Find SGID set files

👉 Overview

👀 What ?

Find SGID set files refers to the process of identifying files in a Unix or Linux based system that are set with the SGID (Set Group ID upon execution) permission. This is a special type of file permission that allows users to execute the file with the permissions of the group owner, rather than their own permissions. This can be both a powerful tool and a potential security risk.

🧐 Why ?

Understanding and identifying SGID files is important for both system administrators and cybersecurity professionals. From an administrative perspective, it allows for more efficient resource sharing among different users in the same group. However, from a cybersecurity standpoint, SGID files can be exploited by malicious users to gain unauthorized access to resources or perform actions that they otherwise wouldn't be able to. Therefore, it's crucial to know which files have the SGID permission set and to manage them appropriately.

⛏️ How ?

To find files with the SGID permission, you can use the 'find' command in Unix or Linux. This command searches for files in a directory hierarchy based on specified criteria. To search for SGID files, you can use the '-perm' option followed by '/2000'. For example, 'find / -perm /2000 -ls' will list all the SGID files in the system. It's important to note that you should have root access to get a comprehensive list, and caution should be exercised when changing any file permissions.

⏳ When ?

The concept of file permissions, including the SGID permission, has been a part of Unix and Linux systems since their inception. The 'find' command has also been a part of these systems for many years, making it a well-established method for locating files based on various criteria, including permissions.

⚙️ Technical Explanations

The Set Group ID (SGID) is a special permission set in Unix and Linux file systems. When this permission is applied to a file, it allows a user to execute that file with the permissions of the group that owns the file, rather than their own user permissions. This means that if a file has the SGID permission set and is owned by a particular group, any user who executes that file will do so as if they were a member of that group, regardless of their actual group memberships. This can be highly beneficial in instances where multiple users within the same group require access to a specific resource.

However, this powerful feature can also pose a security risk if not handled correctly. If a malicious user gains access to an SGID file, they might be able to execute actions they would typically be restricted from, such as accessing sensitive group-owned resources.

To manage this, Unix and Linux systems provide the 'find' command, which is a flexible tool for locating files in a directory hierarchy based on specified criteria. For instance, to find all files with the SGID permission set in the system, you can use the '-perm' option followed by '/2000'. The command looks like this: 'find / -perm /2000 -ls'.

This command will list all files with SGID permissions throughout the system. It is important to note that you should ideally have root access to obtain a comprehensive list. Extreme care should be exercised when changing any file permissions to prevent accidental security vulnerabilities.

Overall, understanding and correctly managing SGID permissions is integral for both system administrators for resource management and cybersecurity professionals for identifying and mitigating potential security risks.

Let's assume you have root access on a Linux system and you want to find all files with the SGID permission. Here's how you can do it with a detailed explanation:

1. Open a terminal window. This can usually be done by searching for 'terminal' in your system's applications menu or by using a shortcut key combination like Ctrl+Alt+T.
2. To list all files with SGID permissions, you will use the find command. This command is used for searching files in a directory hierarchy. The perm option is used to search for files based on their permission settings, and /2000 specifies SGID files. The ls option is used to list files in 'ls -dils' format. Type the following command and press Enter:

sudo find / -perm /2000 -ls

This command works as follows:

• sudo: This command is used to run the following command with root privileges. This is necessary because some files may be inaccessible to your user due to their permissions settings.
• find /: This tells the find command to search in the root directory (/) and all of its subdirectories.
• perm /2000: This option tells find to only return files that have the SGID permission set.
• ls: This option tells find to list detailed information about each file, similar to the ls -l command.

After running this command, you will see a list of all files with SGID permissions in your system. For each file, the output will show the file's permissions, the number of links, owner, group, size, time of last modification, and name.

Be careful when handling these files, as changing their permissions without understanding the potential impact can lead to security vulnerabilities.