The busiest day of the week for email spam is Tuesday and spammers concentrate on sending messages during working hours, Monday to Friday, according to a 2017 spam study conducted by IBM X-Force.
The study was conducted over a 6-month period from December 2016 to June 2017. The study analyzed more than 20 million spam messages and 27 billion webpages and images a day. The researchers also incorporated data provided by several anti-spam organizations, making the 2017 spam study one of the largest ever conducted.
The 2017 spam study showed the majority of spam emails – 83% – were sent to arrive in inboxes during office hours with Tuesday, Wednesday, and Thursday the spammiest days. Spam volume was much lower on Mondays and Fridays.
While spam is sent 24/7, the busiest times are between 1am and 4pm ET. If an email arrives at an inbox when a worker is at his/her desk, it is more likely to be opened. Spammers therefore concentrate their messages during office hours.
Malicious spam messages increase around the holidays and during tax season when email scams are rife. The increase in numbers of individuals heading online to shop for goods means rich pickings for spammers. Spam volume also increases during sporting events such as the Olympics, the Super Bowl and the Football World Cup, with sports-themed spam messages capitalizing on interest in the events.
Malicious messages aim to get email recipients to reveal their banking credentials, logins and passwords and install malware. The researchers found 44% of spam emails contained malicious code, and out of those emails, 85% were used to spread ransomware.
While the majority of spam messages are automated, the IBM researchers point out that spammers work at their campaigns. There is also considerable manual work required to control botnets and spam mailers. The process is not entirely automated. Considerable work is put into malicious messages that spread ransomware and malware, with these campaigns requiring the highest level of manual control. These campaigns also involve extensive planning to maximize the number of victims.
Spam is sent from countries all around the world, although the biggest percentage hails from India, which sends 30% of all spam emails. South America and China also send a high percentage of global spam. Only 7% of spam emails are sent from the United States and Canada.
Companies are getting better at filtering out spam emails and preventing the messages from reaching inboxes. Spam filtering technology has improved enormously in recent years, meaning fewer messages are being delivered; however, spam is still the main method of distributing malware and phishing scams are rife. Spammers are also getting much better at masking their malicious messages and they frequently change delivery vehicles develop new methods of hiding malicious code to avoid detection.
The researchers say spam email volume has increased fourfold over the past 12 months and malicious messages are now being increasingly targeted at organizations and individuals, rather than being sent randomly in huge spamming campaigns. Targeting allows the attackers to send carefully crafted campaigns which are more likely to result in the recipients taking the desired action.