chmod 777 vs 755
| Property | chmod 777 | chmod 755 |
|---|---|---|
| Octal | 777 |
755 |
| Symbolic | rwxrwxrwx |
rwxr-xr-x |
| Owner | read/write/execute | read/write/execute |
| Group | read/write/execute | read/execute |
| Others | read/write/execute | read/execute |
| Risk Level | Critical Risk | Low Risk |
| Typical Use | Short-lived local debugging and testing only | Standard Linux directories and folder structures |
Key Difference
- Group: chmod 777 grants read/write/execute (7), while chmod 755 grants read/execute (5).
- Others: chmod 777 grants read/write/execute (7), while chmod 755 grants read/execute (5).
Which Should You Use?
There is virtually no legitimate scenario on a production Linux server where chmod 777 is justified. Mode 777 grants universal read, write, and execute permissions to every single account and process on the operating system. If a single unprivileged background process or third-party web script is compromised, an attacker can overwrite, inject, or delete files in any 777 directory. Junior developers often resort to "chmod -R 777" to hastily resolve "Permission Denied" errors, inadvertently introducing catastrophic security vulnerabilities. The correct, secure alternative is chmod 755 for directories and chmod 644 for files, combined with proper user and group ownership via chown. Mode 755 preserves full control for the administrator while allowing the web server to read and serve assets without permitting destructive writes.
Frequently Asked Questions
Is 755 more secure than 777?
Yes, drastically more secure. Mode 755 blocks world write access, ensuring that outside users and malicious scripts cannot modify, replace, or delete your files.
Can I convert 777 to 755?
Yes. To fix a directory improperly set to 777, run "chmod 755 /path/to/dir". For an entire folder hierarchy, use "find /path -type d -exec chmod 755 {} +" to update directories safely.
Which is better for web servers?
Mode 755 is the industry standard for web servers. Never use 777 on web document roots or uploads directories, as it invites remote code execution and webshell injection.
Related Permissions & Comparisons
Read in-depth breakdowns for chmod 777 (rwxrwxrwx) and chmod 755 (rwxr-xr-x), or browse other permission comparisons: