HubPhish Campaign: How Cybercriminals Exploit Trusted Platforms like HubSpot

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If you thought phishing was stuck sending shady attachments through email, think again. Today’s cybercriminals are crafting smarter, more insidious attacks, like the recent HubPhish campaign. This targeted operation leveraged none other than HubSpot, a widely trusted marketing and sales platform, to dupe organizations in Europe’s automotive, chemical, and industrial compound sectors—with frightful success. According to a report by Palo Alto Networks Unit 42, this attack led to the exfiltration of more than 20,000 Microsoft Azure account credentials. Let’s break this down to understand how it happened, what it means, and how Windows users can protect themselves against this and similar threats.

Anatomy of the HubPhish Campaign​

It all started with emails meant to blend perfectly into your busy workday. Cybercriminals turned to a tried-and-true tactic to initiate their attack: spoofed DocuSign emails (because hey, digital paperwork is a universally tormenting necessity). These emails included malicious links that seemed innocently related to DocuSign’s document validation process.
But the pièce de résistance? Instead of linking directly to suspicious domains or malware, these emails redirected victims to HubSpot’s Free Form builder. There, unsuspecting users were guided to login forms replicating Microsoft’s Outlook Web App (OWA) in astounding detail. It was a perfect trap designed to steal login credentials with a single thoughtless keystroke.
The criminals’ plan didn’t stop with mere data theft. After collecting Azure credentials, they launched attacks directly onto victims' cloud environments, using those accounts for further lateral movement. If this feels like a masterclass in patient, meticulous cybercrime, that's because it is.

Why HubSpot Was a Prime Tool in This Campaign​

The use of HubSpot’s tools highlights how attackers now embrace platforms designed to legitimize email communication. HubSpot is a trusted platform in the marketing automation world, known for keeping emails polished and professional-appearing. By rerouting malicious intent through HubSpot’s infrastructure—without compromising HubSpot itself—attackers effectively sidestepped many built-in email security measures. Filters get tripped up when an email links to a reputable source like HubSpot. That’s akin to sneaking past a bouncer by wearing a staff uniform.
Big takeaway? Trustworthy tools can be weaponized in skilled hands.
HubSpot’s infrastructure itself remained untouched, according to Palo Alto's investigation, meaning the attackers found clever ways to exploit its external reputation. As users, this warns us never to drop our guard, even when a platform we trust is involved.

From Theft to Lateral Cloud Exploitation​

Stealing your Azure credentials is bad enough—but the HubPhish attackers weren’t satisfied with just breaching the front door. They used these stolen accounts to deploy lateral movement attacks. Let’s unpack this a bit.
Think of lateral movement as cyber crooks breaking into your house and not just stealing from the foyer—they spread out, rummaging through every room, checking every drawer, and potentially stealing spare keys (i.e., more credentials) for your other properties in the process. Here, the entries weren’t living-room desks but endpoints connected to Microsoft Azure environments. These cloud-based infrastructures are goldmines for personal, corporate, and even classified data.
What makes lateral movement attacks so hard to detect is that each step looks like legitimate activity to the untrained eye. Attackers use stolen credentials to mimic regular employees, accessing resources and avoiding detection until it’s far too late.

Connecting the Dots: The Role of Cloud Platforms in Modern Threats​

This isn’t the first time attackers have gone fishing in the cloud—and it won’t be the last. Earlier phishing campaigns targeted other Microsoft environments (like SharePoint) and even spread XLoader malware, a nasty piece of work designed to steal passwords and other sensitive credentials. When it comes to cloud security, complacency is the number one enemy.

Why Microsoft Azure?​

Microsoft’s massive share in the enterprise cloud market makes it an obvious target. Azure connects critical business systems, and once inside, attackers often find unguarded or "barely-secured" treasure troves. The stolen credentials can be monetized quickly or weaponized for further attacks, like ransomware deployment or network extortion.

Echoes of Other Attacks: Crossing Platforms​

Interestingly, reports indicate parallel phishing trends abusing other trusted tools like Google Calendar (yes, even innocent-looking calendar invites can be weaponized). Safe to say, phishing campaigns are growing in sophistication, exploiting not only user naivety but also blind trust in reputable services.

What This Means for You: Lessons for Windows Users​

Let’s cut to the chase. If you’re a Windows user—be it on a personal machine or managing your company’s IT—you need to take advanced precautionary steps. Attacks like HubPhish demand more than a “vanilla” security posture.

Top 5 Security Steps to Protect Your Accounts and Systems​

  • Enable Multi-Factor Authentication (MFA) Everywhere
    Yes, this is step zero for a reason. Even if attackers have your credentials, they're in for a rude awakening when MFA blocks their way. For Windows users, setting up MFA for Microsoft Office 365 or Azure is a no-brainer.
  • Watch Out for Email Spoofing Tactics
    While Microsoft and other email providers block billions of phishing emails daily, a cleverly designed lure might still slip through. Verify email senders manually before responding or clicking links.
  • Use a Cloud Access Security Broker (CASB)
    These tools extend your endpoint protection efforts into your cloud environment. Think of it as placing surveillance cameras around your house and not just locking the front door. Windows Defender integrates with Azure Sentinel for native security coverage.
  • Audit Permissions on Existing Cloud Infrastructure
    Azure and OneDrive users too often skip stringent permission reviews. Over-permissioned accounts are attacker magnets during lateral movement attempts.
  • Educate Everyone in Your Network
    While IT teams focus on firewalls and malware scanning, employees are often the weakest link. Don’t forget to invest time teaching staff to identify phishing campaigns, especially when they involve high-trust platforms like DocuSign or Google Calendar.

The Bigger Picture: Adapt, or Risk Disaster​

The HubPhish campaign is yet another reminder that cloud security is not optional—it’s mandatory. Tools meant to simplify work processes, like HubSpot and Office 365, have proven particularly enticing for attackers looking to exploit complacency. In a world where cybercrime adapts faster than many organizations can respond, staying proactive has never been more important.
As Microsoft continues to expand its cloud services, expect to see even greater emphasis on Azure security features such as Conditional Access Policies and Zero Trust Architecture. Windows users should take note of these trends and consider how features like cloud app monitoring or improved endpoint security via Microsoft Defender Antivirus might provide an additional layer of protection.

Sound Off: What’s Your Take?​

Are these attacks a sign that cloud reliance has made businesses vulnerable in unexpected ways? What measures are you taking within your personal or professional network to avoid being an easy target? Jump into the comments and share your thoughts!
And, as always, if you need more tips or tutorials on Microsoft security features, you know where to find us—right here on WindowsForum.com!

Source: SC Media European firms subjected to HubSpot-exploiting phishing