At its core, SSRF arises when an attacker can manipulate a server to send HTTP requests to arbitrary destinations, often bypassing firewalls, access controls, and other security measures. The vulnerability stems from improper validation of user-supplied URLs or inputs that dictate server-side request behaviour.
CWE-863: Incorrect Authorisation occurs when an application fails to enforce correct authorisation measures, allowing unauthorised users or processes to access resources, perform operations, or retrieve data that should be off-limits. It is sometimes conflated with authentication flaws, but the essence of CWE-863 lies in improper or missing checks that would otherwise confirm if a user has the necessary permissions to perform a specific action.
From a technical standpoint, one might imagine an application employing robust identity verification (authentication) only to overlook critical checks about what a user is allowed to do once logged in (authorisation). This oversight can be the gateway to data leaks, privilege escalation, or even sabotage of core business processes.
CWE-200 refers to a software flaw where sensitive information—such as personal data, proprietary business details, or system configurations—is unintentionally exposed to individuals or entities without proper authorisation. This weakness typically results from poor implementation of access controls, inadequate data masking, or flawed logic in data-handling processes.
Deserialisation refers to the process of converting serialised data (a compact format of an object or data structure) back into its original form. While this operation is indispensable in modern software, it becomes a vulnerability when the deserialised data originates from an untrusted source.
When untrusted data is deserialised without validation, attackers can exploit the process to execute arbitrary code, manipulate application logic, or inject malicious payloads. CWE-502 encapsulates this weakness, highlighting its potential to compromise data integrity, confidentiality, and availability.
Improper Privilege Management, as classified under CWE-269, occurs when a software application improperly manages or enforces access control policies, allowing unauthorised users to perform restricted actions. This weakness can lead to severe consequences, such as data breaches, privilege escalation, and compromise of system integrity.