Microsoft Warns of Sneaky Phishing Campaign

Microsoft is warning of an active phishing campaign that uses a combination of techniques to evade detection and trick users into giving up their credentials.

In a series of Tweets and updates on GitHub, Microsoft’s security team says the active phishing campaign uses a “craft combination” of legitimate-looking original sender email addresses, spoofed display sender address that contain the target usernames and domains, and display names that look like legitimate services.

Used together, these techniques help the emails slip through filters.

An active phishing campaign is using a crafty combination of legitimate-looking original sender email addresses, spoofed display sender addresses that contain the target usernames and domains, and display names that mimic legitimate services to try and slip through email filters.

— Microsoft Security Intelligence (@MsftSecIntel) July 30, 2021

Microsoft says the original sender addresses contain variations of the word “referral” and use various top-level domains, “including the domain com[.]com, popularly used by phishing campaigns for spoofing and typo-squatting.”

The attackers use a SharePoint lure in the display name and in the message, which Microsoft says poses as a file share request for Staff Reports, Bonuses, Pricebooks and other content, with a link that navigate to the phishing page.

Phishing remains one of the most widely used tactics of delivering malware or stealing credentials, and these attacks are increasing, according to new Ivanti research that found 80% of IT professionals are seeing an increasing of phishing attempts.

In this particular phishing attack, the malicious email contains two URLS that have malformed HTTP headers, with a primary phishing URL that is a Google storage resource that points to an AppSpot domain requiring users to sign in before serving another Google User Content domain with an Office 365 phishing page, Microsoft says.

Another URL is located within the notification settings and brings users to a compromised SharePoint site that attackers use to make the email seem more legitimate. Both URLs require sign-in to continue to the final page, Microsoft says.

”These plus a load of other detection evasion techniques make this campaign even sneakier than usual, but Microsoft Defender for Office 365 detects and blocks these emails.”