Improper Check for Dropped Privileges

Opis

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.

Skutki

• 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.

Zapobieganie

• Architecture and Design · 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.

• Implementation

  Check the results of all functions that return a value and verify that the value is expected.

  Skuteczność: High

• 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.

Przykłady podatności

• CVE-2006-4447 Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.
• CVE-2006-2916 Program does not check return value when invoking functions to drop privileges, which could leave users with higher privileges than expected by forcing those functions to fail.

Słabość nadrzędna

• CWE-754 Improper Check for Unusual or Exceptional Conditions
• CWE-271 Privilege Dropping / Lowering Errors

Pokrewna

• CWE-252 Unchecked Return Value

Kiedy powstaje

• Implementation — REALIZATION: This weakness is caused during implementation of an architectural security tactic. This issue is likely to occur in restrictive environments in which the operating system or application provides fine-grained control over privilege management.

Dotyczy

Not Language-Specific

Źródła

1. The CLASP Application Security Process — Secure Software, Inc., 2005