Logs

Logs are a critical component of a Security Operations Centre (SOC), providing the foundational data required for detecting, investigating, and responding to cyber security incidents. They serve as a detailed record of system and network activities, enabling SOC analysts to monitor for suspicious behaviour, identify potential threats, and conduct forensic analysis in the event of a breach.

Logs

1. Threat Detection:

Logs capture every action performed on systems and networks, such as login attempts, file access, changes to configurations, and network traffic. By analysing logs in real-time, SOC teams can detect unusual patterns or anomalies that may indicate an attack. Security tools like SIEM (Security Information and Event Management) aggregate log data from various sources, allowing analysts to correlate different events and generate alerts when predefined rules are triggered.

For instance, a failed login attempt from an unfamiliar location followed by a successful login might raise a red flag. Without detailed logs, detecting such an incident would be much more difficult, as there would be no historical record to examine.

2. Incident Investigation and Forensics:

When a security incident occurs, logs are essential for understanding the nature, scope, and impact of the attack. They provide the timeline of events, helping SOC teams to trace the attacker’s actions and determine how the compromise happened. This includes identifying the initial point of entry, which systems were affected, and whether any data was exfiltrated. Logs also help analysts understand the attacker’s tactics, techniques, and procedures (TTPs), which can be used to strengthen defences against future attacks.

Logs also support compliance with regulatory requirements such as GDPR, which mandates organisations to track and report security incidents. Detailed log data provides evidence that an incident has been properly managed and can be used in legal or regulatory investigations.

3. Monitoring and Auditing:

Comprehensive logging allows SOC teams to continuously monitor systems and users for suspicious behaviour. Logs also serve as an audit trail for system activities, making it easier to verify whether proper security practices are being followed. Regular audits of log data can help identify misconfigurations, policy violations, or unauthorised access, giving SOC teams the opportunity to address these issues before they lead to a security breach.

4. Improving Security Posture:

Logs provide valuable insights into the overall security health of an organisation. By reviewing logs over time, SOC teams can identify recurring vulnerabilities or threats and adjust security measures accordingly. This helps in fine-tuning detection rules, improving incident response strategies, and enhancing the overall efficiency of the SOC.

Logs are indispensable for detecting threats, conducting incident investigations, maintaining compliance, and improving the organisation’s security posture. Without effective logging practices, SOCs would lack the visibility necessary to protect against cyber threats.

Examples of Logs

Authentication Logs: These capture login attempts, both successful and failed, along with the associated IP address, username, and timestamp. For example, a record showing a user logging in from an unfamiliar location could indicate a compromised account.

Firewall Logs: These track network traffic, showing which IP addresses are allowed or denied access to the network. They can highlight suspicious traffic, such as attempts to access blocked ports or unauthorised IPs.

System Event Logs: These record key system events like software installation, service failures, and configuration changes. For example, an unexpected change in system settings could indicate malicious activity.

Application Logs: These capture activity within specific software applications, such as file uploads, database queries, or API requests. An application log might show unusual data access patterns, signalling an insider threat or a data breach.

Network Logs: These monitor network activity, capturing information like packet transfers, bandwidth usage, and network errors. They help in detecting anomalies such as data exfiltration or large amounts of traffic to unfamiliar domains.

Intrusion Detection/Prevention System (IDS/IPS) Logs: These record suspicious activities flagged by security systems, such as attempted exploits or malicious payloads.

Sensitive Personal Data: Logs should not capture personal identifiable information (PII) unnecessarily, such as national insurance numbers, personal addresses, or credit card details. This can lead to privacy violations or non-compliance with regulations like GDPR.

Passwords: Logs should never include passwords, even in encrypted or hashed formats. Storing passwords in logs increases the risk of them being exposed if the logs are compromised.

Sensitive Business Information: Confidential business information, such as proprietary data, intellectual property, or internal strategies, should not be logged unless absolutely necessary. This minimises the risk of sensitive data leakage in the event of a breach.

Unnecessary User Input: Logs should avoid capturing free-text inputs or large amounts of unfiltered user data, as these can inadvertently expose sensitive information.

Redundant or Excessive Data: Logging excessive amounts of data, such as every single keystroke or mouse click, can clutter the logs and make it harder to identify important security events. Logs should be kept concise and relevant.

By ensuring that logs contain relevant security data without sensitive or excessive information, organisations can maintain a strong security posture while respecting privacy and compliance requirements.

What Should Not Be Included in Logs:

A Security Operations Centre (SOC)