CWE-453: Insecure Default Variable Initialization
Official CWE-453 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-453: Insecure Default Variable Initialization
Insecure Default Variable Initialization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Integrity: Modify Application Data: An attacker could gain access to and modify sensitive data or system information.
Developer Pattern
CWE-453 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.
Confidence
high confidence from CWE-453, 4.20.
Official CWE Definition
CWE-453: Insecure Default Variable Initialization
The product, by default, initializes an internal variable with an insecure or less secure value than is possible.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- This code attempts to login a user using credentials from a POST request: Because the $authorized variable is never initialized, PHP will automatically set $authorized to any value included in the POST request if register_globals is enabled. An attacker can send a POST request with an unexpected third value 'authorized' set to 'true' and gain authorized status without supplying valid credentials.,Here is a fixed version:,This code avoids the issue by initializing the $authorized variable to false and explicitly retrieving the login credentials from the $_POST variable. Regardless, register_globals should never be enabled and is disabled by default in current versions of PHP.
Remediation
- System Configuration: Disable or change default settings when they can be used to abuse the system. Since those default settings are shipped with the product they are likely to be known by a potential attacker who is familiar with the product. For instance, default credentials should be changed or the associated accounts should be disabled.
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
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.