The Microsoft OneNote application is being abused by threat actors to bypass phishing detection rules and compromise victims.

A large proportion of the malware delivered through OneNote has been identified as AsyncRat, Gozi and CryptOne.

It appears that once again Microsoft applications are being incorporated into phishing attacks, this time OneNote is the application of choice for those seeking to infect victims with malware in lieu of Microsoft VBA macros.

Since OneNote is included in the MS Office package, it is installed on all Windows devices by default regardless of if it being used or not by the potential victim.

The same social engineering techniques such as brand impersonation are still employed to help convince the user of the email’s legitimacy.

Opening the OneNote attached will not execute any scripts but will contain an embedded attachment/script disguised to look as legitimate and appropriate as possible, which when clicked will execute and begin the delivery of malware which has largely been in the form of remote access tools and information stealers designed to exfiltrate a victim’s financial information.

Organisationg that take a proactive approach to combat social engineering attacks by providing training to their staff should ensure that training is up to date to include these new changes in tactics, techniques, and procedures (TTPs).

It is much less effective for a threat actor to send an MS Word or Excel attachment these days, as such, educating personnel to be aware of phishing with OneNote or compressed files containing unusual attachments should be included.

Reporting

Report all Fraud and Cybercrime to Action Fraud by calling 0300 123 2040 or online. Forward suspicious emails to report@phishing.gov.uk. Report SMS scams by forwarding the original message to 7726 (spells SPAM on the keypad).