My University Notes
Toggle Dark/Light/Auto mode Toggle Dark/Light/Auto mode Toggle Dark/Light/Auto mode Back to homepage
  1. Main Page
  2. /
  3. Cyber Security and Digital Forensics (2021-2024)
  4. /
  5. Year 2
  6. /
  7. Ethical Hacking
  8. /
  9. Week 2 - Misconfigured File Permissions
Edit page

Week 2 - Misconfigured File Permissions

  • Everything within Linux is a file

  • File permissions can cause unauthorized users access to the contents of files

    • Meaning that the contents could be changed
    • e.g. Changing the hard coded binary passwords with a known password
    • This breaks confindentiality, Integrity, and availability

Commands

  • Export PATH=/path/to/directory
    • Changes the path variable
  • find
    • Search for files in a directory
  • locate
    • Find files by name, quickly
  • which
    • locate a command

File Permissions

User Roles:

  • U: User
  • G: Group
  • O: Others

Permissions:

  • R: Read
  • W: Write
  • X: Execute

Set User identidy (SETUID/SUID)

If there is an ‘S’ in the file permissions, it is a special permission for the user access level and always executes as the user who own the file. - chmod u+s <file/dir>

Set Group Identity (SGID)

Allows a file to be executed as the group owner of the file - chmod g+s <file/dir>

Sticky Bit

Restricts the deletion at directory level - chmod o+t <file/dir>

  • U - User
  • G - Group
  • S - SUID

Commands

  • chmod <Permision> file
    • Change file permissions
  • chgrp <Group/GID> file
    • Change group ownership of a file
  • chown <User/UID> file
    • Change User ownership of a file
  • sudo <command>
    • Run the command as the root user

chmod Calculator