Cyber Criminals Exploit DocuSign | Neuways – Technologist

In an alarming trend, cyber criminals have found new ways to exploit the DocuSign API to deliver fraudulent invoices that appear authentic. Unlike conventional phishing attacks that rely on suspicious-looking emails or malicious links, these schemes leverage legitimate DocuSign accounts and official templates, allowing cyber criminals to send fake invoices that users and security systems pass unnoticed.

The Challenge of Trusted Platform Exploitation

Traditional phishing attacks usually involve spoofed emails that mimic well-known brands, often luring victims into clicking harmful links or disclosing sensitive information. However, attackers now embed their tactics within legitimate platforms, making detection significantly more challenging.

Cyber criminals Exploit DocuSign API

Cyber criminals set up legitimate, paid DocuSign accounts in these incidents, enabling them to customise templates and utilise DocuSign’s APIs for large-scale operations. Using templates that mirror respected brands—such as Norton Antivirus—they craft invoices with accurate product pricing, realistic activation fees, or additional charges to appear authentic.

How the Scheme Works

The process is deceptively simple yet effective:

1. Creation of a DocuSign Account: Attackers set up a paid DocuSign account, granting them access to API capabilities and the ability to modify templates.
2. Use of Custom Templates and Branding: Attackers replicate brand-specific layouts, logos, and details, crafting invoices that appear official. Sometimes, they include legitimate-looking fees and pricing to further the illusion.
3. Submission of Fraudulent Invoices: These invoices may request signatures, allowing the attacker to use the signed document as a basis for unauthorised payment requests. Some documents may redirect finance teams to initiate wire transfers or payment orders.

Because these fraudulent invoices are sent directly through DocuSign’s platform, email filters are less likely to flag them as suspicious. The invoices look entirely legitimate with no overtly malicious links or attachments, heightening the risk for unsuspecting recipients.

The Rise in Malicious Activity and Increased Automation

Recent reports and discussions on DocuSign’s community forums suggest a rise in these malicious campaigns over the past several months. The breadth and persistence of these activities indicate that they are not isolated incidents; instead, attackers appear to be using automated methods to reach a broader range of victims. By exploiting DocuSign’s API-friendly infrastructure, they can scale their operations with minimal manual intervention, further enhancing their reach.

Recommendations for Protecting Your Organisation

In light of this evolving tactic used by cyber criminals to exploit DocuSign API, organisations need to enhance their security measures and educate employees on how to identify and respond to these threats. Here are some recommended actions:

For Businesses

Verify Sender Credentials: Always double-check the sender’s email address and associated accounts, particularly the “Reply-To” email field, which should match the official domain of the sender’s company. Watch for unusual sender addresses or unexpected formatting inconsistencies.

Implement Internal Approval Procedures: Establish strict protocols requiring multi-level approvals for financial transactions and payments. Involve multiple team members in the approval process for added security.

Provide Awareness Training: Educate employees about this emerging threat. Emphasise the importance of scepticism when handling requests, even from seemingly legitimate sources, and raise awareness of common signs of invoice fraud. Neuways offer Managed Security Awareness Training to help companies educate their employees.

Monitor for Anomalies: Regularly review invoices for unusual charges, fees, or unexpected purchase requests. Even minor inconsistencies can signal a potentially fraudulent request.

Follow Best Practices for Secure Platforms: Refer to guidance provided by platforms like DocuSign on identifying and reporting phishing attempts, and ensure employees know the steps to follow when a suspicious document is received.

For Service Providers to take note

Conduct Regular Threat Modelling

Understand the potential points of vulnerability within your platform or service by conducting threat modelling exercises. Identifying and addressing these areas is crucial for maintaining security.

Apply Intelligent Rate Limiting

Implement API rate limiting specifically for sensitive endpoints. By understanding typical API usage, rate limits can be tailored to prevent abuse without disrupting legitimate business activities.

Monitor for API Misuse

Use tools that can analyse API behaviour patterns, helping to detect and flag unusual activity that may indicate fraudulent usage.

What do businesses need to do from a Cyber Security perspective?

Exploiting trusted platforms like DocuSign highlights a new era in cyber criminal strategy, where attackers leverage legitimate services to execute fraud. By embedding malicious activities within authentic channels, they create an illusion of legitimacy, making these schemes harder to detect. Organisations must adapt to this evolving threat by bolstering their cyber security protocols, focusing on API security, and fostering a vigilant workforce prepared to recognise and counteract sophisticated attacks.