CWE-913: Improper Control of Dynamically-Managed Code Resources

Extended Description

Many languages offer powerful features that allow the programmer to dynamically create or modify existing code, or resources used by code such as variables and objects. While these features can offer significant flexibility and reduce development time, they can be extremely dangerous if attackers can directly influence these code resources in unexpected ways.

Code Examples & CVEs

Demonstrative Examples

This example attempts to write user messages to a message file and allow users to view them.

While the programmer intends for the MessageFile to only include data, an attacker can provide a message such as:

BadPHP

$MessageFile = "messages.out";if ($_GET["action"] == "NewMessage") {$name = $_GET["name"];$message = $_GET["message"];$handle = fopen($MessageFile, "a+");fwrite($handle, "<b>$name</b> says '$message'<hr>\n");fclose($handle);echo "Message Saved!<p>\n";}else if ($_GET["action"] == "ViewMessages") {include($MessageFile);}

A common reason that programmers use the reflection API is to implement their own command dispatcher. The following example shows a command dispatcher that does not use reflection:

A programmer might refactor this code to use reflection as follows:

GoodJava

String ctl = request.getParameter("ctl"); 				  Worker ao = null; 				  if (ctl.equals("Add")) { 				   				  ao = new AddCommand(); 				   				  } 				  else if (ctl.equals("Modify")) { 				   				  ao = new ModifyCommand(); 				   				  } 				  else { 				   				  throw new UnknownActionError(); 				  } 				   				  ao.doAction(request);

A common reason that programmers use the reflection API is to implement their own command dispatcher. The following example shows a command dispatcher that does not use reflection:

A programmer might refactor this code to use reflection as follows:

BadJava

String ctl = request.getParameter("ctl"); 					Class cmdClass = Class.forName(ctl + "Command"); 					Worker ao = (Worker) cmdClass.newInstance(); 					ao.doAction(request);

A common reason that programmers use the reflection API is to implement their own command dispatcher. The following example shows a command dispatcher that does not use reflection:

A programmer might refactor this code to use reflection as follows:

BadJava

String ctl = request.getParameter("ctl"); 				   Class cmdClass = Class.forName(ctl + "Command"); 				   Worker ao = (Worker) cmdClass.newInstance(); 				   ao.checkAccessControl(request); 				   ao.doAction(request);

Observed CVE Examples (5)

CVE-2022-2054

Python compiler uses eval() to execute malicious strings as Python code.

View Details

CVE-2018-1000613

Cryptography API uses unsafe reflection when deserializing a private key

View Details

CVE-2015-8103

Deserialization issue in commonly-used Java library allows remote execution.

View Details

CVE-2006-7079

Chain: extract used for register_globals compatibility layer, enables path traversal (CWE-22)

View Details

CVE-2012-2055

Source version control product allows modification of trusted key using mass assignment.

View Details

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-913 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-913, Improper Control of Dynamically-Managed Code Resources, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Apply Input Validation controls for Improper Control of Dynamically-Managed Code Resources

MITRE associates mitigation with Implementation, and Architecture and Design; the listed strategies include Input Validation, and Refactoring; documented detection approaches include Fuzzing. Use these source-defined anchors to turn CWE-913 into implementation, review, and verification checks for the affected component.

CWE-913: Improper Control of Dynamically-Managed Code Resources — MITRE CWE

Triage CWE-913 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-913, Improper Control of Dynamically-Managed Code Resources, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-913

Apply MITRE's full root-cause mapping guidance when using CWE-913, Improper Control of Dynamically-Managed Code Resources. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-913 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-913, Improper Control of Dynamically-Managed Code Resources. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-913: Improper Control of Dynamically-Managed Code Resources?+

CWE-913: Improper Control of Dynamically-Managed Code Resources is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product does not properly restrict reading from or writing to dynamically-managed code resources such as variables, objects, classes, attributes, functions, or executable instructions or statements. Many languages offer powerful features that allow the programmer to dynamically create or modify existing code, or resources used by code such as variables and objects. While these features can offer significant flexibility and reduce development time, they can be extremely dangerous if attackers can directly influence these code resources in unexpected ways.

What are the security consequences of Improper Control of Dynamically-Managed Code Resources?+

If exploited, CWE-913 (Improper Control of Dynamically-Managed Code Resources) it can compromise Integrity and Other, leading to outcomes such as Execute Unauthorized Code or Commands, Varies by Context and Alter Execution Logic.

How do you prevent or mitigate Improper Control of Dynamically-Managed Code Resources?+

Recommended mitigations for CWE-913 include: For any externally-influenced input, check the input against an allowlist of acceptable values. Refactor the code so that it does not need to be dynamically managed.

Which programming languages are affected by Improper Control of Dynamically-Managed Code Resources?+

CWE-913 commonly affects Not Language-Specific and Interpreted. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Improper Control of Dynamically-Managed Code Resources?+

MITRE documents real CVEs mapped to CWE-913, including CVE-2022-2054, CVE-2018-1000613, CVE-2015-8103, CVE-2006-7079 and CVE-2012-2055. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-913 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-913: Improper Control of Dynamically-Managed Code Resources

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Scope

Impact

Mitigation Strategies

Phase

Description

Strategy

Phase

Description

Strategy

Detection Methods

Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (5)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-913 with SSDF evidence

Apply Input Validation controls for Improper Control of Dynamically-Managed Code Resources

Triage CWE-913 against known exploitation evidence

Apply precise root-cause mapping to CWE-913

Validate CWE-913 with root-cause mapping checks

Frequently Asked Questions

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