Isaca Updated CCOA Exam Questions and Answers by alfie-james

To identify thefilename of the webshellused to control the host10.10.44.200from the provided PCAP file, follow these detailed steps:

Step 1: Access the PCAP File

Log into theAnalyst Desktop.

Navigate to theInvestigationsfolder located on the desktop.

Locate the file:

investigation22.pcap

Step 2: Open the PCAP File in Wireshark

LaunchWiresharkon the Analyst Desktop.

Open the PCAP file:

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File > Open > Desktop > Investigations > investigation22.pcap

ClickOpento load the file.

Step 3: Filter Traffic Related to the Target Host

Apply a filter to display only the traffic involving thetarget IP address (10.10.44.200):

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ip.addr == 10.10.44.200

This will show both incoming and outgoing traffic from the compromised host.

Step 4: Identify HTTP Traffic

Since webshells typically use HTTP/S for communication, filter for HTTP requests:

http.request and ip.addr == 10.10.44.200

Look for suspiciousPOSTorGETrequests indicating a webshell interaction.

Common Indicators:

Unusual URLs:Containing scripts like cmd.php, shell.jsp, upload.asp, etc.

POST Data:Indicating command execution.

Response Status:HTTP 200 (Success) after sending commands.

Step 5: Inspect Suspicious Requests

Right-click on a suspicious HTTP packet and select:

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Follow > HTTP Stream

Examine the HTTP conversation for:

File uploads

Command execution responses

Webshell file namesin the URL.

Example:

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POST /uploads/shell.jsp HTTP/1.1

Host: 10.10.44.200

User-Agent: Mozilla/5.0

Content-Type: application/x-www-form-urlencoded

Step 6: Correlate Observations

If you identify a script like shell.jsp, verify it by checking multiple HTTP streams.

Look for:

Commands sent via the script.

Response indicating successful execution or error.

Step 7: Extract and Confirm

To confirm the filename, look for:

Upload requests containing the webshell.

Subsequent requests calling the same filename for command execution.

Cross-reference the filename in other HTTP streams to validate its usage.

Step 8: Example Findings:

After analyzing the HTTP streams and reviewing requests to the host 10.10.44.200, you observe that the webshell file being used is:

shell.jsp

Answer:

shell.jsp

Step 9: Further Investigation

Extract the Webshell:

Right-click the related packet and choose:

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Export Objects > HTTP

Save the file shell.jsp for further analysis.

Analyze the Webshell:

Open the file with a text editor to examine its functionality.

Check for hardcoded credentials, IP addresses, or additional payloads.

Step 10: Documentation and Response

Document Findings:

Webshell Filename:shell.jsp

Host Compromised:10.10.44.200

Indicators:HTTP POST requests, suspicious file upload.

Immediate Actions:

Isolate the host10.10.44.200.

Remove the webshell from the web server.

Conduct aroot cause analysisto determine how it was uploaded.

Step 1: Understand the Objective

Objective:

Identify thenumber of unique IP addressesthat have receivedunencrypted web connections(HTTP) during the period:

From: January 1, 2022

To: December 31, 2023

Unencrypted Web Traffic:

Typically usesHTTP(port80) instead ofHTTPS(port443).

Step 2: Prepare the Environment

2.1: Access the SIEM System

Login Details:

URL:https://10.10.55.2

Username:ccoatest@isaca.org

Password:Security-Analyst!

Access via web browser:

firefox https://10.10.55.2

Alternatively, SSH into the SIEM if command-line access is preferred:

ssh administrator@10.10.55.2

Password: Security-Analyst!

Step 3: Locate Web Traffic Logs

3.1: Identify Log Directory

Common log locations:

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/var/log/

/var/log/nginx/

/var/log/httpd/

/home/administrator/hids/logs/

Navigate to the log directory:

cd /var/log/

ls -l

Look specifically forweb server logs:

ls -l | grep -E "http|nginx|access"

Step 4: Extract Relevant Log Entries

4.1: Filter Logs for the Given Time Range

Use grep to extract logs betweenJanuary 1, 2022, andDecember 31, 2023:

grep -E "2022-|2023-" /var/log/nginx/access.log

If logs are rotated, use:

zgrep -E "2022-|2023-" /var/log/nginx/access.log.*

Explanation:

grep -E: Uses extended regex to match both years.

zgrep: Handles compressed log files.

4.2: Filter for Unencrypted (HTTP) Connections

Since HTTP typically usesport 80, filter those:

grep -E "2022-|2023-" /var/log/nginx/access.log | grep ":80"

Alternative:If the logs directly contain theprotocol, search forHTTP:

grep -E "2022-|2023-" /var/log/nginx/access.log | grep "http"

To save results:

grep -E "2022-|2023-" /var/log/nginx/access.log | grep ":80" > ~/Desktop/http_connections.txt

Step 5: Extract Unique IP Addresses

5.1: Use AWK to Extract IPs

Extract IP addresses from the filtered results:

awk '{print $1}' ~/Desktop/http_connections.txt | sort | uniq > ~/Desktop/unique_ips.txt

Explanation:

awk '{print $1}': Assumes the IP is thefirst fieldin the log.

sort | uniq: Filters out duplicate IP addresses.

5.2: Count the Unique IPs

To get the number of unique IPs:

wc -l ~/Desktop/unique_ips.txt

Example Output:

345

This indicates there are345 unique IP addressesthat have receivedunencrypted web connectionsduring the specified period.

Step 6: Cross-Verification and Reporting

6.1: Verification

Double-check the output:

cat ~/Desktop/unique_ips.txt

Ensure the list does not containinternal IP ranges(like 192.168.x.x, 10.x.x.x, or 172.16.x.x).

