HashiCorp Vault is a popular open-source tool used for securely storing and accessing sensitive data such as passwords, API keys, certificates, and
encryption keys. It provides a centralized solution for managing secrets and helps organizations enforce security best practices.
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?
If a HashiCorp Vault token is compromised, it can have serious consequences for the security of the system and the sensitive data stored within the
Vault. Here are some potential consequences:
Compromise of sensitive personal data
This kind of service is often used to exchange information that could include personal information, chat logs, and other private data that users
have shared on the platform. This is called Personally Identifiable Information.
The leaked app key could provide a gateway for unauthorized individuals to access and misuse this data, compromising the privacy and safety of the
application users.
In many industries and locations, there are legal and compliance requirements to protect sensitive data. If this kind of sensitive personal data
gets leaked, companies face legal consequences, penalties, or violations of privacy laws.
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.
Breach of trust in non-repudiation and disruption of the audit trail
When such a secret is compromised, malicious actors might have the possibility to send malicious event objects, causing discrepancies in the audit
trail. This can make it difficult to trace and verify the sequence of events, impacting the ability to investigate and identify unauthorized or
fraudulent activity.
All in all, this can lead to problems in proving the validity of transactions or actions performed, potentially leading to disputes and legal
complications.
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.
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.
Analyze recent secret use
When available, analyze authentication logs to identify any unintended or malicious use of the secret since its disclosure date. Doing this will
allow determining if an attacker took advantage of the leaked secret and to what extent.
This operation should be part of a global incident response process.
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
import hvac
client = hvac.Client(url='https://vault.example.com', token='hvb.AAAAAQJyBEVF-vTWUrg0hcoIPuvKjjNxXXZ5MfsYVg2gJ0fGZpVi0IGTFfh4TqsoQIWaocNRXD1qzGXvhIHWJBM_rWU9YJY8sXOYVy_s1JAHasXJwGmZ_fBLJfSG6aCwQkCGwtAhYw') # Noncompliant
secret = client.secrets.kv.v2.read_secret_version(path='secret/myapp')
data = secret['data']
username = data.get('username')
password = data.get('password')
Compliant solution
import hvac
client = hvac.Client(url='https://vault.example.com', token=os.environ.get('VAULT_TOKEN'))
secret = client.secrets.kv.v2.read_secret_version(path='secret/myapp')
data = secret['data']
username = data.get('username')
password = data.get('password')
Resources
Documentation
Hashicorp API Documentation - Tokens
Hashicorp API Tutorial - Tokens
Hashicorp API Tutorial - Batch tokens
Standards
