Trend Micro has published a great study about spear-phishing email. It’s available here.
Although I would also like to know the overall numbers (i.e. amount of samples that were used during the research, to ensure the findings are really meaningful), there is good data in the paper that can feed into a well established SecOps practice. Some interesting pieces:
“Monitoring revealed that 94% of targeted emails use malicious file attachments while the rest use alternative methods like installing malware by luring victims to click malicious links and to download malicious files and using webmail exploits”
“Spear-phishing emails can have attachments of varying file types. We found that the most commonly used and shared file types in organizations (e.g., .XLS, .PDF, .DOC, .DOCX, and .HWP) accounted for 70% of the total number of spear-phishing email attachments during our monitoring.”
I’ve been spending a lot of time looking at numbers that affect the ability to look for potential compromises. For example, how many email messages an organization usually receives (of course it varies a lot according to size/business)? How many of those have attachments? How many of those attachments could be considered potentially dangerous? Is this information useful to help on narrowing the focus of detection/investigation practices?
I believe our industry has spent a lot of time working on detection systems without necessarily leveraging evidence based guidance about what to look for, where to look for. Reports like this one from TrendMicro are really useful to change that and help organizations to maximize the return of their SecOps resources.