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 cryptographic private key is a piece of sensitive information that is used in asymmetric cryptography. They are used in conjunction with public
keys to secure communications and authenticate digital signatures.
Private keys can be used to achieve two main cryptographic operations, encryption or digital signature. Those operations are the basis of multiple
higher-level security mechanisms such as:
- User authentication
- Servers authentication, for example in the X509 trust model
- E-mail encryption
Disclosing a cryptographic private key to an unintended audience can have severe security consequences. The exact impact will vary depending on the
role of the key and the assets it protects.
For example, if the key is used in conjunction with an X509 certificate to authenticate a web server as part of TLS communications, attackers will
be able to impersonate that server. This leads to Man-In-The-Middle-Attacks that would affect both the confidentiality and integrity of the
communications from clients to that server.
If the key was used as part of e-mail protocols, attackers might be able to send e-mails on behalf of the key owner or decrypt previously encrypted
emails. This might lead to sensitive information disclosure and reputation loss.
