Worldwritable

Worldwritable is a security term describing a file or directory whose permissions allow write access to all users (others) on a Unix-like system. When a file is world-writable, any user can modify its contents; when a directory is world-writable, any user can create, rename, or delete entries within it. World-writable items are commonly indicated by permission bits such as 0777, though a directory may retain some protective restrictions if the sticky bit is set (for example, 1777 on /tmp), which limits deletions to the file owner.

The concept carries significant risk. World-writable files can be overwritten with malicious content, and world-writable directories enable arbitrary file creation or replacement, which can facilitate malware uploads, code injection, or tampering with data. In shared environments or hosting scenarios, attackers may exploit such permissions to execute unauthorized actions or escalate privileges, especially if executable files are writable or if critical system components are exposed.

Common locations include temporary and public directories such as /tmp and /var/tmp, web server document roots or upload folders, and misconfigured user home directories. Regularly scanning for world-writable permissions helps detect potential exposures.

Detection and remediation involve auditing with commands like ls -ld on paths and finding world-writable items (for example, find / -perm -0002 -type f -print and find / -perm -0002 -type d -print). Remediation typically means removing world-writable permissions (chmod o-w) or restricting access with more restrictive modes (e.g., 0755 for directories, 0644 for files), enabling the sticky bit where appropriate, and applying principle of least privilege. Validation and periodic reviews are recommended to maintain secure configurations. World-writable is a Unix-centric term; similar concepts apply on Windows through permissive ACLs.