CWE-404: Improper Resource Shutdown or Release Weakness ID: 404 Vulnerability Mapping:
ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. |
 Description The product does not release or incorrectly releases a resource before it is made available for re-use. Extended Description 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. Common Consequences  This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.| Scope | Impact | Likelihood |
|---|
Availability
Other
| Technical Impact: 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
| Technical Impact: 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
Phase: Requirements Strategy: Language 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. |
Phase: 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. |
Phase: Implementation Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[]. |
Phase: Implementation When releasing a complex object or structure, ensure that you properly dispose of all of its member components, not just the object itself. |
Relationships This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore. Relevant to the view "Research Concepts" (CWE-1000) | Nature | Type | ID | Name |
|---|
| ChildOf |  Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things. | 664 | Improper Control of a Resource Through its Lifetime | | ParentOf |  Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 299 | Improper Check for Certificate Revocation | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 459 | Incomplete Cleanup | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 763 | Release of Invalid Pointer or Reference | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 772 | Missing Release of Resource after Effective Lifetime | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 1266 | Improper Scrubbing of Sensitive Data from Decommissioned Device | | PeerOf |  Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. | 405 | Asymmetric Resource Consumption (Amplification) | | PeerOf |  Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 239 | Failure to Handle Incomplete Element | | CanPrecede | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 619 | Dangling Database Cursor ('Cursor Injection') |
 Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003) | Nature | Type | ID | Name |
|---|
| MemberOf |  View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). | 1003 | Weaknesses for Simplified Mapping of Published Vulnerabilities | | ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 401 | Missing Release of Memory after Effective Lifetime | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 459 | Incomplete Cleanup | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 763 | Release of Invalid Pointer or Reference | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 772 | Missing Release of Resource after Effective Lifetime |
Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305) | Nature | Type | ID | Name |
|---|
| ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 401 | Missing Release of Memory after Effective Lifetime | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 772 | Missing Release of Resource after Effective Lifetime | | ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 775 | Missing Release of File Descriptor or Handle after Effective Lifetime |
Relevant to the view "CISQ Data Protection Measures" (CWE-1340) | Nature | Type | ID | Name |
|---|
| ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 761 | Free of Pointer not at Start of Buffer | | ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 762 | Mismatched Memory Management Routines | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 763 | Release of Invalid Pointer or Reference | | ParentOf | Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 772 | Missing Release of Resource after Effective Lifetime | | ParentOf | Variant - a weakness
that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. | 775 | Missing Release of File Descriptor or Handle after Effective Lifetime |
Modes Of Introduction The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase. Likelihood Of Exploit Demonstrative Examples Example 1 The following method never closes the new file handle. Given enough time, the Finalize() method for BufferReader should eventually call Close(), but there is no guarantee as to how long this action will take. In fact, there is no guarantee that Finalize() will ever be invoked. In a busy environment, the Operating System could use up all of the available file handles before the Close() function is called. (bad code) Example Language: Java
private void processFile(string fName) { BufferReader fil = new BufferReader(new FileReader(fName)); String line; while ((line = fil.ReadLine()) != null) { processLine(line); } } The good code example simply adds an explicit call to the Close() function when the system is done using the file. Within a simple example such as this the problem is easy to see and fix. In a real system, the problem may be considerably more obscure. (good code) Example Language: Java
private void processFile(string fName) { BufferReader fil = new BufferReader(new FileReader(fName)); String line; while ((line = fil.ReadLine()) != null) { processLine(line); } fil.Close(); } Example 2 This code attempts to open a connection to a database and catches any exceptions that may occur. (bad code) Example Language: Java
try { Connection con = DriverManager.getConnection(some_connection_string); } catch ( Exception e ) { log( e ); } If an exception occurs after establishing the database connection and before the same connection closes, the pool of database connections may become exhausted. If the number of available connections is exceeded, other users cannot access this resource, effectively denying access to the application. Example 3 Under normal conditions the following C# code executes a database query, processes the results returned by the database, and closes the allocated SqlConnection object. But if an exception occurs while executing the SQL or processing the results, the SqlConnection object is not closed. If this happens often enough, the database will run out of available cursors and not be able to execute any more SQL queries. (bad code) Example Language: C#
...
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(queryString);
cmd.Connection = conn;
conn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
HarvestResults(rdr);
conn.Connection.Close();
...
Example 4 The following C function does not close the file handle it opens if an error occurs. If the process is long-lived, the process can run out of file handles. (bad code) Example Language: C
int decodeFile(char* fName) {
char buf[BUF_SZ]; FILE* f = fopen(fName, "r"); if (!f) { printf("cannot open %s\n", fName);
return DECODE_FAIL; } else {
while (fgets(buf, BUF_SZ, f)) { if (!checkChecksum(buf)) { return DECODE_FAIL; } else { decodeBlock(buf); } } } fclose(f); return DECODE_SUCCESS; } Example 5 In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource. (bad code) Example Language: C++
class A { void foo(); }; void A::foo(){ int *ptr;
ptr = (int*)malloc(sizeof(int));
delete ptr; } Example 6 In this example, the program calls the delete[] function on non-heap memory. (bad code) Example Language: C++
class A{ void foo(bool); }; void A::foo(bool heap) { int localArray[2] = { 11,22 }; int *p = localArray; if (heap){ p = new int[2]; } delete[] p; } Observed Examples | Reference | Description |
|---|
| Does not shut down named pipe connections if malformed data is sent. |
| Sockets not properly closed when attacker repeatedly connects and disconnects from server. |
| Chain: Return values of file/socket operations are not checked ( CWE-252), allowing resultant consumption of file descriptors ( CWE-772). |
Weakness Ordinalities | Ordinality | Description |
|---|
Primary | (where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) Improper release or shutdown of resources can be primary to resource exhaustion, performance, and information confidentiality problems to name a few. |
Resultant | (where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) Improper release or shutdown of resources can be resultant from improper error handling or insufficient resource tracking. |
Detection Methods
Automated Dynamic Analysis This weakness can be detected using dynamic tools and techniques that interact with the software using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results. Resource clean up errors might be detected with a stress-test by calling the software simultaneously from a large number of threads or processes, and look for evidence of any unexpected behavior. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results. |
Manual Dynamic Analysis Identify error conditions that are not likely to occur during normal usage and trigger them. For example, run the product under low memory conditions, run with insufficient privileges or permissions, interrupt a transaction before it is completed, or disable connectivity to basic network services such as DNS. Monitor the software for any unexpected behavior. If you trigger an unhandled exception or similar error that was discovered and handled by the application's environment, it may still indicate unexpected conditions that were not handled by the application itself. |
Automated Static Analysis 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.) |
Memberships This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources. Vulnerability Mapping Notes Usage: ALLOWED-WITH-REVIEW (this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review) | Reason: Abstraction | Rationale: This CWE entry is a Class and might have Base-level children that would be more appropriate | Comments: Examine children of this entry to see if there is a better fit |
Notes Relationship Overlaps memory leaks, asymmetric resource consumption, malformed input errors. Taxonomy Mappings | Mapped Taxonomy Name | Node ID | Fit | Mapped Node Name |
|---|
| PLOVER | | | Improper resource shutdown or release |
| 7 Pernicious Kingdoms | | | Unreleased Resource |
| OWASP Top Ten 2004 | A9 | CWE More Specific | Denial of Service |
| CERT C Secure Coding | FIO42-C | CWE More Abstract | Close files when they are no longer needed |
| CERT C Secure Coding | MEM31-C | CWE More Abstract | Free dynamically allocated memory when no longer needed |
| The CERT Oracle Secure Coding Standard for Java (2011) | FIO04-J | | Release resources when they are no longer needed |
| Software Fault Patterns | SFP14 | | Failure to release resource |
References
[REF-44] Michael Howard, David LeBlanc
and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.
