CWE-404: Improper Resource Shutdown or Release
Description
The product does not release or incorrectly releases a resource before it is made available for re-use.
When a resource is created or allocated, the developer is responsible for properly releasing the resource as well as accounting for all potential paths of expiration or invalidation, such as a set period of time or revocation.
- Abstraction
- ClassAn abstract weakness, independent of any specific language or technology.
- Likelihood of exploit
- Medium
- Status
- Draft
Common consequences
- AvailabilityOther
DoS: Resource Consumption (Other); Varies by Context
Most unreleased resource issues result in general software reliability problems, but if an attacker can intentionally trigger a resource leak, the attacker might be able to launch a denial of service attack by depleting the resource pool.
- Confidentiality
Read Application Data
When a resource containing sensitive information is not correctly shutdown, it may expose the sensitive data in a subsequent allocation.
Potential mitigations
- RequirementsLanguage Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- Implementation
It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.
- Implementation
Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
- Implementation
When releasing a complex object or structure, ensure that you properly dispose of all of its member components, not just the object itself.