How does JNDI injection work?

JNDI (Java Naming and Directory Interface) injection is a common attack technique that involves exploiting the use of JNDI services in an application to inject malicious objects or execute malicious code. The way JNDI injection works is as follows:

1. The attacker triggers JNDI service calls in the application by inputting malicious data, such as a malicious URL or input field.
2. The application tries to find an object in the configured JNDI service based on the provided JNDI name.
3. The attacker creates a malicious object and registers it with a local or remote JNDI service, using the same JNDI name as a legitimate object.
4. When the application searches for an object in the JNDI service, malicious objects are returned and used by the application.
5. Malicious code executed by an attacker could result in security vulnerabilities in applications, such as remote code execution and information leakage.

The principle of JNDI injection is to deceive the application by forging or replacing legitimate JNDI objects, causing it to use malicious objects. This attack technique exploits the application’s trust in JNDI services, allowing attackers to execute unauthorized operations by manipulating the JNDI context. To prevent JNDI injection attacks, application developers should handle JNDI names constructed from user input with caution and restrict the permissions of JNDI lookups. Additionally, timely updating and maintaining secure configurations of JNDI services are important defensive measures.