Lab - Investigating An Attack On A Windows Host

Diving deep into the world of cybersecurity incident response requires a solid understanding of how to investigate attacks on Windows hosts. The ability to meticulously analyze compromised systems is crucial for identifying the root cause, scope, and impact of an attack, ultimately enabling effective remediation and prevention strategies.

Setting the Stage: A Simulated Attack Scenario

Imagine a scenario: a user reports suspicious activity on their Windows workstation. Files are missing, applications are behaving erratically, and the system seems sluggish. This triggers a cybersecurity incident response process, and your mission is to investigate the attack.

Before jumping into the technical aspects, let’s define the scope and objectives of our investigation:

• Objective: Determine the nature of the attack, identify the attacker's actions, assess the impact on the system, and recommend remediation steps.
• Scope: Focus on the compromised Windows host and any network connections originating from or directed towards it.

Tools of the Trade: Essential Resources for Windows Host Investigation

A well-equipped investigator relies on a diverse toolkit. Here are some essential resources for investigating attacks on Windows hosts:

• Sysinternals Suite: A collection of powerful tools from Microsoft, including Process Explorer, Process Monitor, Autoruns, and more, used for in-depth system analysis.
• Windows Event Logs: Comprehensive records of system events, application activity, security events, and more. A goldmine for identifying malicious activities.
• Network Monitoring Tools: Wireshark or TCPView to capture and analyze network traffic, revealing suspicious connections and data exfiltration attempts.
• Anti-Malware Software: Updated antivirus and anti-malware solutions to scan for and remove malicious software.
• Memory Forensics Tools: Tools like Volatility Framework can analyze system memory dumps to uncover hidden processes, injected code, and other artifacts.
• Disk Imaging Tools: Tools to create a forensic image of the hard drive, preserving the evidence in its original state for analysis.

Step-by-Step Investigation: Unraveling the Attack

Now, let’s break down the investigation into a series of manageable steps:

1. Initial Assessment and Evidence Collection

The first step is to gather as much information as possible without altering the system significantly. This includes:

• Interviewing the User: Ask the user about their activities leading up to the incident. What websites did they visit? What emails did they open? What applications were they running?
• System Snapshot: Take a snapshot of the system's current state. Note the date and time, running processes, network connections, and any error messages.
• Isolate the System: Disconnect the system from the network to prevent further spread of the attack.
• Create a Forensic Image: Create a forensic image of the hard drive using a reliable disk imaging tool. This ensures that you have a pristine copy of the data for analysis.
• Document Everything: Meticulously document every step of the investigation, including the tools used, commands executed, and findings. This is crucial for maintaining the integrity of the investigation and for future reference.

2. Analyzing Windows Event Logs

Windows Event Logs are a treasure trove of information. They record a wide range of events, including:

• Security Events: Login attempts (successful and failed), account management activities, privilege escalations, and security policy changes.
• Application Events: Application errors, crashes, and warnings.
• System Events: System startup and shutdown, hardware errors, and driver issues.

To analyze the event logs:

• Open Event Viewer: Type "Event Viewer" in the Windows search bar and open the application.
• Filter Events: Filter events by date and time, event ID, user account, and source to narrow down the search. Focus on security events and application errors that occurred around the time of the reported incident.
• Look for Suspicious Activity:
  • Failed Login Attempts: Multiple failed login attempts from different IP addresses could indicate a brute-force attack.
  • Account Lockouts: Account lockouts can be a sign of attackers trying to guess passwords.
  • New User Accounts: Creation of new user accounts with administrative privileges without authorization.
  • Security Policy Changes: Modifications to security policies that weaken system security.
  • Application Errors: Application crashes or errors that might indicate exploitation of vulnerabilities.
  • Unusual Process Creation: Processes starting from unusual locations or with suspicious command-line arguments.
• Correlate Events: Correlate events from different logs to build a timeline of the attack. For example, a failed login attempt followed by a successful login with the same account might indicate a successful password cracking attempt.
• Use PowerShell: PowerShell can be used to query and filter event logs more efficiently. For example:

  Get-WinEvent -LogName Security -MaxEvents 100 | Where-Object {$_.ID -eq 4625} | Format-Table -AutoSize
  

  This command retrieves the last 100 security events with ID 4625 (failed login attempts) and displays them in a table.

3. Examining Running Processes with Process Explorer

Process Explorer is a powerful tool for examining running processes. It provides detailed information about each process, including its CPU usage, memory usage, handles, and loaded modules.

