Spam email volume has reduced over the past couple of years following the takedown of key botnets – and individuals – behind some of the biggest spamming campaigns. It was starting to look like the super-spamming days of the early 2010s were a thing of the past. However, spam email volume has been increasing in recent months.
Necurs botnet activity has increased and last month the Tofsee botnet came back to life after years of dormancy. Both of these botnets had previously been used to send annoying but relatively harmless spam emails offering cheap pharmaceuticals and offers of beautiful Russian brides. However, the increase in activity is also coupled with the move to malicious email attachments containing malware and ransomware.
These and other botnets such as Helihos are also growing in size at alarming rates and spam email volume is soaring. Some reports suggest spam email volume has increased from around 200,000 spam emails per second to 450,000 emails per second over the past couple of months.
But what are these malicious email attachments, and how big is the risk?
97% of Malicious Spam Email Attachments Contain Locky Ransomware
Locky ransomware first appeared in February 2016. It has since become one of the biggest email threats. The ransomware is being sent in massive spam campaigns and increasingly sophisticated social engineering techniques are used to infect end users.
To put these email campaigns into some perspective, historically, the volume of spam email used to deliver malware, ransomware, and other email nasties stood at around 2% of the total spam email volume. By around April this year, two months after Locky first appeared on the scene, malicious spam emails containing the ransomware accounted for around 18% of total spam email volume.
The Quarterly Threat Report issued by ProofPoint earlier this month suggests the volume of spam email containing malicious attachments or links reached record levels in quarter 3, 2016. The vast majority of those emails contained Locky. According to the report, 97% of captured spam emails with malicious attachments were used to deliver Locky. That’s a 28% increase from Q2, and a 64% increase since Q1.
This discovery coincided with a drop in detection and a relatively quiet period for the past two weeks. However, Locky is back with a vengeance. On Monday this week, three new campaigns were detected, one of which was massive and involved 14 million messages in around half a day. 6 million of those messages were sent in a single hour!
The risk from Locky is considerable. Locky is capable of deleting Windows Shadow Files and encrypting a wide range of data, including data on portable storage devices and network drives. Resolving an attack can prove extremely costly. It is therefore essential to improve defenses to prevent attacks.
Ransomware and Malware Protection
Larger botnets and the move to malicious messages means organizations need to be prepared and take steps to ensure that these messages are effectively blocked.
Protecting your organization from email attacks is critical. It is therefore essential to employ a robust enterprise spam filtering solution. SpamTitan blocks 99.7% of spam email, preventing malicious email attachments and links from being delivered to your end users. This reduces reliance on training programs to educate end users on email threats.
Preventing ransomware infections requires a multi-layered approach. There is no silver bullet that will offer total protection against ransomware infections, but there are security products that can greatly reduce risk.
Protecting against exploit kits and malvertising requires a web filtering solution. By blocking websites known to contain malware or exploit kits, and carefully controlling the website content that can be accessed by employees, organizations can effectively protect against web-borne infections. WebTitan offers that protection and can be used to block malicious websites and reduce the risk from infections via malvertising.
Along with intrusion detection systems, firewalls, antivirus and anti-malware solutions, it is possible to defend against ransomware and malware attacks and keep your data secured.