CyberSecBulletin

Incorrect Permission Assignment for Critical Resource

CWE-732

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.

We track 420 vulnerabilities of this type. 100% are rated high or critical, and the average CVSS score is 8.1. 5 have been exploited in real attacks.

How this weakness is prevented

  • Implementation: When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user), and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
  • Architecture and Design: Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly. This will allow you to maintain more fine-grained control over your resources.
  • Implementation Installation: During program startup, explicitly set the default permissions or umask to the most restrictive setting possible. Also set the appropriate permissions during program installation. This will prevent you from inheriting insecure permissions from any user who installs or runs the program.
  • System Configuration: For all configuration files, executables, and libraries, make sure that they are only readable and writable by the software's administrator.
  • Documentation: Do not suggest insecure configuration changes in documentation, especially if those configurations can extend to resources and other programs that are outside the scope of the application.

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