Secret leaks often occur when a sensitive piece of authentication data is stored with the source code of an application. Considering the source
code is intended to be deployed across multiple assets, including source code repositories or application hosting servers, the secrets might get
exposed to an unintended audience.
Why is this an issue?
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?
A reCaptcha secret key is a unique token that is used to verify the authenticity of reCaptcha requests made from an application to the reCaptcha
service. It is a key component in ensuring CAPTCHAs challenges issued by the application are properly solved and verified.
If a reCaptcha secret key leaks to an unintended audience, attackers with access to it will be able to forge CAPTCHA responses without solving
them. It will allow them to bypass the CAPTCHA challenge verification.
This can lead to an influx of spam submissions, automated attacks, or unauthorized access attempts depending on the feature the CAPTCHA mechanism
is intended to protect.
How to fix it
Revoke the secret
Revoke any leaked secrets and remove them from the application source code.
Before revoking the secret, ensure that no other applications or processes are using it. Other usages of the secret will also be impacted when the
secret is revoked.
Use a secret vault
A secret vault should be used to generate and store the new secret. This will ensure the secret’s security and prevent any further unexpected
disclosure.
Depending on the development platform and the leaked secret type, multiple solutions are currently available.
Code examples
Noncompliant code example
props.set("recaptcha_secret", "6LcaQa4mAAAAAFvhmzAd2hErGBSt4FC-BPzm4cNS")
Compliant solution
props.set("recaptcha_secret", System.getenv("RECAPTCHA_SECRET"))
Resources
Standards
Documentation
