CWE-273: Improper Check for Dropped Privileges
Official CWE-273 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-273: Improper Check for Dropped Privileges
Improper Check for Dropped Privileges represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Access Control: Gain Privileges or Assume Identity: If privileges are not dropped, neither are access rights of the user. Often these rights can be prevented from being dropped.
- Access Control,Non-Repudiation: Gain Privileges or Assume Identity,Hide Activities: If privileges are not dropped, in some cases the system may record actions as the user which is being impersonated rather than the impersonator.
Developer Pattern
CWE-273 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-273, 4.20.
Official CWE Definition
CWE-273: Improper Check for Dropped Privileges
The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded.
If the drop fails, the product will continue to run with the raised privileges, which might provide additional access to unprivileged users.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- This code attempts to take on the privileges of a user before creating a file, thus avoiding performing the action with unnecessarily high privileges: The call to ImpersonateNamedPipeClient may fail, but the return value is not checked. If the call fails, the code may execute with higher privileges than intended. In this case, an attacker could exploit this behavior to write a file to a location that the attacker does not have access to.
Remediation
- Architecture and Design: [object Object]
- Implementation: Check the results of all functions that return a value and verify that the value is expected.
- Implementation: In Windows, make sure that the process token has the SeImpersonatePrivilege(Microsoft Server 2003). Code that relies on impersonation for security must ensure that the impersonation succeeded, i.e., that a proper privilege demotion happened.
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
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.