UnderTheWire: Century

Platform: UnderTheWire Goal: Learn PowerShell nuances. Format: Connect via SSH, solve the puzzle to get the password for the next user.

Connection Info

Host: century.underthewire.tech Port: 22 (Standard SSH)

Century 0 -> 1

Goal: Connect to the server. User: century1 Pass: century1

ssh century1@century.underthewire.tech

Task: Find the build version of the PowerShell host.

$PSVersionTable.BuildVersion
# Output: 10.0.14393.0

Password: century2

Century 1 -> 2

Goal: Find the build number of Internet Explorer. Concept: Registry Query.

Get-ItemProperty "HKLM:\Software\Microsoft\Internet Explorer" | Select-Object svcVersion

(Note: In newer Windows versions, this might move, but UTW keeps it legacy compatible).

Century 2 -> 3

Goal: Count the number of files in the Desktop directory. Concept: Measure-Object.

Get-ChildItem -Path "Desktop" | Measure-Object
# Count: 123 (Example)

Century 3 -> 4

Goal: Find the name of the file with the largest size in the Desktop. Concept: Sorting objects.

Get-ChildItem -Path "Desktop" | Sort-Object Length -Descending | Select-Object -First 1 -ExpandProperty Name

Century 4 -> 5

Goal: Find the name of the file that has "password" in the content. Concept: Select-String (PowerShell's Grep).

Get-ChildItem -Path "Desktop" | Select-String "password"

Century 5 -> 6

Goal: Find the DNS server address. Concept: Get-DnsClientServerAddress.

Get-DnsClientServerAddress

Century 6 -> 7

Goal: Find the 6th line of a file. Concept: Array indexing.

(Get-Content .\file.txt)[5]
# Note: 0-indexed, so 5 is the 6th line.

Century 7 -> 8

Goal: Count the number of files in the current directory. Concept: Measure-Object.

Get-ChildItem | Measure-Object

Century 8 -> 9

Goal: Find the user with the most unique property values. Concept: Get-User (likely AD) or custom object. (Actually, UTW often focuses on file properties here). Correction: Find the file with the most unique words? UTW Specific: "The password is the number of unique entries in the file."

Get-Content file.txt | Sort-Object | Get-Unique | Measure-Object

Century 9 -> 10

Goal: Find the word that appears the most times. Concept: Grouping.

Get-Content file.txt | Group-Object | Sort-Object Count -Descending | Select-Object -First 1

Century 10 -> 11

Goal: Use Get-Member to find a specific method on an object. Concept: Introspection.

$Obj | Get-Member
# Look for Method matching description (e.g., .Convert())

Century 11 -> 12

Goal: Find the name of the service that starts with "M" and is Stopped. Concept: Get-Service.

Get-Service -Name M* | Where-Object {$_.Status -eq 'Stopped'}

Century 12 -> 13

Goal: Find the description of a specific Event Log ID. Concept: Get-EventLog or Get-WinEvent.

Get-WinEvent -LogName Application -MaxEvents 1 | Select-Object Message

Century 13 -> 14

Goal: Reverse a string. Concept: [Array]::Reverse.

$str = "Password"
$arr = $str.ToCharArray()
[Array]::Reverse($arr)
-join $arr

Century 14 -> 15

Goal: Find the number of lines in a file, but exclude empty lines. Concept: Filtering.

Get-Content file.txt | Where-Object {$_ -ne ""} | Measure-Object

Verdict: If Bandit teaches specific bytes, Century teaches Objects. Understanding that every output in PowerShell is an object (not text) is the key to Windows Administration.