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Important UNIX Files and their Permissions

Early Unix systems were mainly commercial commodities like most software for sale; to run the operating system, you generally had to pay for that right. In 1984 an engineer named Richard Stallman began work on the GNU Project, which was an effort to create an operating system that was like Unix and that could be distributed and used freely by anyone. He currently runs the Free Software Foundation, and many of the programs he and his supporters have created are used in both commercial and open-source versions of Unix.

In 1991 Linus Torvalds, a Finnish graduate student, began work on a Unix-like system called Linux. Linux is actually the kernel, while the parts with which most people are familiar—the tools, shell, and file system—are the creations of others (usually the GNU organization).

As the Linux project gained momentum, it grew into a major contender in the Unix market. Many people are first introduced to Unix through Linux, which makes available to desktop machines the functionality of a Unix machine that used to costs thousands of dollars. The strength of Linux lies in its progressive licensing, which allows for the software to be freely distributable with no royalty requirements.

The permissions of a file are the first line of defense in the security of a Unix system. The basic building blocks of Unix permissions are the read, write, and execute permissions, which are described in the following table:

Permission Applied to a Directory Applied to Any Other Type of File
read (r) Grants the capability to read the contents of the directory or subdirectories. Grants the capability to view the file.
write (w) Grants the capability to create, modify, or remove files or subdirectories. Grants write permissions, allowing an authorized entity to modify the file, such as by adding text to a text file, or deleting the file.
execute (x) Grants the capability to enter the directory. Allows the user to “run” the program.
No permission. No permission.

To change file or directory permissions, you use the chmod (change mode) command. There are two ways to use chmod: symbolic mode and absolute mode.

Applying permissions with chmod’s absolute mode requires a numerical representation of the permissions, which is more efficient and is how the system views permissions. Permissions applied with chmod’s symbolic mode use the familiar rwx format and are easier to understand for most new users.

A file system is a component of Unix that enables the user to view, organize, secure, and interact with files and directories that are located on storage devices.

Everything in Unix is considered to be a file, including physical devices such as DVD-ROMs, USB devices, floppy drives, and so forth. This use of files allows Unix to be consistent in its treatment of resources and gives the user a consistent mechanism of interaction with the system. It’s easy to understand, then, why file systems are an integral part of a Unix operating system.

Here is the complete list of UNIX File structure and their recommended permissions:

Filename User Group Permissions
/bin root root drwxr-xr-x
/etc root root drwxr-xr-x
/etc/aliases root root -rw-r–r–
/etc/default/login root root -rw——-
/etc/exports root root -rw-r–r–
/etc/hosts root root -rw-rw-r–
/etc/hosts.allow root root -rw——-
/etc/hosts.deny root root -rw——-
/etc/hosts.equiv root root -rw——-
/etc/hosts.lpd root root -rw——-
/etc/inetd.conf root root -rw——-
/etc/issue root root -rw-r–r–
/etc/login.access root root -rw——-
/etc/login.conf root root -rw——-
/etc/login.defs root root -rw——-
/etc/motd root root -rw-r–r–
/etc/mtab root root -rw-r–r–
/etc/netgroup root root -rw——-
/etc/passwd root root -rw-r–r–
/etc/rc.d root root drwx——
/etc/rc.local root root -rw——-
/etc/rc.sysinit root root -rw——-
/etc/sercuetty root root -rw——-
/etc/security root root -rw——-
/etc/services root root -rw-r–r–
/etc/shadow root root -r——–
/etc/ssh/ssh_host_key root root -rw——-
/etc/ssh/sshd_config root root -rw——-
/etc/ssh/ssh_host_dsa_key root root -rw——-
/etc/ssh/ssh_host_key root root -rw——-
/etc/ssh/ssh_host_rsa_key root root -rw——-
/etc/ttys root root -rw——-
/root root root drwx——
/sbin root root drwxr-xr-x
/tmp root root drwxrwxrwt
/usr/bin root root drwxr-xr-x
/usr/etc root root drwxr-xr-x
/usr/sbin root root drwxr-xr-x
/var/log root root drwxr-xr-x
/var/log/authlog* root root -rw——-
/var/log/boot* root root -rw——-
/var/log/cron* root root -rw——-
/var/log/dmesg root root -rw——-
/var/log/lastlog root root -rw——-
/var/log/maillog* root root -rw——-
/var/log/messages* root root -rw——-
/var/log/secure* root root -rw——-
/var/log/spooler* root root -rw——-
/var/log/syslog* root root -rw——-
/var/log/utmp* root utmp -rw-rw-r–
/var/log/wtmp* root utmp -rw-rw-r–
/var/log/xferlog root root -rw——-
/var/run root root drwxr-xr-x
/var/run/*.pid root/user root/user -rw-r–r–
/var/spool/cron root root drwx——
/var/spool/cron/crontabs/root root root -r——–
/var/spool/mail root mail drwxrwxr-x
/var/spool/mail/* user user -rw-rw—-
/var/tmp root root drwxrwxrwt

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H4ck0
Step by step hacking tutorials about wireless cracking, kali linux, metasploit, ethical hacking, seo tips and tricks, malware analysis and scanning.
https://www.yeahhub.com/

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