The product attempts to initialize a resource but does not correctly do so, which might leave the resource in an unexpected, incorrect, or insecure state when it is accessed.
This can have security implications when the associated resource is expected to have certain properties or values. Examples include a variable that determines whether a user has been authenticated or not, or a register or fuse value that determines the security state of the product. For software, this weakness can frequently occur when implicit initialization is used, meaning the resource is not explicitly set to a specific value. For example, in C, memory is not necessarily cleared when it is allocated on the stack, and many scripting languages use a default empty, null value, or zero value when a variable is not explicitly initialized. For hardware, this weakness frequently appears with reset values and fuses. After a product reset, hardware may initialize registers incorrectly. During different phases of a product lifecycle, fuses may be set to incorrect values. Even if fuses are set to correct values, the lines to the fuse could be broken or there might be hardware on the fuse line that alters the fuse value to be incorrect.
Choose the safest-possible initialization for security-related resources.
Ensure that each resource (whether variable, memory buffer, register, etc.) is fully initialized.
Pay close attention to complex conditionals or reset sources that affect initialization, since some paths might not perform the initialization.
Ensure that the design and architecture clearly identify what the initialization should be, and that the initialization does not have security implications.
The technical impact can vary widely based on how the resource is used in the product, and whether its contents affect security decisions.
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)