November 3, 2021 By David Bisson 2 min read

Attackers are abusing the electronic agreement management company DocuSign to send phishing links and documents.

Inside the Phishing Attempt

First, a malicious actor registers a free account with DocuSign or compromises another user’s account. They then upload a file to the account.

Next, the attacker sends a DocuSign envelope to their target. The recipient, in turn, receives an email invitation from DocuSign. It prompts them to review and sign an electronic document by clicking on a hyperlinked ‘View Document’ button.

The email evades detection because it’s technically clean. DocuSign’s servers host the phishing link, thus allowing it to successfully land in a recipient’s inbox.

The process for signing a document is the same as with a legitimate file. The only difference is that clicking on the link redirects the recipient. They land on a phishing site designed to steal their login credentials for Dropbox, Microsoft and other services.

This technique works because PDFs, Word documents and other types of files in DocuSign retain their clickability up through the finished page. (DocuSign converts other types of uploaded document files into static PDFs to stop attacks.) A signer can then access the link and/or embedded files when they’re given the option to download the file — even if those resources are malicious.

In another method, an attacker could use a steganography attack. With this, they can spoof one of those supported file types to deliver a malware payload.

Recent DocuSign-Themed Campaigns

The attack described above stands out for its abuse of DocuSign’s platform. But there are plenty of attacks where phishers have faked the service to prey on unsuspecting users.

Back in August 2019, for instance, researchers uncovered a campaign targeting users across multiple verticals. The attack used stolen DocuSign branding. They sent victims to a phishing landing page designed to steal their Office 365 credentials.

DocuSign itself uncovered a phishing operation in April 2021. The attackers sent out fake envelopes from “@docusign.com.br” addresses. Unlike the attack described above, the emails did not originate from DocuSign.

In September, the service revealed a campaign where attackers hid malicious URLs in legitimate DocuSign envelopes. Those emails mainly came from the domain’s email[.]com and co[.]za. They used subject lines like ‘Bank Confirmation’ and ‘INVOICE.pdf’.

How to Defend Against Phishing Attacks Involving DocuSign

Users can protect themselves against phishing attacks spoofing DocuSign by not opening suspicious email attachments. In addition, consider hovering over embedded links to view the destination of those URLs. Access documents directly from DocuSign’s website. Organizations can build all of these considerations into their security awareness training programs.

At the same time, organizations might consider investing in an email security solution. This can help to scan incoming messages for malicious links and payloads. Such a tool could help to defend against attacks that seek to abuse services like DocuSign.

More from News

Poland spending $760 million on cybersecurity after attack

3 min read - Visitors to the Polish Press Agency (PAP) website on May 31 at 2 p.m. Polish time were met with an unusual message. Instead of the typical daily news, the state-run newspaper had supposedly published a story announcing that a partial mobilization, which means calling up specific people to serve in the armed forces, was ordered by Polish Prime Minister Donald Tusk beginning on July 1, 2024. Deputy Prime Minister Krzysztof Gawkowski refuted the claim on X (formerly Twitter). His post…

New ransomware over browser threat targets uploaded files

3 min read - We all have a mental checklist of things not to do while online: click on unknown links, use public networks and randomly download files sent over email. In the past, most ransomware was deployed on your network or computer when you downloaded a file that contained malware. But now it’s time to add a new item to our high-risk activity checklist: use caution when uploading files. What is ransomware over browsers? Researchers at Florida International University worked with Google to…

Exploring the 2024 Worldwide Managed Detection and Response Vendor Assessment

3 min read - Research firm IDC recently released its 2024 Worldwide Managed Detection and Response Vendor Assessment, which both highlights leaders in the market and examines the evolution of MDR as a critical component of IT security infrastructure. Here are the key takeaways. The current state of MDR According to the assessment, “the MDR market has evolved extensively over the past couple of years. This should be seen as a positive movement as MDR providers have had to evolve to meet the growing…

Topic updates

Get email updates and stay ahead of the latest threats to the security landscape, thought leadership and research.
Subscribe today