Detecting Phishing and Insider Threats Using Wazuh

Phishing and insider threats continue to pose significant, often overlapping risks in modern threat landscapes. Compromised credentials obtained through phishing campaigns or social engineering attacks can grant adversaries legitimate access, effectively converting external threats into insider risks. This convergence complicates detection, as malicious activity may closely mimic authorized user behavior.

To address this challenge, security teams require a platform that can correlate events from multiple sources, including endpoints, users, and network activity. Security teams, therefore, need a Security Information and Event Management (SIEM) platform that can collect and correlate activity across endpoints, users, and network sources. A SIEM platform enables the aggregation and correlation of data from multiple sources, helping analysts uncover suspicious patterns that would otherwise go unnoticed.

Phishing attacks

Phishing attacks remain among the most effective techniques used by attackers to gain initial access to an organization. Rather than exploiting software vulnerabilities, it targets human behavior, leveraging trust, urgency, and deception to manipulate users into revealing sensitive information or executing malicious actions.

A typical phishing attack begins with a carefully crafted email or message impersonating a trusted entity. It may impersonate a trusted brand, a colleague, or even an internal system. Once a user interacts with a link or downloads an attachment, the attacker can harvest credentials, deploy malware, or redirect the victim to a fake login portal. This often provides an initial foothold for lateral movement across systems and privilege escalation.

Phishing is particularly dangerous because it often bypasses traditional perimeter defenses. Since the user initiates the action, the activity can appear normal and legitimate, making early detection critical.

Common characteristics of phishing attacks include:

• Spoofed or lookalike domains that mimic legitimate services
• Urgent or emotionally manipulative messaging designed to prompt immediate action
• Malicious links leading to credential harvesting pages
• Attachments containing embedded malware or script-based payloads

Although phishing may appear isolated, it typically leaves behind detectable traces, such as unusual login attempts, access to suspicious domains, or execution of unfamiliar files. Correlating these indicators is key to identifying the attack before it escalates.

Insider threats

Insider threats represent a different class of risk, as they originate from within the organization. These threats can come from employees, contractors, or partners who already have legitimate access to systems and data. Unlike external attackers, insiders do not need to bypass authentication controls, which makes their activities harder to distinguish from normal operations.

Not all insider threats are malicious. In many cases, they stem from negligence or lack of awareness, such as mishandling sensitive data or falling victim to phishing attacks. However, they can also involve intentional actions, such as data exfiltration, system sabotage, or privilege abuse.

What makes insider threats particularly challenging is their subtlety. Activities such as accessing files, modifying data, or running administrative commands may all fall within the scope of a user's role. The key to detecting insider threats lies in identifying deviations from established patterns rather than isolated events.

Typical indicators of insider threats include:

• Access to sensitive data outside of normal job responsibilities
• Unusual login patterns, such as odd hours or unfamiliar locations
• Sudden escalation of privileges or use of administrative tools
• Attempts to modify or delete logs and critical system files

In many cases, insider threats result from compromised accounts, often following a successful phishing attack. This connection highlights the importance of a unified detection strategy that can correlate user behavior, system activity, and external threat intelligence to uncover risks that would otherwise remain hidden.

How to mitigate phishing attacks and insider threats.

Organizations can leverage the Wazuh unified platform to correlate user behavior, system activity, and external threat indicators by combining its several core security capabilities. These include:

• Log data analysis: Aggregates and correlates logs from email servers, web gateways, and endpoints to identify suspicious patterns such as unusual login attempts or access to malicious domains.
• File Integrity Monitoring (FIM): Detects unauthorized access, modifications, or deletions of critical files, which helps spot data exfiltration or attempts to cover tracks.
• Threat intelligence integration: Enriches alerts with contextual data about file hashes, IP addresses, and domains to quickly validate known phishing indicators in near real time.
• Command monitoring: Provides visibility into endpoint activity, enabling detection of suspicious executions or misuse of administrative tools.

Use cases

Detecting phishing attacks with Wazuh

Wazuh enables organizations to detect phishing activity by aggregating and analyzing logs from multiple sources, including email servers, web gateways, and endpoints. By correlating these data points, it becomes possible to identify suspicious patterns such as unusual login attempts, access to known malicious domains, or the execution of files linked to phishing campaigns.

In the detecting phishing attacks with Wazuh and Shuffle use case, Wazuh provides real-time threat security monitoring to identify suspicious email activity. This integration with Shuffle also provides alert enrichment and automated responses to suspicious emails. This integration allows security teams to quickly determine whether a link or attachment is malicious, which would help with further investigations.

Identifying insider threats with Wazuh

Detecting insider threats requires visibility into user behavior and system activity. Wazuh achieves this by continuously monitoring authentication events, privilege changes, and access to sensitive resources, and file modifications.

Monitoring remote OpenVPN connections with Wazuh illustrates how unusual user activity, such as a login from an unknown or unauthorized location, can be detected. This is particularly useful in scenarios where an authorized system has been compromised by a malicious actor. The malicious actor may log in from an unauthorized location to exfiltrate sensitive data, and Wazuh can flag such activity for your security team to investigate.

Security misconfigurations are another example of insider threats that can originate from improper user configuration on endpoints. In this blog post, Wazuh automates remediation for security misconfigurations using its Security Configuration Assessment (SCA) and Command modules. The image below shows the CIS benchmark score for a monitored endpoint before an automated security misconfiguration remediation was applied by Wazuh

The image below shows that the total number of passed items has increased from 100 to 135 after the remediation has been completed.

Conclusion

Phishing and insider threats are no longer isolated challenges; they are interconnected risks that require a unified detection strategy. Wazuh provides the visibility and correlation needed to detect both early-stage phishing activity and the resulting insider-like behavior that often follows.