CWE-771: Missing Reference to Active Allocated Resource
Missing Reference to Active Allocated Resource
Weakness ID: 771 (Weakness Base)
Status: Incomplete
Description
Description Summary
The software does not properly maintain a reference to a
resource that has been allocated, which prevents the resource from being
reclaimed.
Extended Description
This does not necessarily apply in languages or frameworks that
automatically perform garbage collection, since the removal of all
references may act as a signal that the resource is ready to be
reclaimed.
Time of Introduction
Architecture and Design
Implementation
Common Consequences
Scope
Effect
Availability
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
Description
Implementation
For system resources, consider using the getrlimit() function included
in the sys/resources library in order to determine how many files are
currently allowed to be opened for the process.
(Good Code)
C
#include <sys/resource.h>
...
int return_value;
struct rlimit rlp;
...
return_value = getrlimit(RLIMIT_NOFILE, &rlp);
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.
Maintenance Notes
"Resource exhaustion" (CWE-400) is currently treated as a weakness,
although it is more like a category of weaknesses that all have the same
type of consequence. While this entry treats CWE-400 as a parent in view
1000, the relationship is probably more appropriately described as a
chain.
Description
