A spam filter is a filter in a software or web browser that protects the user from unwanted advertisements (spam) and phishing mails. Spam often appears in the form of spam mails in e-mail software or on blogs or forums in the comments. But also websites with unwanted advertisements can be detected and filtered by a spam filter.
Spam filters in e-mail programs
Spam filters are used primarily in e-mail programs. The filters can recognize spam mails on different programming and filter them out of the inbox. The filtered out e-mails are stored in the spam folder.
Different techniques of filtering can be:
â—Ź Blacklist – This filter list contains all undesirable characteristics, such as sender or certain keywords, based on which the spam filter categorizes the e-mail as spam, moves it to the spam folder or deletes it directly.
â—Ź IP address check – certain IP addresses (note: not sender addresses) are known for spam mails, the spam filter recognizes these and filters out the e-mails.
Of course, there are also some cases where the spam filter classifies emails incorrectly, for example, it does not sort out spam emails by mistake or it puts wanted emails into the spam folder by mistake.
However, thanks to the training mode in many spam filters, these can be further developed. After the user manually sorts out unwanted emails, the system becomes more and more accurate and sensitive to spam detection.
Methods used by spammers to spread spam
The improvement and adaptation of spam filters is also necessary because spammers are developing increasingly sophisticated methods of obtaining users’ e-mail addresses or data.
On the one hand, users on the Internet may be careless with their data and disclose it on websites. This is where spammers like to strike and then resell the e-mail addresses. But random generators can also be used to generate e-mail addresses that correspond to real addresses and are then used by spammers to send spam e-mails.
Programmed spam bots are used to scan websites for email addresses, or advertisements are automatically posted in blog or social media comments.
