In Unix, "others" class refers to all users except the owner of the file and the members of the group assigned to this file.
In Windows, "Everyone" group is similar and includes all members of the Authenticated Users group as well as the built-in Guest account, and
several other built-in security accounts.
Granting permissions to these groups can lead to unintended access to files.
Ask Yourself Whether
- The application is designed to be run on a multi-user environment.
- Corresponding files and directories may contain confidential information.
There is a risk if you answered yes to any of those questions.
Recommended Secure Coding Practices
The most restrictive possible permissions should be assigned to files and directories.
Sensitive Code Example
.Net Framework:
var unsafeAccessRule = new FileSystemAccessRule("Everyone", FileSystemRights.FullControl, AccessControlType.Allow);
var fileSecurity = File.GetAccessControl("path");
fileSecurity.AddAccessRule(unsafeAccessRule); // Sensitive
fileSecurity.SetAccessRule(unsafeAccessRule); // Sensitive
File.SetAccessControl("fileName", fileSecurity);
.Net / .Net Core
var fileInfo = new FileInfo("path");
var fileSecurity = fileInfo.GetAccessControl();
fileSecurity.AddAccessRule(new FileSystemAccessRule("Everyone", FileSystemRights.Write, AccessControlType.Allow)); // Sensitive
fileInfo.SetAccessControl(fileSecurity);
.Net / .Net Core using Mono.Posix.NETStandard
var fileSystemEntry = UnixFileSystemInfo.GetFileSystemEntry("path");
fileSystemEntry.FileAccessPermissions = FileAccessPermissions.OtherReadWriteExecute; // Sensitive
Compliant Solution
.Net Framework
var safeAccessRule = new FileSystemAccessRule("Everyone", FileSystemRights.FullControl, AccessControlType.Deny);
var fileSecurity = File.GetAccessControl("path");
fileSecurity.AddAccessRule(safeAccessRule);
File.SetAccessControl("path", fileSecurity);
.Net / .Net Core
var safeAccessRule = new FileSystemAccessRule("Everyone", FileSystemRights.FullControl, AccessControlType.Deny);
var fileInfo = new FileInfo("path");
var fileSecurity = fileInfo.GetAccessControl();
fileSecurity.SetAccessRule(safeAccessRule);
fileInfo.SetAccessControl(fileSecurity);
.Net / .Net Core using Mono.Posix.NETStandard
var fs = UnixFileSystemInfo.GetFileSystemEntry("path");
fs.FileAccessPermissions = FileAccessPermissions.UserExecute;
See