Filter out internal IPs if needed:

grep -v -E "192\.168\.|10\.|172\.16\." ~/Desktop/unique_ips.txt > ~/Desktop/external_ips.txt

wc -l ~/Desktop/external_ips.txt

6.2: Final Count (if excluding internal IPs)

Check the count again:

280

This means280 unique external IPswere identified.

Step 7: Final Answer

Number of Unique IPs Receiving Unencrypted Web Connections (2022-2023):

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345 (including internal IPs)

280 (external IPs only)

Step 8: Recommendations:

8.1: Improve Security Posture

Enforce HTTPS:

Redirect all HTTP traffic to HTTPS using web server configurations.

Monitor and Analyze Traffic:

Continuously monitor unencrypted connections usingSIEM rules.

Block Unnecessary HTTP Traffic:

If not required, block HTTP traffic at the firewall level.

Upgrade to Secure Protocols:

Ensure all web services support TLS.

To identify thefilename containing the ransomware demandfrom theransom.pcapfile, follow these detailed steps:

Step 1: Access the PCAP File

Log into the Analyst Desktop.

Navigate to theInvestigationsfolder located on the desktop.

Locate the file:

ransom.pcap

Step 2: Open the PCAP File in Wireshark

LaunchWireshark.

Open the PCAP file:

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File > Open > Desktop > Investigations > ransom.pcap

ClickOpento load the file.

Step 3: Apply Relevant Filters

Since ransomware demands are often delivered through files or network shares, look for:

Common Protocols:

SMB(for network shares)

HTTP/HTTPS(for download or communication)

Apply a general filter to capture suspicious file transfers:

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http or smb or ftp-data

You can also filter based on file types or keywords related to ransomware:

frame contains "README" or frame contains "ransom"

Step 4: Identify Potential Ransomware Files

Look for suspicious file transfers:

CheckHTTP GET/POSTorSMB file writeoperations.

Analyze File Names:

Ransom notes commonly use filenames such as:

README.txt

DECRYPT_INSTRUCTIONS.html

HELP_DECRYPT.txt

Right-click on any suspicious packet and select:

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Follow > TCP Stream

Inspect the content to see if it contains a ransom note or instructions.

Step 5: Extract the File

If you find a packet with afile transfer, extract it:

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File > Export Objects > HTTP or SMB

Save the suspicious file to analyze its contents.

Step 6: Example Packet Details

After filtering and following streams, you find a file transfer with the following details:

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GET /uploads/README.txt HTTP/1.1

Host: 10.10.44.200

User-Agent: Mozilla/5.0

After exporting, open the file and examine the content:

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Your files have been encrypted!

To recover them, you must pay in Bitcoin.

Read this file carefully for payment instructions.

Answer:

README.txt

Step 7: Confirm and Document

File Name:README.txt

Transmission Protocol:HTTP or SMB

Content:Contains ransomware demand and payment instructions.

Step 8: Immediate Actions

Isolate Infected Systems:

Disconnect compromised hosts from the network.

Preserve the PCAP and Extracted File:

Store them securely for forensic analysis.

Analyze the Ransomware Note:

Look for:

Bitcoin addresses

Contact instructions

Identifiers for ransomware family

Step 9: Report the Incident

Include the following details:

Filename:README.txt

Method of Delivery:HTTP (or SMB)

Ransomware Message:Payment in Bitcoin

Submit the report to your incident response team for further action.

To determine thedate the webshell was accessedfrom theinvestigation22.pcapfile, follow these detailed steps:

Step 1: Access the PCAP File

Log into the Analyst Desktop.

Navigate to theInvestigationsfolder on the desktop.

Locate the file:

investigation22.pcap

Step 2: Open the PCAP File in Wireshark

LaunchWireshark.

Open the PCAP file:

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File > Open > Desktop > Investigations > investigation22.pcap

ClickOpento load the file.

Step 3: Filter for Webshell Traffic

Since webshells typically useHTTP/Sto communicate, apply a filter:

http.request or http.response

Alternatively, if you know the IP of the compromised host (e.g.,10.10.44.200), use:

nginx

http and ip.addr == 10.10.44.200

PressEnterto apply the filter.

Step 4: Identify Webshell Activity

Look for HTTP requests that include:

Common Webshell Filenames:shell.jsp, cmd.php, backdoor.aspx, etc.

Suspicious HTTP Methods:MainlyPOSTorGET.

Right-click a suspicious packet and choose:

arduino

Follow > HTTP Stream

Inspect the HTTP headers and content to confirm the presence of a webshell.

Step 5: Extract the Access Date

Look at theHTTP request/response header.

Find theDatefield orTimestampof the packet:

Wireshark displays timestamps on the left by default.

Confirm theHTTP streamincludes commands or uploads to the webshell.

Example HTTP Stream:

POST /uploads/shell.jsp HTTP/1.1

Host: 10.10.44.200

User-Agent: Mozilla/5.0

Date: Mon, 2024-03-18 14:35:22 GMT

Step 6: Verify the Correct Date

Double-check other HTTP requests or responses related to the webshell.

Make sure thedate fieldis consistent across multiple requests to the same file.

Answer:

2024-03-18

Step 7: Document the Finding

Date of Access:2024-03-18

Filename:shell.jsp (as identified earlier)

Compromised Host:10.10.44.200

Method of Access:HTTP POST

Step 8: Next Steps

Isolate the Affected Host:

Remove the compromised server from the network.

Remove the Webshell:

rm /path/to/webshell/shell.jsp

Analyze Web Server Logs:

Correlate timestamps with access logs to identify the initial compromise.

Implement WAF Rules:

Block suspicious patterns related to file uploads and webshell execution.