Exam CAS-004 topic 1 question 29 discussion

/etc/passwd doesn't mean anything on modern linux systems. You would need to read /etc/shadow to get hashes if you wanna tray to crack them (and you have to be root for that). The best thing is A as this directly leads to spawning a root shell.

The answer is C. the account being used does not have super user access so they cant use sudo, as an attacker the best move would be to find out what usernames are available and maybe try to elevate my permissions using one of those user accounts found in the etcppasswd file

A. Spawn a shell using sudo and an escape string such as sudo vim -c '!sh'. Explanation Option A: This method leverages misconfigured sudo permissions that allow a standard user to run vim (or similar editors) as root. If a user can execute vim as root via sudo, they can use vim’s command mode to spawn a root shell. For example, running sudo vim -c '!sh' or entering :!sh within vim will drop the user into a root shell, effectively escalating privileges . This is a well-known and valid Linux privilege escalation technique.

✅ A) Spawn a shell using sudo and an escape string such as sudo vim -c '!sh'. ❌ C) Read the /etc/passwd file to extract usernames. /etc/passwd contains usernames, UIDs, home directories, and default shells, but not password hashes (those are stored in /etc/shadow). It’s useful for reconnaissance, but it doesn’t escalate privileges. Key Takeaway: 💡 Misconfigured sudo permissions can allow attackers to escalate privileges using escape sequences in certain programs. Always restrict unnecessary sudo access! 🔥 Burn, you’re thinking like an ethical hacker now! Want to hit another CASP+ challenge? 🚀

The command sudo vim -c '!sh' is a technique used to escalate privileges on a Linux system by exploiting the capabilities of the vim text editor.

The likelihood of a passwd being plaintext isn't very likely. This is not a database and service path is not local. Going with A, attempt to gain root Source: Verifying each answer against Chat GPT, my experience, other test banks, a written book, and weighing in the discussion from all users to create a 100% accurate guide for myself before I take the exam. (It isn't easy because of the time needed, but it is doing my diligence)

The escape string "sudo vim -c !sh'" is a commonly used method to spawn a shell as a root user in Linux. This command opens the vim text editor as a root user and executes the "sh" command to spawn a new shell with root privileges. Reading the /etc/passwd file to extract the usernames (Option C) is a reconnaissance technique that helps identify user accounts on the system but does not provide a way to elevate privileges.

A. Spawn a shell using sudo and an escape string such as sudo vim -c '!sh' is a valid Linux post-exploitation method to elevate privilege levels. This method takes advantage of the sudo command, which allows users to execute commands with elevated privileges, and the escape string "!sh" invokes a shell with root privileges.

As the account is a standard user, they will not have the rights to edit configuration files (sudoers), so the best option is to access the passwd file (you do not need any privileges to do this).

A can be possible if the Linux system is vulnerable, getting shell using Vim via Sudo If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access. sudo vim -c ':!/bin/sh' reference: https://gtfobins.github.io/gtfobins/vim/

Initiate unquoted service path exploits could also work here, no?

/etc/passwd is a plain text-based database that contains information for all user accounts on the system. It is owned by root and has 644 permissions . The file can only be modified by root or users with sudo privileges and readable by all system users. via https://linuxize.com/post/etc-passwd-file/ Seems readable by all users.

The user can't read the /etc/passswd file without elevated privileges. A

Best thing to do is read /etc/passwd file

A https://gtfobins.github.io/gtfobins/vim/