Improper Handling of Insufficient Permissions or Privileges
Draft Base
Structure: Simple
Description
The product does not handle or incorrectly handles when it has insufficient privileges to access resources or functionality as specified by their permissions. This may cause it to follow unexpected code paths that may leave the product in an invalid state.
Common Consequences 1
Scope: Other
Impact: OtherAlter Execution Logic
Potential Mitigations 2
Phase: Architecture and Design
Strategy: Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Phase: Implementation
Always check to see if you have successfully accessed a resource or system functionality, and use proper error handling if it is unsuccessful. Do this even when you are operating in a highly privileged mode, because errors or environmental conditions might still cause a failure. For example, environments with highly granular permissions/privilege models, such as Windows or Linux capabilities, can cause unexpected failures.
Observed Examples 2
CVE-2003-0501Special file system allows attackers to prevent ownership/permission change of certain entries by opening the entries before calling a setuid program.
CVE-2004-0148FTP server places a user in the root directory when the user's permissions prevent access to the their own home directory.
Applicable Platforms
Languages:
Not Language-Specific : Undetermined
Modes of Introduction
Implementation
Related Weaknesses
Taxonomy Mapping
- PLOVER
- WASC
- Software Fault Patterns
Notes
MaintenanceImproper Handling of Insufficient Permissions or Privileges and Improper Handling of Insufficient Privileges are too similar. It is likely that Improper Handling of Insufficient Privileges will be deprecated in the future.
RelationshipThis can be both primary and resultant. When primary, it can expose a variety of weaknesses because a resource might not have the expected state, and subsequent operations might fail. It is often resultant from Unchecked Error Condition (Unchecked Error Condition).
TheoreticalWithin the context of vulnerability theory, privileges and permissions are two sides of the same coin. Privileges are associated with actors, and permissions are associated with resources. To perform access control, at some point the software makes a decision about whether the actor (and the privileges that have been assigned to that actor) is allowed to access the resource (based on the permissions that have been specified for that resource).
Research GapThis type of issue is under-studied, since researchers often concentrate on whether an object has too many permissions, instead of not enough. These weaknesses are likely to appear in environments with fine-grained models for permissions and privileges, which can include operating systems and other large-scale software packages. However, even highly simplistic permission/privilege models are likely to contain these issues if the developer has not considered the possibility of access failure.