To use Process Explorer:

• Download and Run Process Explorer: Download Process Explorer from the Microsoft website and run it.
• Identify Suspicious Processes: Look for processes with:
  • Unusual Names: Processes with names that don't match any known applications.
  • High CPU or Memory Usage: Processes consuming excessive CPU or memory without a clear reason.
  • Unknown Publisher: Processes with no or an unknown publisher.
  • Processes Running from Temporary Directories: Processes running from temporary directories like %TEMP% or %AppData%.
  • Processes with Suspicious Network Connections: Processes with connections to suspicious IP addresses or domains.
• Analyze Process Details:
  • View Process Properties: Right-click on a process and select "Properties" to view detailed information about the process, including its path, command-line arguments, and user account.
  • Check Process Image: Verify the process image's digital signature to ensure it is signed by a trusted publisher.
  • Inspect Loaded Modules: Examine the modules loaded by the process to identify any malicious or suspicious DLLs.
  • View Process Threads: Analyze the threads running within the process to identify any unusual activity.
• Kill Suspicious Processes (with Caution): If you identify a malicious process, you can kill it using Process Explorer. However, be careful when killing processes, as it might disrupt system functionality.

4. Analyzing Startup Programs with Autoruns

Autoruns is a tool that displays all the programs that are configured to run automatically when the system starts up or when a user logs in. Malware often uses autorun entries to ensure that it persists across reboots.

To use Autoruns:

• Download and Run Autoruns: Download Autoruns from the Microsoft website and run it.
• Review Autorun Entries: Examine the list of autorun entries for any suspicious or unknown programs.
• Look for Entries in Unusual Locations: Pay attention to entries located in unusual registry keys or directories.
• Verify Digital Signatures: Verify the digital signatures of the autorun entries to ensure they are signed by trusted publishers.
• Disable or Delete Suspicious Entries: Disable or delete any suspicious autorun entries. This will prevent the program from running automatically.
• Use Online Lookups: Right-click on an entry and select "Search Online" to search for information about the program online.

5. Monitoring File System Activity with Process Monitor

Process Monitor is a powerful tool that monitors file system, registry, and process activity in real-time. It can be used to identify malicious software that is creating, modifying, or deleting files or registry keys.

To use Process Monitor:

• Download and Run Process Monitor: Download Process Monitor from the Microsoft website and run it.
• Configure Filters: Configure filters to focus on specific processes, file paths, registry keys, or event types. This will reduce the amount of noise and make it easier to identify suspicious activity.
• Monitor File System Activity: Monitor file system activity for:
  • Creation of Executable Files in Unusual Locations: Creation of executable files in temporary directories or other unusual locations.
  • Modification of System Files: Modification of critical system files like hosts file or system32 directory.
  • Deletion of Log Files: Deletion of log files to cover up tracks.
  • Creation of Hidden Files: Creation of hidden files or directories.
• Monitor Registry Activity: Monitor registry activity for:
  • Modification of Autorun Keys: Modification of registry keys that control startup programs.
  • Creation of New Registry Keys: Creation of new registry keys with suspicious names or values.
  • Deletion of Registry Keys: Deletion of registry keys related to security settings.
• Analyze Process Activity: Analyze process activity for:
  • Processes Accessing Sensitive Files: Processes accessing sensitive files like password databases or cryptographic keys.
  • Processes Making Network Connections: Processes making network connections to suspicious IP addresses or domains.
• Save the Log: Save the Process Monitor log for later analysis.

6. Network Traffic Analysis with Wireshark

Wireshark is a network protocol analyzer that can capture and analyze network traffic. It can be used to identify suspicious network connections, data exfiltration attempts, and other malicious network activity.

To use Wireshark:

• Download and Install Wireshark: Download and install Wireshark from the Wireshark website.
• Capture Network Traffic: Start Wireshark and select the network interface to capture traffic from.
• Filter Network Traffic: Use filters to focus on specific protocols, IP addresses, or ports. For example, use the filter http to capture HTTP traffic or ip.addr == 192.168.1.100 to capture traffic to or from the IP address 192.168.1.100.
• Analyze Network Traffic:
  • Look for Suspicious Connections: Identify connections to suspicious IP addresses or domains. Use online resources like VirusTotal to check the reputation of IP addresses and domains.
  • Analyze Data Exfiltration Attempts: Look for patterns of data exfiltration, such as large amounts of data being sent to an external IP address.
  • Identify Command and Control (C&C) Communication: Look for communication with known C&C servers.
  • Examine HTTP Traffic: Analyze HTTP traffic for suspicious URLs, user-agent strings, or data being sent in clear text.
  • Analyze DNS Traffic: Analyze DNS traffic for requests to suspicious domains.
• Save the Capture File: Save the Wireshark capture file for later analysis.

7. Memory Forensics with Volatility Framework

Memory forensics involves analyzing a memory dump of a system to uncover hidden processes, injected code, and other artifacts. The Volatility Framework is a powerful tool for performing memory forensics.

