CWE-250: Execution with Unnecessary Privileges

MITRE CWE weakness

Description

The product performs an operation at a privilege level that is higher than the minimum level required, which creates new weaknesses or amplifies the consequences of other weaknesses.

Common consequences

• Confidentiality, Integrity, Availability, Access Control: Gain Privileges or Assume Identity, Execute Unauthorized Code or Commands, Read Application Data, DoS: Crash, Exit, or Restart

Mitigations

Architecture and Design — Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Architecture and Design — Identify the functionality that requires additional privileges, such as access to privileged operating system resources. Wrap and centralize this functionality if possible, and isolate the privileged code as much as possible from other code [REF-76]. Raise privileges as late as possible, and drop them as soon as possible to avoid CWE-271. Avoid weaknesses such as CWE-288 and CWE-420 by protecting all possible communication channels that could interact with the privileged code, such as a secondary socket that is only intended to be accessed by administrators.

Architecture and Design — Identify the functionality that requires additional privileges, such as access to privileged operating system resources. Wrap and centralize this functionality if possible, and isolate the privileged code as much as possible from other code [REF-76]. Raise privileges as late as possible, and drop them as soon as possible to avoid CWE-271. Avoid weaknesses such as CWE-288 and CWE-420 by protecting all possible communication channels that could interact with the privileged code, such as a secondary socket that is only intended to be accessed by administrators.

Implementation — Perform extensive input validation for any privileged code that must be exposed to the user and reject anything that does not fit your strict requirements.

Implementation — When dropping privileges, ensure that they have been dropped successfully to avoid CWE-273. As protection mechanisms in the environment get stronger, privilege-dropping calls may fail even if it seems like they would always succeed.

References

• CWE page: https://cwe.mitre.org/data/definitions/250.html
• CWE list: https://cwe.mitre.org/data/index.html