A frequency analysis study of the words used in different types of spam has revealed the tactics used by spammers.
Research conducted by MessageLabs Intelligence into short URL spam split the data into four types: sales spam, phishing, malware and targeted attacks. In each case it classified the words used in the headers into a top 10 format.
The most common word in sales spam was 'Viagra', reflecting the popularity of pharmaceutical sales, which makes up around three quarters of all sales spam messages. 'Prices' was the second most common word, with 'special' and 'discount' also polling highly.
For both phishing and malware spam the top word was 'account', showing the financial targets commonly sought by the spammers. 'PayPal' was popular with phishers while malware writers favoured 'attached' or 'attachment', a favourite attack vector.
However, 'please' was the top word for targeted attacks, and it was also in the top five for phishers and malware spam.
"Politeness is a factor in successful spam," Paul Wood, MessageLabs Intelligence senior analyst, told V3.co.uk.
"When we look at malware the social engineering component is the most important. It's no use writing a sophisticated piece of malware if the social engineering isn't right"
Targeted spam attacks account for only around 0.02 per cent of all spam he said, but they are the most dangerous form since it can take weeks or months for a sample to turn up and a signature file developed by antivirus vendors.
"Even if you have up to date antivirus, no matter how good it is, such malware can be very difficult to find," he said.
"The most common method is for the software to be embedded in a document, so use maximum caution."
Overall the research found that on average one in every 74,000 spam emails was answered, with around 120bn spam messages sent every day.Return to security news headlines
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