To use Volatility Framework:

• Acquire a Memory Dump: Acquire a memory dump of the compromised system using a tool like FTK Imager or DumpIt.
• Install Volatility Framework: Install the Volatility Framework on a separate analysis system.
• Determine the System Profile: Determine the system profile of the memory dump using the imageinfo plugin.

  vol.py -f memory.dump imageinfo
  

• Analyze Running Processes: Analyze the running processes using the pslist or psscan plugins.

  vol.py -f memory.dump --profile=Win7SP1x64 pslist
  

• Identify Hidden Processes: Use the psxview plugin to identify hidden processes.

  vol.py -f memory.dump --profile=Win7SP1x64 psxview
  

• Extract Executable Files: Extract executable files from memory using the procdump plugin.

  vol.py -f memory.dump --profile=Win7SP1x64 procdump -p  -D ./
  

• Analyze Network Connections: Analyze network connections using the netscan plugin.

  vol.py -f memory.dump --profile=Win7SP1x64 netscan
  

• Look for Code Injection: Look for code injection using the malfind plugin.

  vol.py -f memory.dump --profile=Win7SP1x64 malfind
  

8. Malware Analysis

If you suspect that the system is infected with malware, you need to analyze the malware to understand its functionality and identify its indicators of compromise (IOCs).

• Static Analysis:
  • File Hashing: Calculate the hash of the malware file and use online resources like VirusTotal to check if the file is known malware.
  • Strings Analysis: Extract strings from the malware file to identify readable text, URLs, or other indicators.
  • PE Header Analysis: Analyze the PE header of the malware file to determine its compile time, entry point, and other information.
  • Disassembly: Disassemble the malware file using a disassembler like IDA Pro or Ghidra to understand its code.
• Dynamic Analysis:
  • Sandbox Analysis: Run the malware in a sandbox environment to observe its behavior.
  • Network Analysis: Monitor the malware's network activity to identify its C&C server and data exfiltration attempts.
  • System Monitoring: Monitor the malware's file system and registry activity to identify its IOCs.

9. Reporting and Remediation

Once you have completed the investigation, you need to create a report that summarizes your findings and recommends remediation steps.

• Report:
  • Executive Summary: A brief overview of the incident and its impact.
  • Timeline of Events: A chronological order of the events that occurred during the attack.
  • Technical Details: Detailed information about the malware, the attacker's techniques, and the compromised systems.
  • Indicators of Compromise (IOCs): A list of IOCs that can be used to detect the malware on other systems.
  • Remediation Steps: Recommendations for removing the malware and preventing future attacks.
• Remediation:
  • Isolate the System: Keep the compromised system isolated from the network until it is cleaned.
  • Remove the Malware: Remove the malware using anti-malware software or manual removal techniques.
  • Patch Vulnerabilities: Patch any vulnerabilities that were exploited by the attacker.
  • Reset Passwords: Reset passwords for all accounts that may have been compromised.
  • Monitor Systems: Monitor systems for any signs of reinfection.
  • Implement Security Measures: Implement additional security measures to prevent future attacks, such as multi-factor authentication, intrusion detection systems, and security awareness training.

Deep Dive: Understanding Common Attack Vectors

To effectively investigate an attack, it's crucial to understand common attack vectors targeting Windows hosts:

• Phishing: Attackers use deceptive emails or websites to trick users into revealing their credentials or downloading malware.
• Drive-by Downloads: Attackers compromise websites and inject malicious code that automatically downloads malware onto visitors' computers.
• Exploitation of Software Vulnerabilities: Attackers exploit vulnerabilities in software applications or the operating system to gain unauthorized access to the system.
• Malvertising: Attackers use malicious advertisements to spread malware through online advertising networks.
• Ransomware: Attackers encrypt the victim's files and demand a ransom payment for their decryption.
• Supply Chain Attacks: Attackers compromise software vendors or third-party suppliers to distribute malware to a wide range of victims.

Advanced Techniques and Considerations

Beyond the basic steps, consider these advanced techniques and considerations:

• Timeline Analysis: Creating a detailed timeline of events, correlating data from different sources, can reveal the attacker's actions and the sequence of events.
• Rootkit Detection: Rootkits are designed to hide their presence from the operating system. Use specialized tools like Rootkit Revealer or GMER to detect rootkits.
• Log Correlation: Correlate logs from different systems, such as firewalls, intrusion detection systems, and servers, to gain a broader view of the attack.
• Threat Intelligence: Leverage threat intelligence feeds to identify known malicious IP addresses, domains, and malware signatures.

The Human Element: Social Engineering Awareness

Never underestimate the power of social engineering. Educate users about phishing scams, suspicious emails, and the importance of strong passwords. A well-trained user base is a crucial line of defense against cyberattacks.

Continuous Improvement: Learning from Each Incident

Every incident is a learning opportunity. After resolving an attack, conduct a post-incident review to identify areas for improvement in your security posture and incident response process.

Conclusion: Mastering the Art of Windows Host Investigation

Investigating attacks on Windows hosts requires a combination of technical skills, analytical thinking, and a methodical approach. By mastering the tools and techniques described in this article, you can effectively analyze compromised systems, identify the root cause of attacks, and implement effective remediation strategies. Remember that cybersecurity is a constantly evolving field, so continuous learning and adaptation are essential for staying ahead of the attackers.