Quote:According to the newest Threat Spotlight from Barracuda Networks, researchers analyzed emails and identified more than 300,000 unique malicious documents, representing 48% of all malicious files detected in the last 12 months. The frequency of document-based malware rose dramatically in the first quarter of 2019, with 59% of all malicious files coming from documents.
 
“For the past couple of years, script files were a very popular attack method. The percentage of these sort of files declined drastically, however, and was a significant source of the increase of documents as an infection method,” said Jonathan Tanner, senior security researcher at Barracuda Networks.
 
Although documents are good for targeted attacks, the document-based malware analyzed were all used in phishing campaigns. However, Tanner said they are used in targeted attacks as well since as a file type they are less suspicious and more common in clean emails than other file types that could contain malware.
 
“Documents are a natural evolution from script files, since the languages used are also the ones used for documents – namely VBScript and JavaScript (which was often just called VBScript). The same attacks could be converted to document-based ones with only slight modifications. The script authors had already become very adept at obfuscation techniques, so these could contribute greatly to document-based malware where scripting is already more common and thus deeper inspection of the script itself is required."