Researchers Detail AppSync Cross-Tenant Vulnerability in Amazon Web Services

Amazon Web Services has resolved a cross-tenant vulnerability in its platform that could be weaponized by an attacker to gain unauthorized access to resources.

“This attack abuses the AppSync service to assume roles in other AWS accounts, which allows an attacker to pivot into a victim organization and access resources in those accounts,” Datadog researcher Nick Frichette said in a report published last week.

AWS AppSync offers developers GraphQL APIs to retrieve or modify data from multiple data sources as well as automatically sync data between mobile and web applications and the cloud.

The service can also be used to integrate with other AWS services through specific roles designed to perform the necessary API calls with the required IAM permissions.

While AWS does have safeguards in place to prevent AppSync from assuming arbitrary roles by validating the role’s Amazon Resource Name, the problem stems from the fact that the check could be trivially bypassed by passing the “ServiceRoleArn” parameter in a lower case.

“This vulnerability in AWS AppSync allowed attackers to cross account boundaries and execute AWS API calls in victim accounts via IAM roles that trusted the AppSync service,” Frichette said.

Share this article on social media:

Subscribe to Our Newsletter!
Stay on top of cybersecurity risks, evolving threats and industry news.
This field is for validation purposes and should be left unchanged.

The Latest Cybersecurity News

From major cyberattacks, newly discovered critical vulnerabilities to recommended best practices, read it here first:

Tell us About your Needs
Get an Answer the Same Business Day

Got an urgent request? Call us at 1-877-805-7475 or Book a meeting.

What happens next:

  • We reach out to learn about your objectives
  • We work together to define your project’s scope
  • You get an all-inclusive, no engagement proposal
This field is for validation purposes and should be left unchanged.


Enter your Email Address

This field is for validation purposes and should be left unchanged.

* No free email provider (e.g:,, etc.)



Everything You Need to Know

Gain confidence in your future cybersecurity assessments by learning to effectively plan, scope and execute projects.
This site is registered on as a development site. Switch to a production site key to remove this banner.