Clearing Logs in Cybersecurity: Why and How to Clear Logs

Logs are digital records that collect information on the events within a computer system or network. There are many different reasons to maintain logs, from helping with troubleshooting to monitoring user activity.

In the context of cybersecurity investigations, “clearing logs” refers to the action of intentionally deleting or removing log entries. While there are legitimate reasons to clear event logs, organizations need to ensure that they comply with the applicable laws and regulations and avoid the potential risks of doing so. This article will discuss everything you need to know about clearing logs: what it is, how to do it, the risks and consequences of doing so, and more.

Why Do Organizations Maintain Logs?

Organizations maintain logs (also known as “log retention”) for a variety of reasons, including:

• Troubleshooting and performance monitoring: Logs can record information about errors, technical problems, and performance issues within an IT environment. This data can be invaluable in helping IT administrators detect and resolve concerns.
•  Audits: External auditors may require organizations to keep logs as part of regulatory compliance requirements for laws such as HIPAA and GDPR. These logs prove user activities and system processes, confirming that the business has not violated laws or guidelines.
• Incident detection and response: Time is of the essence when a cyberattack occurs, and log monitoring can help IT security experts detect and respond to potential incidents more quickly. Logs record suspicious activities and anomalies that can be analyzed by SIEM (security information and event management) software.
• Digital forensics: Following a cyberattack or other crime, logs can play a crucial role in digital forensics, helping security analysts reconstruct the chain of events. Logs offer insights into how the attackers entered the network and what they did after the breach.
• Monitoring user activity: Logs record the actions of users within an IT environment, from the applications they use to the websites they visit. Businesses can use logs to keep track of user activity and ensure that they do not take unauthorized actions.

What Are the Ethical Considerations of Clearing Logs?

There are many good reasons to maintain logs; however, organizations may also wish to clear logs occasionally. The motives for clearing logs include:

• Performing routine maintenance (for example, to free up storage space).
• Deleting irrelevant data to help better monitor the IT environment.
• Preserving the privacy of sensitive personal data (e.g., in accordance with laws such as GDPR).

Organizations should clear logs in a controlled and responsible manner, accounting for their business requirements and legal obligations. Below are some ethical considerations when clearing logs:

• Transparency and accountability: Clearing logs can make it harder for organizations to remain transparent and accountable for their actions. Because logs record important IT events and user actions, clearing them without proper justification could be seen as an attempt to hide information.
• Hampering investigations: As discussed above, logs can be valuable evidence when looking into events such as a cyberattack. Clearing logs may impede these investigations, making it difficult or impossible to determine the root cause of a security breach.
• Legal and regulatory compliance: Maintaining logs may be necessary in the event of an audit or to comply with applicable laws and regulations. