Phishing attacks are widely used to distribute ransomware and keyloggers etc. Fully Windows is secure against redirection phishing attacks but the system is only as secure as using the latest versions update rollups etc.

Microsoft has been actively tracking a widespread credential phishing campaign using open redirector links. Attackers combine these links with social engineering baits that impersonate well-known productivity tools and services to lure users into clicking. 

Doing so leads to a series of redirections—including a CAPTCHA verification page that adds a sense of legitimacy and attempts to evade some automated analysis systems—before taking the user to a fake sign-in page. This ultimately leads to credential compromise, which opens the user and their organization to other attacks.

Email with personated corporations is common and the attack focus on the most successful corporations such as Apple. Spam claiming your Apple ID is locked out are common ruses.

Spammers use a hidden 1×1 pixel image to detect if the email account is valid or not. Spammers have been working overtime with new ideas to swindle the gullible.

The use of open redirects in email communications is common among organizations for various reasons. For example, sales and marketing campaigns use this feature to lead customers to a desired landing web page and track click rates and other metrics. However, attackers could abuse open redirects to link to a URL in a trusted domain and embed the eventual final malicious URL as a parameter. Such abuse may prevent users and security solutions from quickly recognizing possible malicious intent.

For instance, users trained to hover on links and inspect for malicious artifacts in emails may still see a domain they trust and thus click it. Likewise, traditional email gateway solutions may inadvertently allow emails from this campaign to pass through because their settings have been trained to recognize the primary URL without necessarily checking the malicious parameters hiding in plain sight.

This redirection phishing campaign is also notable for its use of a wide variety of domains for its sender infrastructure—another attempt to evade detection. These include free email domains from numerous country code top-level domains (ccTLDs), compromised legitimate domains, and attacker-owned domain generated algorithm (DGA) domains. As of this writing, we have observed at least 350 unique phishing domains used for this campaign. This not only shows the scale with which this attack is being conducted, but it also demonstrates how much the attackers are investing in it, indicating potentially significant payoffs.

Phishing continues to grow as a dominant attack vector with the goal of harvesting user credentials. Microsoft has blocked over 13 billion malicious and suspicious mails in the previous year, with more than 1 billion of those emails classified as URL-based phishing threats.

In this campaign, we noticed that the emails seemed to follow a general pattern that displayed all the email content in a box with a large button that led to credential harvesting pages when clicked. The subject lines for the emails varied depending on the tool they impersonated. In general, we saw that the subject lines contained the recipient’s domain and a timestamp as shown in the examples below:

  • [Recipient username] 1 New Notification
  • Report Status for [Recipient Domain Name] at [Date and Time]
  • Zoom Meeting for [Recipient Domain Name] at [Date and Time]
  • Status for [Recipient Domain Name] at [Date and Time]
  • Password Notification for [Recipient Domain Name] at [Date and Time]
  • [Recipient username] eNotification

Spam like this is pervasive. It is not just attacking Microsoft account, the miscreants are attacking everything in sight. Microsoft does not have a password expiration policy.

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