Cloud Logs: The Unsung Heroes of Detection and Response

Cyberattackers are exploring stealthier and more sophisticated methods to infiltrate cloud environments. From exploiting misconfigurations to leveraging stolen credentials, adversaries are skilled at evading detection. Cloud logs are invaluable in helping organizations identify potential threats before they can cause damage.

Silent yet powerful, cloud logs are the unsung heroes in the ongoing battle against cyberattacks, providing the crucial data needed to detect, investigate and mitigate risks in real time.

What Are Cloud Logs?

Cloud logs capture every action that occurs within a cloud environment, ranging from user activities to system-level events. They are captured in distinct layers tailored to specific service types. There are four main categories that these logs typically fall into:

• Management or control logs: Provides the broadest coverage and tracks many administrative activities in the cloud, such as resource and account creation and modification. Examples include AWS CloudTrail and Google Workspace audit logs.
• Data logs: Tracks data downloads, modifications, exporting, etc. 
• Network traffic logs: Captures connectivity and routing between cloud instances and external sources. Examples include AWS VPC flow logs and Azure NSG flow logs.
• Service-specific logs: Monitors access to specific cloud services — for example, AWS S3 access logs.

Why Cloud Logs Matter More Than Ever

As organizations move critical workloads to the cloud, they face a new range of security challenges. Common adversary tactics include:

• Credential theft and identity misuse
• Privilege escalation within cloud services
• Lateral movement between cloud instances

Unlike traditional on-premises environments, cloud infrastructure resources are dynamic and ephemeral, constantly changing and distributed across various services and regions. Attackers can exploit these characteristics to stay hidden and avoid detection for long periods. Cloud logs record a comprehensive history of activity and events across the entire cloud ecosystem, including the activities and actions of every user or entity.

When combined with real-time data, cloud logs help teams identify where breaches could occur and which assets are most exposed. They help incident detection and response teams determine the best course of action for addressing findings and anomalies. Finally, cloud logs supply much of the forensic information needed during investigations and subsequent followup.  

These logs provide deep visibility into the resource and service layers of cloud environments, enabling security teams to monitor for suspicious behavior, identify vulnerabilities and detect unauthorized actions.

In the event of a breach, cloud logs are essential for incident response. They serve as the digital evidence needed to understand how an attack unfolded, which systems were compromised and what actions were taken by the attacker. By reviewing cloud logs, security teams can determine the point of initial access, trace lateral movements across environments and domains, and assess the extent of the damage. This information is critical for informing both immediate remediation efforts and long-term improvements to the organization's security posture. 

Cloud Log Regulations

Logs, including cloud logs, are so critical to security and incident investigations that there are multiple regulatory requirements on the specific records organizations must keep and how long they must keep them. Some regulations, like HIPAA and SOX, are industry-specific. Others, like CCPA in California and GDPR in Europe, are regional. In addition, there are multiple frameworks, like NIST and CIS, that support best practices for log retention. Cloud logs are generally more complex because they involve data from multiple sources and can be distributed across regions, zones and cloud service providers. 

How Cloud Logs Detect Sophisticated Attacks

Sophisticated cyberattacks often follow a multi-step process, from initial access to lateral movement and data exfiltration. Here’s what different types of cloud logs can reveal in each phase.

#1: Detecting Privilege Escalation

Attackers frequently gain access to low-privileged accounts and escalate privileges to achieve greater control over cloud resources. Management logs capture all attempts to modify roles or assign elevated privileges, making it possible to detect unauthorized changes early on. For example, if an attacker gains access to a compromised account and tries to assign themselves administrative privileges, these logs will record this action, allowing security teams to take immediate corrective action.

#2: Monitoring Anomalous Network Traffic

Attackers may attempt to move laterally across cloud environments, searching for vulnerabilities or exploiting cloud services. Network logs, such as VPC flow logs, capture detailed information about incoming and outgoing network traffic. These logs can reveal suspicious connections between cloud instances, unexpected data transfers or traffic anomalies that could indicate an ongoing attack. For example, if data is being exfiltrated to an external IP address, flow logs will document the traffic pattern, enabling timely detection.

#3: Identifying (and Fixing) Misconfigurations

Cloud misconfigurations can lead to security breaches and data leaks, making service-specific logs critical for monitoring configuration changes and identifying potential vulnerabilities. If an S3 bucket is accidentally made public or a firewall rule is misconfigured to allow unrestricted access, audit logs will capture these changes. 

Taking this one step further and using logs in conjunction with cloud security posture management (CSPM) will help teams address misconfigurations and prevent exploitation. The findings from cloud logs can serve as triggers that, when combined with CSPM, help organizations with near real-time configuration monitoring, dynamic policy updates, automated remediation and compliance validation. 

#4: Correlating Events from Multiple Sources and Across Services

The true power of cloud logs is unlocked when different logs are correlated to reveal a comprehensive picture of an attack. For example, a suspicious login attempt captured in management or control logs can be correlated with abnormal network traffic from VPC flow logs, leading to a deeper understanding of the potential threat. Different service logs can also identify events that might otherwise go unnoticed. 

For example, an identity provider service log from Okta can show that a user logged in successfully, but from a new geolocation. AWS IAM logs can indicate user actions like listing S3 buckets, followed by data download actions. Finally, AWS S3 access logs will reveal whether data was accessed, downloaded or shared outside approved channels. Linking suspicious login activity in Okta with unusual data access patterns helps teams detect and investigate potential data exfiltration attempts.

How to Get the Most from Your Cloud Logs

Modern cloud environments generate massive amounts of log data, making analysis impractical, insights hard to find, events difficult to prioritize, and remediation slow to orchestrate. Here are some ways to maximize the effectiveness of your cloud logs. 

• Automate alerts to trigger immediate notifications when cloud logs reveal a potential breach, such as a sudden spike in network traffic or an unauthorized privilege escalation.
• Leverage machine learning and AI to supercharge cloud log analysis, as organizations are processing a tremendous volume of data daily. What's particularly challenging is that activity patterns can vary significantly between environments. For example, an alert-worthy event in one organization’s infrastructure might be normal in another's.
• Automate responses, such as revoking compromised credentials or blocking malicious IP addresses, to be triggered directly from log analysis, enabling faster containment of attacks.
• Combine logs with sensor-based workload protection to add a real-time layer that identifies threats as they happen. Together, they give security teams full visibility into both past (logs) and present (sensor) activities, enabling faster detection and response.
• Seek out managed services to augment your team. A team of dedicated professionals can help analyze cloud logs, along with many other security data points, to help organizations overcome the cybersecurity skills shortage.

Cloud Logs Power Cloud Detection and Response 

Cloud logs are critical for fueling modern detection and response capabilities. They provide the deep visibility needed to detect threats that might go undetected, respond to active threats quickly and mitigate potential damage. 

By continuously feeding cloud logs — along with signals from the CrowdStrike Falcon® agent and CrowdStrike threat intelligence — through the unified Falcon platform, CrowdStrike Falcon® Cloud Security can correlate seemingly unrelated events across distributed environments and domains so organizations can protect themselves from even the most advanced adversaries.

Cloud logs may not be the most exciting or innovative topic, but their role in modern cybersecurity remains vital. 

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Additional Resources

• Read how a customer improved its security with Falcon: Aflac Drives Consolidation with the Falcon Platform, Eliminating 15 Point Security Tools in Three Years
• Learn about Falcon Cloud Security’s recognition as an industry leader: CrowdStrike named a Leader: 2024 Forrester Wave™ for Cloud Workload Security