In a concerning trend, threat actors are abusing DocuSign’s Envelopes API to create and distribute fake invoices that closely resemble legitimate documents from well-known brands like Norton and PayPal. By utilizing this legitimate electronic signature platform, attackers are able to bypass conventional email security measures, as the fraudulent invoices are sent from an authentic DocuSign domain, docusign.net. This deception aims to trick targets into electronically signing the documents, which can then be misused to authorize unauthorized payments outside of standard billing channels.
The Envelopes API is a critical component of DocuSign’s eSignature REST API, allowing users to automate document management processes. Unfortunately, malicious actors have been found exploiting paid DocuSign accounts to send these realistic fake invoices. By leveraging the platform’s templates and branding features, they can design documents that mimic the appearance of reputable organizations, making it challenging for victims to identify the fraud. Once created, they use the “Envelopes: create” function to distribute a high volume of these fraudulent invoices to numerous potential victims.
Security researchers from Wallarm have reported that these invoices maintain realistic pricing structures to enhance the legitimacy of the signing requests. If unsuspecting users sign these documents, attackers can subsequently utilize the signed copies to demand payments from the victims’ organizations or forward them to finance departments for unauthorized transactions. This approach allows criminals to effectively circumvent normal payment authorization processes, putting organizations at risk of significant financial loss.
Despite reports of this ongoing abuse, many users have expressed frustration on DocuSign’s community forums regarding the apparent lack of adequate response and reporting mechanisms for these phishing attempts. Although DocuSign has acknowledged the reports and stated their commitment to preventing misuse of their services, the challenge remains significant due to the difficulty in securing API endpoints against threats posed by attackers with legitimate commercial accounts. As this situation continues to evolve, it highlights the urgent need for enhanced security measures within widely-used platforms to protect against similar exploitation.
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