Using KQL to Track System Vulnerabilities

Leveraging KQL for Enhanced Security Monitoring

System vulnerabilities are a persistent concern in the evolving landscape of cybersecurity. Outdated software, misconfigured systems, and improper administrative access are prime targets for exploitation by malicious actors. Enter KQL, or Kusto Query Language, a powerful tool for data analysis and security monitoring within platforms like Azure Monitor and Microsoft Sentinel. This blog explores how KQL can be used to identify system vulnerabilities, detect privilege escalation attempts, and enhance your overall security posture.

Tracking Outdated Software and Configurations

One of the most common vulnerabilities in a system is outdated software or configurations. These weaknesses often serve as entry points for attackers, making it crucial to identify and address them promptly.

Why Outdated Software Matters

Outdated software lacks the latest security patches, exposing systems to known vulnerabilities. Configuration issues, such as the use of weak encryption methods or default settings, further amplify the risk. Regular audits and proactive monitoring are vital to mitigate these threats.

KQL Queries for Identifying Outdated Software

Using KQL, you can analyze logs and telemetry data to pinpoint systems running outdated versions of software or possessing misconfigurations. Here’s a sample query:

DeviceSoftwareInventory
| where SoftwareVersion !contains "latest"
| summarize OutdatedCount = count() by DeviceName
| project DeviceName, OutdatedCount

This query filters devices based on software versions and provides a summary of systems that require updates. The use of fields such as DeviceSoftwareInventory depends on your specific environment and data schema, so adapting the query to your setup is essential.

Detecting Vulnerable Configurations

KQL also enables you to search for configuration-related issues. For instance, you can detect systems using outdated encryption algorithms:

Query:

DeviceFileCertificateInfo
| where EncryptionType == 'SHA1'
| summarize VulnerableDevices = count() by DeviceName
| project DeviceName, VulnerableDevices

Such queries help identify devices that require immediate configuration changes to align with modern security standards.

Detecting Privilege Escalation and Improper Administrative Access

Privilege escalation is a common attack vector that allows attackers to gain unauthorized access to critical system components. Detecting these attempts is crucial to prevent breaches.

Understanding Privilege Escalation Risks

Privilege escalation exploits can result from improper administrative access, exploitation of bugs, or lateral movement across networked systems. Monitoring access patterns and flagging anomalies are key to managing these risks.

KQL Query for Privilege Escalation Attempts

KQL can be harnessed to analyze user activity and detect suspicious patterns indicative of privilege escalation. Consider the following query:

SecurityEvent
| where EventID == 4672
| extend UserActivity = strcat(SubjectUserName, ': ', Activity)
| summarize EscalationAttempts = count() by UserActivity
| project UserActivity, EscalationAttempts

This query identifies events where special privileges were assigned to accounts, flagging potential privilege escalation attempts for further investigation.

Detecting Improper Administrative Access

Sometimes, administrative privileges may be improperly assigned to users, elevating their access rights beyond necessity. To detect such cases, try this KQL query:

SecurityEvent
| where EventID == 4728 or EventID == 4732
| extend AdminChanges = strcat(SubjectUserName, ': ', TargetAccount)
| summarize ChangesCount = count() by AdminChanges
| project AdminChanges, ChangesCount

This query monitors changes to administrative groups and flags instances where users have been added or removed, allowing you to verify the legitimacy of such modifications.

TLDR

KQL empowers security teams by providing robust insights into system vulnerabilities and suspicious activities. By crafting precise queries tailored to your environment, you can proactively identify outdated software, misconfigurations, and improper privilege escalations. Integrating these practices into your security protocols ensures you stay ahead of potential threats, enhancing your organization's resilience against cyberattacks.

Next Steps

1. Regularly audit system logs using KQL queries.

2. Customize queries to address your organization’s specific vulnerabilities.

3. Automate alert generation for critical findings to ensure swift responses.

Using KQL is not just about detecting vulnerabilities—it’s about fostering a proactive, data-driven approach to cybersecurity. Start leveraging its power today to safeguard your systems effectively.

Learn more

• Must Learn KQL - the blog series, the book, the completion certificate, the video channel, the merch store, the workshop, and much more... https://aka.ms/MustLearnKQL

• The Definitive Guide to KQL: Using Kusto Query Language for operations, defending, and threat hunting https://amzn.to/42JRsCL