CWE-773: Missing Reference to Active File Descriptor or Handle
Missing Reference to Active File Descriptor or Handle
Weakness ID: 773 (Weakness Variant)
Status: Incomplete
Description
Description Summary
The software does not properly maintain references to a file descriptor or handle, which prevents that file descriptor/handle from being reclaimed.
Extended Description
This can cause the software to consume all available file descriptors or handles, which can prevent other processes from performing critical file processing operations.
When allocating resources without limits, an attacker could prevent
all other processes from accessing the same type of resource.
Likelihood of Exploit
Medium to High
Potential Mitigations
Phase: Implementation
For system resources, consider using the getrlimit() function included
in the sys/resources library in order to determine how many resources
are currently allowed to be opened for the process.
When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users.
Phase: Operation
Use resource-limiting settings provided by the operating system or
environment. For example, setrlimit() can be used to set limits for
certain types of resources. However, this is not available on all
operating systems.
Ensure that your application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).
Vulnerability theory is largely about how behaviors and resources
interact. "Resource exhaustion" can be regarded as either a consequence or
an attack, depending on the perspective. This entry is an attempt to reflect
one of the underlying weaknesses that enable these attacks (or consequences)
to take place.
Description
