AppRiver observed more than 23 million emails delivering ransomware in only 24 hours, according to an Aug. 28 company blog post.
The Gulf Breeze, Fla.-based cybersecurity company, which focuses on email and web protection services, said it identified a "large spike in malware traffic" Aug. 28. The emails utilized the following subject lines: "please print," "documents," "photo," "images," "scans" and "pictures."
Each email included a ZIP attachment containing a file that initiated a sequence of events, eventually downloading the latest Locky ransomware. Locky was one of the most frequently detected ransomware variants in 2016, although it had waned in prevalence in recent months.
After the Locky ransomware encrypts a target's files, it leaves decryption instructions demanding 0.5 in bitcoins, or roughly $2,150.
Click here to view the blog post.