java.lang.security.audit.overly-permissive-file-permission.overly-permissive-file-permission

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Detected file permissions that are overly permissive (read, write, and execute). It is generally a bad practices to set overly permissive file permission such as read+write+exec for all users. If the file affected is a configuration, a binary, a script or sensitive data, it can lead to privilege escalation or information leakage. Instead, follow the principle of least privilege and give users only the permissions they need.

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Defintion

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rules:
  - id: overly-permissive-file-permission
    message: Detected file permissions that are overly permissive (read, write, and
      execute). It is generally a bad practices to set overly permissive file
      permission such as read+write+exec for all users. If the file affected is
      a configuration, a binary, a script or sensitive data, it can lead to
      privilege escalation or information leakage. Instead, follow the principle
      of least privilege and give users only the  permissions they need.
    severity: WARNING
    languages:
      - java
    metadata:
      cwe:
        - "CWE-276: Incorrect Default Permissions"
      owasp:
        - A01:2021 - Broken Access Control
      source-rule-url: https://find-sec-bugs.github.io/bugs.htm#OVERLY_PERMISSIVE_FILE_PERMISSION
      category: security
      technology:
        - java
      references:
        - https://owasp.org/Top10/A01_2021-Broken_Access_Control
      cwe2022-top25: true
      cwe2021-top25: true
      subcategory:
        - audit
      likelihood: LOW
      impact: MEDIUM
      confidence: LOW
      license: Commons Clause License Condition v1.0[LGPL-2.1-only]
    pattern-either:
      - pattern: java.nio.file.Files.setPosixFilePermissions($FILE,
          java.nio.file.attribute.PosixFilePermissions.fromString("=~/(^......r..$)|(^.......w.$)|(^........x$)/"));
      - pattern: >
          $TYPE $P =
          java.nio.file.attribute.PosixFilePermissions.fromString("=~/(^......r..$)|(^.......w.$)|(^........x$)/");

          ...

          java.nio.file.Files.setPosixFilePermissions($FILE, $P);
      - pattern: |
          $P.add(java.nio.file.attribute.PosixFilePermission.OTHERS_READ);
          ...
          java.nio.file.Files.setPosixFilePermissions($FILE, $P);
      - pattern: |
          $P.add(java.nio.file.attribute.PosixFilePermission.OTHERS_WRITE);
          ...
          java.nio.file.Files.setPosixFilePermissions($FILE, $P);
      - pattern: |-
          $P.add(java.nio.file.attribute.PosixFilePermission.OTHERS_EXECUTE);
          ...
          java.nio.file.Files.setPosixFilePermissions($FILE, $P);

Examples

overly-permissive-file-permission.java

package testcode.file.permissions;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.HashSet;
import java.util.Set;

public class FileApi {

    public static void notOk() throws IOException {
        // ruleid:overly-permissive-file-permission
        Files.setPosixFilePermissions(Paths.get("/var/opt/app/init_script.sh"), PosixFilePermissions.fromString("rw-rw-rw-"));
        // ruleid:overly-permissive-file-permission
        Files.setPosixFilePermissions(Paths.get("/var/opt/configuration.xml"), PosixFilePermissions.fromString("rw-rw-r--"));
    }

    public static void notOk2() throws IOException {
        Set<PosixFilePermission> perms = new HashSet<>();
        perms.add(PosixFilePermission.OWNER_READ);
        perms.add(PosixFilePermission.OWNER_WRITE);
        perms.add(PosixFilePermission.OWNER_EXECUTE);

        perms.add(PosixFilePermission.GROUP_READ);
        perms.add(PosixFilePermission.GROUP_WRITE);
        perms.add(PosixFilePermission.GROUP_EXECUTE);

        // ruleid:overly-permissive-file-permission
        perms.add(PosixFilePermission.OTHERS_READ);
        // ruleid:overly-permissive-file-permission
        perms.add(PosixFilePermission.OTHERS_WRITE);
        // ruleid:overly-permissive-file-permission
        perms.add(PosixFilePermission.OTHERS_EXECUTE);

        Files.setPosixFilePermissions(Paths.get("/var/opt/app/init_script.sh"),perms);
    }

    public static void ok() throws IOException {
        Files.setPosixFilePermissions(Paths.get("/var/opt/configuration.xml"), PosixFilePermissions.fromString("rw-rw----"));
        Files.setPosixFilePermissions(Paths.get("/var/opt/configuration.xml"), PosixFilePermissions.fromString("rwxrwx---"));
    }
}