Report suspicious emails to the IT department or email provider.
Regularly update passwords and enable two‑factor authentication.
Mark unwanted messages as “spam” to improve filter learning.
Adopt safe user habits: cautious handling of unknown emails, use of separate addresses, reporting.
Suggested diagram: Flowchart showing how an incoming email passes through spam filters, authentication checks, and user actions before reaching the inbox.