In Unix file system permissions, the "others" category refers to all users except the owner of the file system resource and the
members of the group assigned to this resource.
Granting permissions to this category can lead to unintended access to files or directories that could allow attackers to obtain sensitive information, disrupt services or elevate privileges.
When file or directory permissions grant access to all users on a system (often represented as "others" or "everyone" in permission models), attackers who gain access to any user account can read sensitive files containing credentials, configuration data, API keys, database passwords, personal information, or proprietary business data. This exposure can lead to data breaches, identity theft, compliance violations, and competitive disadvantage.
Granting write permissions to broad user categories allows any user on the system to modify or delete critical files and directories. Attackers or compromised low-privileged accounts can corrupt application data, modify configuration files to alter system behavior or disrupt services, or delete important resources, leading to service outages, system instability, data loss, and denial of service.
When executable files or scripts have overly permissive permissions, especially when combined with special permission bits that allow programs to execute with the permissions of the file owner or group rather than the executing user, attackers can replace legitimate executables with malicious code. When these modified files are executed by privileged users or processes, the attacker’s code runs with elevated privileges, potentially enabling them to escalate from a low-privileged account to root or administrator access, install backdoors, or pivot to other systems in the network.
The most restrictive possible permissions should be assigned to files and directories. Use chmod() with appropriate permission values that restrict access to the "others" category. For example, use 0750 instead of 0777 to prevent any access from "others".
chmod("foo", 0777); // Noncompliant
chmod("foo", 0750);
When using umask(), set it to a value that restricts permissions for the "others" category. The umask value 0027 ensures that newly created files and directories do not grant any permissions to "others".
umask(0); // Noncompliant umask(0750); // Noncompliant
umask(0027);
When using Laravel’s Filesystem component, ensure that chmod() is called with restrictive permission values. Use 0750 instead of 0777 to prevent access from the "others" category.
use Illuminate\Filesystem\Filesystem;
$fs = new Filesystem();
$fs->chmod("foo", 0777); // Noncompliant
use Illuminate\Filesystem\Filesystem;
$fs = new Filesystem();
$fs->chmod("foo", 0750);
When using Symfony’s Filesystem component, ensure that chmod() is called with restrictive permission values. Use 0750 instead of 0777 to prevent access from the "others" category.
use Symfony\Component\Filesystem\Filesystem;
$fs = new Filesystem();
$fs->chmod("foo", 0777); // Noncompliant
use Symfony\Component\Filesystem\Filesystem;
$fs = new Filesystem();
$fs->chmod("foo", 0750);