SSRF vulnerabilities occur when an API fetches a remote resource using a user-supplied Uniform Resource Identifier (URI) without adequate validation. This oversight allows attackers to manipulate the request, coercing the server to interact with unintended destinations. These attacks bypass traditional network controls like firewalls and VPNs, making them particularly insidious.
Broken Function Level Authorisation occurs when an attacker is able to access functions or data that they are not authorised to use. This happens due to inadequate enforcement of role-based access controls (RBAC) or a failure to properly segregate administrative and regular user functions. APIs often expose a variety of functions depending on the user’s role (e.g., regular user, administrator, manager, etc.). When these functions are not sufficiently protected or are poorly designed, attackers can bypass these restrictions to gain unauthorised access to sensitive information or perform malicious activities.
Unrestricted resource consumption occurs when an API allows users or clients to request resources without proper limits or controls. Every API request consumes a certain amount of resources such as CPU cycles, memory, network bandwidth, storage, and other external services (e.g. email, SMS, or biometric validation). If these resources are not regulated, an attacker can exploit the API to consume disproportionate resources, leading to a range of undesirable consequences including:
Denial of Service (DoS): An attacker may cause the API to become unresponsive by overwhelming it with an excessive number of requests, or by requesting resources that are computationally expensive, leading to system crashes or slowdowns.
Inflated Operational Costs: APIs that involve third-party services, such as SMS or email delivery, may incur costs for each request. Without proper restrictions, malicious actors can generate high volumes of such requests, leading to unexpected cost overruns.
Data Loss or Degradation: APIs that allow unregulated access to large amounts of data or storage can be abused, resulting in slow system performance, data corruption, or loss.
API3:2023 represents a nuanced security challenge where improper or absent authorisation checks allow attackers to access or manipulate sensitive properties of an object within an API. Unlike broader access control issues, this risk focuses specifically on granular authorisation, which determines the visibility or modifiability of individual object properties.
Insecure communication occurs when sensitive data is transmitted without adequate encryption or protective measures. This vulnerability enables attackers to intercept, alter, or steal data during transmission, exposing organisations to financial losses, reputational damage, and legal liabilities.