CVE-2020-1571

An elevation of privilege vulnerability exists in Windows Setup in the way it handles permissions. A locally authenticated attacker could run arbitrary code with elevated system privileges. After successfully exploiting the vulnerability, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. The security update addresses the vulnerability by ensuring Windows Setup properly handles permissions.

Weakness

During installation, installed file permissions are set to allow anyone to modify those files.

Affected Software

Potential Mitigations

• 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.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/1.html
• https://cwe.mitre.org/data/definitions/127.html
• https://cwe.mitre.org/data/definitions/81.html

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1571