|
Content History | Submissions |
|---|
| Submission Date | Submitter | Organization |
|---|
2006-07-19
(CWE Draft 3, 2006-07-19) | PLOVER | | | | Modifications |
|---|
| Modification Date | Modifier | Organization |
|---|
| 2008-07-01 | Eric Dalci | Cigital | | updated Time_of_Introduction | | 2008-08-15 | | Veracode | | Suggested OWASP Top Ten 2004 mapping | | 2008-09-08 | CWE Content Team | MITRE | | updated Description, Relationships, Other_Notes, Taxonomy_Mappings | | 2008-10-14 | CWE Content Team | MITRE | | updated Relationships | | 2008-11-24 | CWE Content Team | MITRE | | updated Relationships, Taxonomy_Mappings | | 2009-01-12 | CWE Content Team | MITRE | | updated Common_Consequences, Likelihood_of_Exploit, Other_Notes, Potential_Mitigations, Relationship_Notes, Relationships, Weakness_Ordinalities | | 2009-03-10 | CWE Content Team | MITRE | | updated Potential_Mitigations | | 2009-05-27 | CWE Content Team | MITRE | | updated Description, Relationships | | 2009-07-27 | CWE Content Team | MITRE | | updated Demonstrative_Examples, Related_Attack_Patterns | | 2009-10-29 | CWE Content Team | MITRE | | updated Other_Notes | | 2010-02-16 | CWE Content Team | MITRE | | updated Potential_Mitigations, Relationships | | 2010-06-21 | CWE Content Team | MITRE | | updated Detection_Factors, Potential_Mitigations | | 2010-12-13 | CWE Content Team | MITRE | | updated Demonstrative_Examples | | 2011-03-29 | CWE Content Team | MITRE | | updated Weakness_Ordinalities | | 2011-06-01 | CWE Content Team | MITRE | | updated Common_Consequences, Relationships, Taxonomy_Mappings | | 2011-06-27 | CWE Content Team | MITRE | | updated Common_Consequences | | 2011-09-13 | CWE Content Team | MITRE | | updated Relationships, Taxonomy_Mappings | | 2012-05-11 | CWE Content Team | MITRE | | updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings | | 2014-02-18 | CWE Content Team | MITRE | | updated Demonstrative_Examples | | 2014-06-23 | CWE Content Team | MITRE | | updated Related_Attack_Patterns | | 2014-07-30 | CWE Content Team | MITRE | | updated Relationships, Taxonomy_Mappings | | 2015-12-07 | CWE Content Team | MITRE | | updated Relationships | | 2017-01-19 | CWE Content Team | MITRE | | updated Relationships | | 2017-05-03 | CWE Content Team | MITRE | | updated Related_Attack_Patterns | | 2017-11-08 | CWE Content Team | MITRE | | updated Applicable_Platforms, Functional_Areas, Likelihood_of_Exploit, Relationships, Taxonomy_Mappings | | 2019-01-03 | CWE Content Team | MITRE | | updated Relationships, Taxonomy_Mappings, Type | | 2019-06-20 | CWE Content Team | MITRE | | updated Related_Attack_Patterns, Relationships | | 2020-02-24 | CWE Content Team | MITRE | | updated Relationships | | 2020-06-25 | CWE Content Team | MITRE | | updated Relationships | | 2020-08-20 | CWE Content Team | MITRE | | updated Relationships | | 2020-12-10 | CWE Content Team | MITRE | | updated Relationships | | 2021-03-15 | CWE Content Team | MITRE | | updated Demonstrative_Examples | | 2021-07-20 | CWE Content Team | MITRE | | updated Related_Attack_Patterns | | 2022-10-13 | CWE Content Team | MITRE | | updated Relationships | | 2023-01-31 | CWE Content Team | MITRE | | updated Description, Detection_Factors | | 2023-04-27 | CWE Content Team | MITRE | | updated Detection_Factors, Relationships, Time_of_Introduction | | 2023-06-29 | CWE Content Team | MITRE | | updated Mapping_Notes | | 2023-10-26 | CWE Content Team | MITRE | | updated Observed_Examples |
More information is available — Please edit the custom filter or select a different filter.
|