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.
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.
Below are some real-world scenarios that illustrate some impacts of an attacker exploiting the secret.
An attacker can use this secret to spam users or lure them into links to a malicious domain controlled by the attacker.
Spam can cause users to be exposed to the following:
Once a user has been phished on a legitimate-seeming third-party website, an attacker can collect the user’s credentials, bypass multi-factor authentication (MFA), and take over the user’s account on the trusted website.
Due to this vulnerability, malware can be stored and spread, both to users of the service and to other potential targets.
A malware depends on
the attacker’s intentions, as the following examples show:
In the worst case, malware can cause the target systems to be completely compromised and allow attackers to infiltrate the systems.
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.
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.
Here is an example of a service account key file. In general it is in the form of a json file as demonstrated in the GCP docs.
{
"type": "service_account",
"project_id": "example-project",
"private_key_id": "2772b8e6f42dc67369b98f0b91694f7805b28844",
"private_key": "-----BEGIN PRIVATE KEY-----\nKBww9jggAgBEHBCBAASIMDsoCBAuAQINAgFAGSXQTkiAE0cEIkoQghJAqGavB/r3\n2W6raHa1Qrfj6pii5U2Ok53SxCyK3TxYc3Bfxq8orZeYC9LQ/I3tz7w4/BnT71AD\nfP1i8SWHsRMIicSuVFcRoYMA+A1eNSmdrujdBNWgedfuSyHbPnNY7s8BBUIoBN7I\n8gJG5DUUKAZfZDB2c/n7Yu0=\n-----END PRIVATE KEY-----\n",
"client_email": "example@example.iam.gserviceaccount.example.com",
"client_id": "492539091821492546176",
"auth_uri": "https://accounts.google.com/o/oauth2/auth",
"token_uri": "https://oauth2.googleapis.com/token",
"auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
"client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/example%40example.iam.gserviceaccount.example.com",
"universe_domain": "googleapis.com"
}
Always avoid committing service account key files to public systems. Use any *ignore file possible, such as .gitignore,
.dockerignore and equivalents for any other system accessing your local codebase.