Free CCOA Isaca Updates

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

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 determine the host IP of the machine vulnerable toCVE-2021-22145usingGreenbone Vulnerability Manager (GVM), follow these detailed steps:

Step 1: Access Greenbone Vulnerability Manager

OpenFirefoxon your system.

Go to the GVM login page:

URL:

Enter the credentials:

Username: admin

Password: Secure-gvm!

ClickLoginto access the dashboard.

Step 2: Navigate to Scan Reports

Once logged in, locate the"Scans"menu on the left panel.

Click on"Reports"under the"Scans"section to view the list of completed vulnerability scans.

Step 3: Identify the Most Recent Scan

Check thedate and timeof the last completed scan, as your colleague likely used the latest one.

Click on theReport NameorDateto open the detailed scan results.

Step 4: Filter for CVE-2021-22145

In the report view, locate the"Search"or"Filter"box at the top.

Enter the CVE identifier:

CVE-2021-22145

PressEnterto filter the vulnerabilities.

Step 5: Analyze the Results

The system will display any host(s) affected byCVE-2021-22145.

The details will typically include:

Host IP Address

Vulnerability Name

Severity Level

Vulnerability Details

Example Display:

Host IP

Vulnerability ID

CVE

Severity

192.168.1.100

SomeVulnName

CVE-2021-22145

High

Step 6: Verify the Vulnerability

Click on the host IP to see thedetailed vulnerability description.

Check for the following:

Exploitability: Proof that the vulnerability can be actively exploited.

Description and Impact: Details about the vulnerability and its potential impact.

Fixes/Recommendations: Suggested mitigations or patches.

Step 7: Note the Vulnerable Host IP

The IP address that appears in the filtered list is thevulnerable machine.

Example Answer:

The host IP of the machine vulnerable to CVE-2021-22145 is: 192.168.1.100

Step 8: Take Immediate Actions

Isolate the affected machineto prevent exploitation.

Patch or updatethe software affected by CVE-2021-22145.

Perform a quick re-scanto ensure that the vulnerability has been mitigated.

Step 9: Generate a Report for Documentation

Export the filtered scan results as aPDForHTMLfrom the GVM.

Include:

Host IP

CVE ID

Severity and Risk Level

Remediation Steps

Background on CVE-2021-22145:

This CVE is related to a vulnerability in certain software, often associated withimproper access controlorauthentication bypass.

Attackers can exploit this to gain unauthorized access or escalate privileges.

To decode theCommand and Control (C2) hostfrom thepcap_artifact5.txtfile, follow these detailed steps:

Step 1: Access the File

Log into the Analyst Desktop.

Navigate to theDesktopand locate the file:

pcap_artifact5.txt

Open the file using a text editor:

OnWindows:

nginx

notepad pcap_artifact5.txt

OnLinux:

cat ~/Desktop/pcap_artifact5.txt

Step 2: Examine the File Contents

Check the contents to identify the encoding format. Typical encodings used for C2 communication include:

Base64

Hexadecimal

URL Encoding

ROT13

Example File Content (Base64 format):

nginx

aHR0cDovLzEwLjEwLjQ0LjIwMDo4MDgwL2NvbW1hbmQucGhw

Step 3: Decode the Contents

Method 1: Using PowerShell (Windows)

OpenPowerShelland decode:

powershell

$encoded = Get-Content "C:\Users\\Desktop\pcap_artifact5.txt"

[System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($encoded))

This will print the decoded content directly.

Method 2: Using Linux

Usebase64 decoding:

base64 -d ~/Desktop/pcap_artifact5.txt

If the content ishexadecimal, convert it as follows:

xxd -r -p ~/Desktop/pcap_artifact5.txt

If it appearsURL encoded, use:

echo -e $(cat ~/Desktop/pcap_artifact5.txt | sed 's/%/\\x/g')

Step 4: Analyze the Decoded Output

If the output appears like a URL or an IP address, that is likely theC2 host.

Example Decoded Output:

arduino

TheC2 hostis:

10.10.44.200

Step 5: Cross-Verify the C2 Host

OpenWiresharkand load the relevant PCAP file to cross-check the IP:

mathematica

File > Open > Desktop > Investigations > ransom.pcap

Filter for C2 traffic:

ini

ip.addr == 10.10.44.200

Validate the C2 host IP address through network traffic patterns.

Answer:

10.10.44.200

Step 6: Document the Finding

Record the following details:

Decoded C2 Host:10.10.44.200

Source File:pcap_artifact5.txt

Decoding Method:Base64 (or the identified method)

Step 7: Next Steps

Threat Mitigation:

Block the IP address10.10.44.200at the firewall.

Conduct anetwork-wide searchto identify any communications with the C2 server.

Further Analysis:

Check other PCAP files for similar traffic patterns.

Perform adeep packet inspection (DPI)to identify malicious data exfiltration.

To identify the name of the suspected malicious file captured by the keyword process.executable at11:04 PMonAugust 19, 2024, follow these detailed steps:

Step 1: Access the Alert Bulletin

Locate the alert file:

Access thealerts folderon your system.

Look for the file named:

Open the file:

Use a PDF reader to examine the contents.

Step 2: Understand the Alert Context

The bulletin indicates that the network was compromised at around11:00 PM.

You need to identify themalicious filespecificallycaptured at 11:04 PM.

Step 3: Access System Logs

Use yourSIEMorlog management systemto examine recent logs.

Filter the logs to narrow down the events:

Time Frame:August 19, 2024, from11:00 PM to 11:10 PM.

Keyword:process.executable.

Example SIEM Query:

index=system_logs

| search "process.executable"

| where _time between "2024-08-19T23:04:00" and "2024-08-19T23:05:00"

| table _time, process_name, executable_path, hash

Step 4: Analyze Log Entries

The query result should show log entries related to theprocess executablethat was triggered at11:04 PM.

Focus on entries that:

Appear unusual or suspicious.

Match known indicators from thealert bulletin (alert_33.pdf).

Example Log Output:

_time process_name executable_path hash

2024-08-19T23:04 evil.exe C:\Users\Public\evil.exe 4d5e6f...

Step 5: Cross-Reference with Known Threats

Check the hash of the executable file against:

VirusTotalor internal threat intelligence databases.

Cross-check the file name with indicators mentioned in the alert bulletin.

Step 6: Final Confirmation

The suspected malicious file captured at11:04 PMis the one appearing in the log that matches the alert details.

The name of the suspected malicious file captured by keyword process.executable at 11:04 PM is: evil.exe

Step 7: Take Immediate Remediation Actions

Isolate the affected hostto prevent further damage.

Quarantine the malicious filefor analysis.

Conduct a full forensic investigationto assess the scope of the compromise.

Update threat signaturesand indicators across the environment.

Step 8: Report and Document

Document the incident, including:

Time of detection:11:04 PM on August 19, 2024.

Malicious file name:evil.exe.

Location:C:\Users\Public\evil.exe.

Generate an incident reportfor further investigation.