Microsoft 365 Vulnerabilities: New Threats from HTTP Client Tools

A recent study from cybersecurity vendor Proofpoint has thrown down the gauntlet regarding vulnerabilities in Microsoft 365 environments. The findings paint a startling picture: nearly 78% of Microsoft 365 tenants have faced targeted account takeover attempts, with attackers leveraging legitimate-sounding HTTP client tools, such as Axios, to slip past security defenses. Let’s dive into the details of these evolving threats and what they mean for Windows users and organizations alike.

An Evolving Battlefield in Cybersecurity​

Traditionally reserved for seamless communication between web servers and applications, HTTP client tools have been repurposed by threat actors to execute tactics like Adversary-in-the-Middle (AitM) attacks and brute force login attempts. The report underscores that these seemingly benign tools—when used with malicious intent—pose a severe risk to organizations, especially those relying heavily on Microsoft 365.

Key Findings:​

• Account Takeover Attempts: Proofpoint’s study reveals a whopping 78% of Microsoft 365 tenants encountered account takeover attempts, often through concentrated brute force strategies.
• Sophisticated Tools in Use: Campaigns using Axios—a popular promise-based HTTP client for both Node.js and browsers—have achieved notable success, compromising 43% of the targeted user accounts. Other tools, such as node-fetch and Go Resty, have also been documented, each with their own role and level of success in these attacks.
• Industry-Specific Risks: While campaigns have impacted sectors ranging from healthcare and finance to education and transportation, some approaches, like the node-fetch based operations, have especially targeted less-protected accounts in the education sector, facilitating spam campaigns or even resale of credentials.

How HTTP Client Tools Are Being Exploited​

Axios: More Than Just a Promise-Based Client​

Axios is celebrated in developer communities for its efficiency in handling asynchronous operations. However, in the hands of cybercriminals, its robust capabilities have been twisted into potent tools for:

• Bypassing Multifactor Authentication (MFA): There are alarming indications that attackers have not only managed to slip past MFA but have also intercepted MFA tokens, thereby reinforcing unauthorized access.
• Credential Theft via OAuth Exploitation: By hijacking OAuth integrations, attackers are creating persistent backdoors, allowing ongoing unauthorized access. This allows them to, for instance, create new mailbox rules that facilitate stealthy data exfiltration.

Node-fetch and Go Resty: Efficiency in Automation​

In contrast to Axios, node-fetch is known for its lightweight design, which makes it ideal for orchestrating large-scale brute force attacks. While its success rate might be lower—with only around 2% of organizations affected—it has still managed to target a significant volume of user accounts, particularly in the education sector. Meanwhile, Go Resty, which recently emerged in the threat landscape, boasted higher success rates during its brief campaign period, albeit ceasing operations shortly thereafter.

The Evolution of Attacks​

Historical data shows that the adaptation of HTTP client tools isn't entirely new. Back in 2018, an obscure version of the OkHttp client was used in a campaign focused on high-value Microsoft 365 targets, often leveraging credentials from major breaches like the LinkedIn leak of 2016. Fast forward to the past few years, and there’s an observable shift to include newer integrations, such as the python-request tool, with a recorded 7% uptick in account takeover attempts compared to previous periods.

Implications for Windows and Microsoft 365 Users​

For Windows users and enterprise administrators, these findings underscore the imperative need for a fortified cybersecurity posture. Here are a few takeaways and recommendations:

• Enhance MFA Mechanisms: Given reports of MFA token interception, consider refining your authentication methods, possibly integrating contextual or biometric factors that provide a stronger, multi-layer defense.
• Monitor Anomalous Activities: Utilize advanced logging tools and behavioural analytics to detect atypical access patterns, such as high-volume login attempts or unexplained modifications to mailbox rules.
• Regular Credential Audits: Frequent audits can help identify compromised accounts. Adopting a zero-trust strategy, where each login is rigorously verified, could significantly mitigate risks.
• Educate End Users: Maintain regular cybersecurity training sessions to help users recognize spear-phishing attempts and report suspicious activities. Familiarity with the threat landscape is one of the best defenses.

Broader Cybersecurity Trends and Future Outlook​

The reported surge in insecure HTTP client tool usage is a wakeup call in a rapidly digitalizing world. Cybercriminals are constantly refining their toolkits and weaving legitimate software into disingenuous operations. This means that as these tools evolve, so too must the defensive mechanisms. Enterprises must remain agile, employing both automated security solutions and user training to withstand these advanced threats.
What does this mean in the grand scheme of cybersecurity? It suggests a nuanced shift where attackers are not waiting for new vulnerabilities to emerge—they’re repurposing commonly used tools and exploiting operational habits. For Windows and Microsoft 365 users, keeping systems updated and staying informed about the latest security patches and advisories is more than just a good practice—it’s a necessity.

In Conclusion​

The recent Proofpoint findings provide a compelling look at how the cyber threat landscape is adapting. The misuse of HTTP client tools like Axios, node-fetch, and Go Resty signifies a broader, dynamic attack strategy aiming directly at everyday cloud services. As Windows and enterprise users brace for the next wave of cyberattacks, a comprehensive, multilayered security approach becomes imperative.
Have you noticed unusual activity within your Microsoft 365 environment? What steps are you taking to strengthen your authentication systems? Share your insights and experiences here at WindowsForum.com and join the discussion on how we can outmaneuver these ever-evolving digital threats.
Stay safe, stay secure, and keep those Windows updated!

---

Source: SecurityBrief Australia https://securitybrief.com.au/story/cyber-threats-to-microsoft-365-via-http-client-tools-surge