Mount a Drive with Existing Data and Read Its Contents

You have access to a Linux system with an additional unmounted drive that contains a hidden flag (a regular file with a secret string inside).

Device names on the diagram are deliberately generic.

Your mission is to:

1. Discover the unmounted drive
2. Mount it somewhere in the root filesystem
3. Capture the flag from the mounted drive

You have three attempts to enter the correct flag.

sudo mount /dev/<device> /path/to/mountpoint

This challenge helps you practice discovering, mounting, and accessing filesystems in Linux. Here's a step-by-step solution:

Step 1: Discover Available Block Devices

First, you need to identify what storage devices are available on the system:

lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
vda  253:0    0  80G  0 disk /
vdb  253:16   0  20G  0 disk

Notice that /dev/vdb has no mountpoint listed, indicating it's not currently mounted.

Step 2: Create a Mount Point

Before mounting a filesystem, you need to create a directory to serve as the mount point:

sudo mkdir -p /mnt/vdb

Common locations for mount points include:

• /mnt/ - general purpose mount directory
• /media/ - often used for removable media
• Any directory you prefer (e.g., ~/foobar)

Step 3: Mount the Filesystem

Mount the /dev/vdb device to your mount point:

sudo mount /dev/vdb /mnt/vdb

If you want to verify the mount was successful:

mount | grep vdb

or

df -h

Step 4: Explore the Mounted Filesystem

Navigate to the mount point and explore the contents:

cd /mnt/vdb && ls -la

You should see a flag.txt file in the directory.

Step 5: Read the Flag

Read the contents of the flag file:

cat /mnt/vdb/flag.txt

This will display a hexadecimal string that represents the flag.

Step 6: Submit the Flag

Copy the flag value and submit it in the challenge interface. The flag should be a string containing only hexadecimal characters (0-9, a-f).

Cleanup (Optional)

After capturing the flag, you can unmount the filesystem:

sudo umount /mnt/vdb

This challenge demonstrates fundamental Linux storage management skills that are essential for system administration and troubleshooting storage-related issues.