Azure Run Command Forensics

Cloud forensics has become an essential aspect of cybersecurity, especially as organizations increasingly migrate their operations to the cloud. Azure Run Command, a feature in Microsoft Azure, allows administrators to remotely manage and troubleshoot VMs without needing direct access. However, this powerful tool can also be exploited by malicious actors if not properly monitored and secured. In this blog post, we will explore the forensic analysis of Azure Run Command activities, focusing on how to detect and investigate potential misuse.

What is Azure Run Command?

Azure Run Command enables users to run scripts or command-line actions on Azure VMs directly from the Azure portal or via Azure CLI. This functionality is incredibly useful for system administrators who need to perform routine maintenance, deploy applications, or troubleshoot issues without logging into each VM individually.

Forensic Importance of Azure Run Command

Understanding and monitoring the use of Azure Run Command is critical for cloud forensics for several reasons:

1. Remote Code Execution: Attackers can leverage Azure Run Command to execute malicious scripts on VMs.
2. Persistence Mechanism: Malicious actors can use it to establish persistence by installing backdoors or creating rogue user accounts.
3. Data Exfiltration: Scripts can be used to gather and exfiltrate sensitive data from VMs.
   
   

Key Artifacts and Logs

Forensic investigators need to be aware of the artifacts and logs generated by Azure Run Command to trace malicious activities effectively.

Azure Activity Logs

Azure Activity Logs provide a comprehensive record of actions taken on resources within your Azure environment. For Azure Run Command, look for the following:

• Invoke Run Command: This log entry will indicate that a Run Command action was initiated. It includes details such as the timestamp, user identity, and the specific command executed.
• Resource Group and VM Name: Identifying the resource group and VM affected is crucial for narrowing down the scope of the investigation.

VM Extension Logs

Azure VMs create extension logs that can be invaluable during forensic analysis:

• Location: These logs are typically located in the /var/log/azure and /var/lib/waagent/run-command/download/. directories on Linux VMs or C:\WindowsAzure\Logs\Plugins on Windows VMs.
• Content: Extension logs include details about the scripts executed, their output, and any errors encountered. This can help reconstruct the sequence of events and determine the impact of malicious scripts.

For additional details on forensic artifact locations, see this excellent blog post from Mandiant.

Investigative Techniques

When conducting a forensic investigation involving Azure Run Command, the following steps are recommended:

1. Collecting Logs

Gather Azure Activity Logs and VM extension logs for the period of interest. Use Azure CLI or PowerShell scripts to automate the collection process for multiple VMs.

2. Analyzing Command Execution

Review the commands executed via Azure Run Command. Look for anomalies such as:

• Unusual Commands: Commands that do not align with normal administrative activities.
• Script Content: Scripts that include data exfiltration commands, user account creation, or downloading of additional malware.

3. Cross-Referencing with Other Logs

Correlate Azure Run Command activities with other logs such as network logs, application logs, and security logs. This can help identify lateral movement, data exfiltration, or further exploitation attempts.

Example: Detecting Malicious Use of Azure Run Command

For example, say an organization has detected unusual network traffic originating from one of their Azure VMs.

Here are the steps you would take in such an investigation:

1. Identified the Compromised VM: Using Azure Activity Logs, the specific VM where the command was executed was identified.
2. Retrieved VM Extension Logs: Analyzed the extension logs to confirm the commands executed and the scripts involved.
3. Correlated Network Traffic: Matched the timestamps of the command execution with the network logs to trace the data flow and confirm the exfiltration route.
4. Mitigated the Threat: Disabled the compromised account, removed the malicious scripts, and implemented stricter access controls.

Azure Run Command is a powerful and convenient tool for managing Azure VMs, but it is also equally powerful and useful for attackers. FInvestigators must understand how to track and analyze the use of this feature to respond to security incidents. By utilizing Azure Activity Logs and VM extension logs, investigators can piece together the actions taken by attackers and mitigate potential threats swiftly.

For more details, please see:

- https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/windows-azure-guest-agent

- https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/debug-customscriptextension-runcommand-scripts

- https://cloud.google.com/blog/topics/threat-intelligence/azure-run-command-dummies