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Microsoft Sentinel SOC 101: How to Detect and Mitigate Phishing Attacks with Microsoft Sentinel
Hook, Line, Sinker
Phishing attacks have become increasingly prevalent and pose significant risks to individuals and organizations alike. Cybercriminals are constantly evolving their tactics, making it crucial for security professionals to stay ahead of the game. One effective approach to combatting phishing attacks is to leverage the power of Microsoft Sentinel, a cloud-native security information and event management (SIEM) solution. In this article, we will explore the steps to detect and mitigate phishing attacks using Microsoft Sentinel. From understanding the threat landscape to implementing proactive measures, this article will equip you with the knowledge and tools to safeguard your organization against phishing threats.
Introduction to Phishing Attacks
The Rising Threat of Phishing Attacks
Phishing attacks have become a pervasive and persistent threat in recent years. These attacks involve cybercriminals masquerading as trustworthy entities to trick individuals into divulging sensitive information or performing actions that compromise security. Phishing attacks can take various forms, including email phishing, smishing (SMS phishing), and vishing (voice phishing). The sophistication of phishing attacks continues to increase, making them harder to detect and resist.
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Why Phishing Attacks are Successful
Phishing attacks are highly effective for several reasons. Firstly, they exploit human vulnerabilities, targeting individuals' trust, curiosity, and desire for convenience. Phishing emails often appear legitimate, using social engineering techniques to deceive recipients. Additionally, the sheer volume of phishing attacks makes it challenging for organizations to identify and respond to every instance. Cybercriminals often take advantage of current events and trends to enhance the authenticity of their attacks. The financial gain for attackers is substantial, as successful phishing attacks can lead to identity theft, financial fraud, or unauthorized access to sensitive data.
The "Defense in Depth" Approach
Layered Security for Comprehensive Protection
To effectively combat phishing attacks, organizations need to adopt a "defense in depth" approach. This approach involves deploying multiple layers of security measures that address various stages of the attack chain. By implementing a combination of preventive, detective, and responsive security controls, organizations can significantly reduce their vulnerability to phishing attacks. The key is to have a comprehensive security strategy that encompasses user education, email filtering, endpoint protection, network security, and incident response.
Addressing Phishing Across the Attack Chain
Phishing attacks typically involve several stages, from the initial delivery of a malicious email to the execution of the final payload. To mitigate the risks associated with phishing attacks, organizations need to address each stage of the attack chain. This includes implementing measures such as:
User education and awareness programs to help individuals recognize and report phishing emails.
Robust email filtering solutions to identify and block phishing emails before they reach users' inboxes.
Endpoint protection solutions that can detect and block malicious attachments or URLs.
Network security controls, such as firewalls and intrusion detection systems, to monitor and prevent unauthorized access.
Incident response plans and procedures to enable organizations to respond effectively in the event of a phishing attack.
By implementing security measures at each stage of the attack chain, organizations can significantly reduce their vulnerability to phishing attacks and minimize the potential impact of successful attacks.
Proactive Threat Hunting with Microsoft Sentinel
Leveraging KQL for Threat Hunting
Microsoft Sentinel provides security professionals with a powerful toolset for proactive threat hunting. Key to this capability is the use of Kusto Query Language (KQL), a powerful query language that allows analysts to search and analyze large volumes of data quickly. By leveraging KQL, security teams can identify potential phishing threats by searching for patterns and indicators of compromise (IoCs) within their data.
EXAMPLE: This query determines emails sent by top malicious/bad IP addresses.
let cutoff = 5; EmailEvents | where ThreatTypes has "Malware" or ThreatTypes has "Phish" | summarize count() by SenderIPv4 | where count_ > cutoff // Arbitrary cutoff, increase or decrease as needed | join EmailEvents on SenderIPv4 | where DeliveryAction =~ "Delivered"
Identifying Emerging Phishing Campaigns
Phishing campaigns are constantly evolving, with cybercriminals employing new techniques and tactics to bypass security measures. To stay ahead of these threats, security teams can use Microsoft Sentinel to proactively hunt for emerging phishing campaigns. By monitoring and analyzing data from various sources, such as Microsoft 365 Threat Protection (MTP), Defender for Office, and Microsoft Cloud App Security (MCAS), analysts can identify patterns and behaviors associated with phishing attacks.
Integrating Microsoft 365 Threat Protection
Utilizing Microsoft 365 Threat Protection (MTP)
Microsoft 365 Threat Protection (MTP) is a comprehensive security solution that combines the power of multiple Microsoft security products. It includes features such as Office 365 Advanced Threat Protection and Windows Defender. By integrating MTP with Microsoft Sentinel, organizations can benefit from enhanced threat detection and response capabilities.
Exploring Threat Hunting Capabilities in MTP
Within MTP, security analysts can leverage advanced hunting capabilities to proactively search for and investigate potential phishing threats. Advanced hunting allows analysts to query and analyze vast amounts of security-related data, helping them identify patterns, trends, and IoCs associated with phishing attacks. By combining this data with the power of KQL, analysts can gain deeper insights into emerging phishing campaigns and take proactive steps to mitigate the risks.
The Power of Microsoft Sentinel
Understanding the Role of Microsoft Sentinel
Microsoft Sentinel is a cloud-native SIEM solution that enables organizations to collect, analyze, and visualize security data from various sources. It provides a centralized platform for managing security incidents, conducting investigations, and implementing response actions. By integrating with Microsoft Sentinel, organizations can leverage the power of the cloud to enhance their threat detection and response capabilities.
Integration with Microsoft 365 Threat Protection
One of the key benefits of integrating with Microsoft Sentinel is the seamless integration with Microsoft 365 Threat Protection. This integration allows security teams to correlate and analyze data from MTP alongside other security data sources, enabling a more comprehensive and holistic view of potential phishing threats. By centralizing and correlating data from multiple sources, organizations can detect and respond to phishing attacks more effectively.
Building a Security Orchestration, Automation, and Response (SOAR) System
Implementing Security Automation with Logic Apps
To enhance the efficiency and effectiveness of phishing attack response, organizations can implement security orchestration, automation, and response (SOAR) systems. Microsoft Sentinel provides integration with Azure Logic Apps, allowing organizations to automate and streamline their phishing attack response processes. Logic Apps enable organizations to create workflows that automate various security tasks, such as analyzing suspicious emails, blocking malicious URLs, and generating incident reports.
Creating an End-to-End Phishing Attack Response System
By combining the power of Microsoft Sentinel and Logic Apps, organizations can create an end-to-end phishing attack response system. This system can automatically detect and analyze potential phishing emails, assess the risk level, and trigger appropriate response actions based on predefined rules and workflows. Examples of response actions include quarantining suspicious emails, blocking malicious URLs, and notifying security teams for further investigation.
Investigating Phishing Emails with Kusto Query Language (KQL)
Analyzing URLs in Phishing Emails
Kusto Query Language (KQL) provides a powerful tool for investigating phishing emails. Analysts can use KQL queries to search for specific URLs within email events and correlate them with known phishing URLs from external threat intelligence sources. By identifying and analyzing URLs that match known phishing URLs, organizations can proactively identify potential phishing attacks and take appropriate action to mitigate the risks.
Extracting Relevant Information from Email Events
In addition to analyzing URLs, KQL queries can also extract relevant information from email events, such as sender information, subject lines, attachment counts, and timestamps. By summarizing and analyzing this information, organizations can gain insights into the characteristics and patterns of phishing emails. This information can help in identifying trends, improving detection algorithms, and guiding incident response efforts.
Taking Action Against Phishing Attacks
Automating Responses for High-Confidence Phishing Attacks
Organizations can further enhance their phishing attack response capabilities by automating response actions for high-confidence phishing attacks. By leveraging the power of Microsoft Sentinel and Logic Apps, security teams can create automated workflows that trigger predefined response actions based on specific criteria. Examples of automated response actions include blocking malicious URLs, quarantining suspicious emails, and notifying security teams for further investigation.
Reporting Suspicious Emails to the NCSC
To combat phishing attacks effectively, organizations can report suspicious emails to external authorities such as the National Cyber Security Centre (NCSC). Microsoft Sentinel can be integrated with the Suspicious Email Reporting Service (SERS) provided by the NCSC, enabling organizations to automatically report identified phishing emails. By sharing information with external authorities, organizations contribute to a broader cybersecurity ecosystem, helping to protect others from similar attacks.
Enhancing Email Security with Microsoft Sentinel
Establishing Custom Logs for Email Events
Microsoft Sentinel allows organizations to establish custom logs for email events, providing a centralized repository for storing and analyzing email-related data. By configuring custom logs, organizations can capture and analyze email events at a granular level, enabling more effective threat detection and incident response. Custom logs can be tailored to capture specific attributes and metadata of emails, such as sender information, recipient information, subject lines, and attachment details.
Parsing Data to Facilitate Investigation
Once email events are captured in custom logs, organizations can parse and analyze the data to facilitate investigation and response efforts. By extracting relevant information from email events, such as sender addresses, recipient addresses, and attachment details, organizations can gain insights into the characteristics and patterns of phishing attacks. This information can be used to develop more robust detection algorithms, improve incident response procedures, and enhance overall email security.
Advanced Investigation Techniques
Deep Dive Investigations with KQL
When investigating potential phishing attacks, security teams can perform deep dive investigations using Kusto Query Language (KQL). By combining KQL queries with advanced hunting capabilities, organizations can search and analyze large volumes of security-related data to identify potential phishing threats. Deep dive investigations can uncover hidden patterns, trends, and IoCs, enabling organizations to proactively detect and respond to phishing attacks.
EXAMPLE: This query helps surface phishing campaigns associated with Appspot abuse. These emails frequently contain phishing links that utilize the recipients' own email address as a unique identifier in the URI.
EmailUrlInfo // Detect URLs with a subdomain on appspot.com | where UrlDomain matches regex @'\b[\w\-]+-dot-[\w\-\.]+\.appspot\.com\b' // Enrich results with sender and recipient data | join kind=inner EmailEvents on $left.NetworkMessageId==$right.NetworkMessageId // Phishing attempts from Appspot related campaigns typically contain the recipient's email address in the URI // Example 1: https://firstname.lastname@example.org // Example 2: https://email@example.com | where Url has RecipientEmailAddress // Some phishing campaigns pass recipient email as a Base64 encoded string in the URI or Url has base64_encode_tostring(RecipientEmailAddress) | project-away Timestamp1, NetworkMessageId1, ReportId1
Monitoring Multiple Distinct EDR Events per Host
To enhance the effectiveness of phishing attack detection, security teams can monitor multiple distinct endpoint detection and response (EDR) events per host. By correlating and analyzing EDR events from different hosts, organizations can identify patterns and trends associated with phishing attacks. This approach allows for a more comprehensive view of potential threats and enables organizations to respond more effectively to phishing attacks.
In conclusion, Microsoft Sentinel provides powerful tools and capabilities for detecting and mitigating phishing attacks. By leveraging KQL, integrating with Microsoft 365 Threat Protection, and implementing security automation with Logic Apps, organizations can proactively detect and respond to phishing threats. With Microsoft Sentinel, organizations can centralize and correlate security data, enabling a more comprehensive view of potential phishing attacks. By combining these tools and techniques, organizations can enhance their email security posture and protect against the ever-evolving threat of phishing attacks.
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