In most cases, trust boundaries are violated when a secret is exposed in a source code repository or an uncontrolled deployment environment.
Unintended people who don’t need to know the secret might get access to it. They might then be able to use it to gain unwanted access to associated
services or resources.
The trust issue can be more or less severe depending on the people’s role and entitlement.
What is the potential impact?
The consequences vary greatly depending on the situation and the secret-exposed audience. Still, two main scenarios should be considered.
Financial loss
Financial losses can occur when a secret is used to access a paid third-party-provided service and is disclosed as part of the source code of
client applications. Having the secret, each user of the application will be able to use it without limit to use the third party service to their own
need, including in a way that was not expected.
This additional use of the secret will lead to added costs with the service provider.
Moreover, when rate or volume limiting is set up on the provider side, this additional use can prevent the regular operation of the affected
application. This might result in a partial denial of service for all the application’s users.
Application’s security downgrade
A downgrade can happen when the disclosed secret is used to protect security-sensitive assets or features of the application. Depending on the
affected asset or feature, the practical impact can range from a sensitive information leak to a complete takeover of the application, its hosting
server or another linked component.
For example, an application that would disclose a secret used to sign user authentication tokens would be at risk of user identity impersonation.
An attacker accessing the leaked secret could sign session tokens for arbitrary users and take over their privileges and entitlements.
