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Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

CWE/SANS Top 25 Most Dangerous Software Errors
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ID

CWE-99: Improper Control of Resource Identifiers ('Resource Injection')

Weakness ID: 99
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The software receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control.
+ Extended Description

A resource injection issue occurs when the following two conditions are met:

  1. An attacker can specify the identifier used to access a system resource. For example, an attacker might be able to specify part of the name of a file to be opened or a port number to be used.
  2. By specifying the resource, the attacker gains a capability that would not otherwise be permitted. For example, the program may give the attacker the ability to overwrite the specified file, run with a configuration controlled by the attacker, or transmit sensitive information to a third-party server.

This may enable an attacker to access or modify otherwise protected system resources.

+ Relationships

The table(s) below 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 "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)
+ Relevant to the view "Architectural Concepts" (CWE-1008)
NatureTypeIDName
MemberOfCategoryCategory1019Validate Inputs
+ 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 software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

PhaseNote
Architecture and Design
ImplementationREALIZATION: This weakness is caused during implementation of an architectural security tactic.
+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

(Language-Independent classes): (Undetermined Prevalence)

+ Common Consequences

The table below 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.

ScopeImpactLikelihood
Confidentiality
Integrity

Technical Impact: Read Application Data; Modify Application Data; Read Files or Directories; Modify Files or Directories

An attacker could gain access to or modify sensitive data or system resources. This could allow access to protected files or directories including configuration files and files containing sensitive information.
+ Alternate Terms
Insecure Direct Object Reference:OWASP uses this term, although it is effectively the same as resource injection.
+ Likelihood Of Exploit
High
+ Demonstrative Examples

Example 1

The following Java code uses input from an HTTP request to create a file name. The programmer has not considered the possibility that an attacker could provide a file name such as "../../tomcat/conf/server.xml", which causes the application to delete one of its own configuration files.

(bad)
Example Language: Java 
String rName = request.getParameter("reportName");
File rFile = new File("/usr/local/apfr/reports/" + rName);
...
rFile.delete();

Example 2

The following code uses input from the command line to determine which file to open and echo back to the user. If the program runs with privileges and malicious users can create soft links to the file, they can use the program to read the first part of any file on the system.

(bad)
Example Language: C++ 
ifstream ifs(argv[0]);
string s;
ifs >> s;
cout << s;

The kind of resource the data affects indicates the kind of content that may be dangerous. For example, data containing special characters like period, slash, and backslash, are risky when used in methods that interact with the file system. (Resource injection, when it is related to file system resources, sometimes goes by the name "path manipulation.") Similarly, data that contains URLs and URIs is risky for functions that create remote connections.

+ Potential Mitigations

Phase: Implementation

Strategy: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a whitelist of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs (i.e., do not rely on a blacklist). A blacklist is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, blacklists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
+ Weakness Ordinalities
OrdinalityDescription
Primary
(where the weakness exists independent of other weaknesses)
+ 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.
+ Notes

Maintenance

The relationship between CWE-99 and CWE-610 needs further investigation and clarification. They might be duplicates. CWE-99 "Resource Injection," as originally defined in Seven Pernicious Kingdoms taxonomy, emphasizes the "identifier used to access a system resource" such as a file name or port number, yet it explicitly states that the "resource injection" term does not apply to "path manipulation," which effectively identifies the path at which a resource can be found and could be considered to be one aspect of a resource identifier. Also, CWE-610 effectively covers any type of resource, whether that resource is at the system layer, the application layer, or the code layer.

Relationship

Resource injection that involves resources stored on the filesystem goes by the name path manipulation (CWE-73).

Other

A resource injection issue occurs when the following two conditions are met:

  1. An attacker can specify the identifier used to access a system resource. For example, an attacker might be able to specify part of the name of a file to be opened or a port number to be used.
  2. By specifying the resource, the attacker gains a capability that would not otherwise be permitted. For example, the program may give the attacker the ability to overwrite the specified file, run with a configuration controlled by the attacker, or transmit sensitive information to a third-party server.

Note: Resource injection that involves resources stored on the filesystem goes by the name path manipulation and is reported in a separate category. See the path manipulation description for further details of this vulnerability.

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsResource Injection
Software Fault PatternsSFP24Tainted input to command
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
7 Pernicious Kingdoms
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-08-01KDM Analytics
added/updated white box definitions
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2009-05-27CWE Content TeamMITRE
updated Description, Name
2009-07-17KDM Analytics
Improved the White_Box_Definition
2009-07-27CWE Content TeamMITRE
updated White_Box_Definitions
2011-06-01CWE Content TeamMITRE
updated Common_Consequences, Other_Notes
2012-05-11CWE Content TeamMITRE
updated Common_Consequences, Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2013-02-21CWE Content TeamMITRE
updated Alternate_Terms, Maintenance_Notes, Other_Notes, Relationships
2013-07-17CWE Content TeamMITRE
updated Relationships
2014-06-23CWE Content TeamMITRE
updated Alternate_Terms, Description, Relationship_Notes, Relationships
2014-07-30CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2015-12-07CWE Content TeamMITRE
updated Relationships
2017-01-19CWE Content TeamMITRE
updated Relationships
2017-05-03CWE Content TeamMITRE
updated Related_Attack_Patterns, Relationships
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Causal_Nature, Modes_of_Introduction, Relationships, White_Box_Definitions
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Resource Injection
2009-05-27Insufficient Control of Resource Identifiers (aka 'Resource Injection')

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Page Last Updated: November 14, 2017