Improper Control of Resource Identifiers ('Resource Injection')

Description

This vulnerability occurs when an application accepts user input as a resource identifier (like a file path or port number) without proper validation, allowing an attacker to access or manipulate resources outside the intended scope.

Extended Description

A resource injection flaw arises when two conditions are met. First, an attacker can control the identifier used to access a system resource, such as part of a filename, a database key, a network port, or a configuration setting. Second, by controlling this identifier, the attacker gains unauthorized capabilities—like reading sensitive files, overwriting protected data, redirecting network traffic, or altering application behavior—that would normally be restricted. In practice, this happens because the application treats unvalidated user input as a direct reference to a resource. For example, an attacker might supply a path like '../../etc/passwd' to traverse directories, or specify a remote server address to exfiltrate data. The core failure is a lack of input validation and authorization checks before the resource is accessed, effectively letting users dictate which system resources the application uses.

Common Consequences 1

Scope: ConfidentialityIntegrity

Impact: Read Application DataModify Application DataRead Files or DirectoriesModify 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.

Detection Methods 1

Automated Static AnalysisHigh

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.)

Potential Mitigations 1

Phase: Implementation

Strategy: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list 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. This 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, it can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Demonstrative Examples 2

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.

Code Example:Bad
Java
java

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.

Code Example:Bad
C++
c++

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.

Observed Examples 1

CVE-2013-4787chain: mobile OS verifies cryptographic signature of file in an archive, but then installs a different file with the same name that is also listed in the archive.

References 2

Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors

Katrina Tsipenyuk, Brian Chess, and Gary McGraw

NIST Workshop on Software Security Assurance Tools Techniques and Metrics • NIST

07-11-2005

https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf

ID: REF-6

Automated Source Code Security Measure (ASCSM)

Object Management Group (OMG)

01-2016

http://www.omg.org/spec/ASCSM/1.0/

ID: REF-962

Likelihood of Exploit

High

Applicable Platforms

Languages:

Not Language-Specific : Undetermined

Modes of Introduction

Architecture and Design

Implementation

Related Attack Patterns

Alternate Terms

Insecure Direct Object Reference

OWASP uses this term, although it is effectively the same as resource injection.

Related Weaknesses

ChildOf:

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

PeerOf:

Use of Incorrectly-Resolved Name or Reference (CWE-706)

CanAlsoBe:

External Control of File Name or Path (CWE-73)

Taxonomy Mapping

7 Pernicious Kingdoms
Software Fault Patterns
OMG ASCSM

Notes

RelationshipResource injection that involves resources stored on the filesystem goes by the name path manipulation (External Control of File Name or Path).

MaintenanceThe relationship between Improper Control of Resource Identifiers ('Resource Injection') and Externally Controlled Reference to a Resource in Another Sphere needs further investigation and clarification. They might be duplicates. Improper Control of Resource Identifiers ('Resource Injection') "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, Externally Controlled Reference to a Resource in Another Sphere effectively covers any type of resource, whether that resource is at the system layer, the application layer, or the code layer.