CWE-99: Improper Control of Resource Identifiers… | Glexia
CWE-99 (Improper Control of Resource Identifiers ('Resource Injection')) weakness overview with consequences, detection methods, mitigations, related CVEs and…
Glexia's Take · Automated analysis
CWE-99: Insecure Direct Object Reference
Improper Control of Resource Identifiers ('Resource Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality Integrity: 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.
Developer Pattern
CWE-99 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-99, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-99: Improper Control of Resource Identifiers ('Resource Injection')
The product 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.
A resource injection issue occurs when the following two conditions are met: 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. 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.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- 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.
- 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. 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.
Remediation
- Implementation: 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.
Detection
- 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.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
- CWE-641: Improper Restriction of Names for Files and Other Resources
- CWE-694: Use of Multiple Resources with Duplicate Identifier
- CWE-706: Use of Incorrectly-Resolved Name or Reference
- CWE-914: Improper Control of Dynamically-Identified Variables
- CWE-706: Use of Incorrectly-Resolved Name or Reference
- CWE-73: External Control of File Name or Path
- CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.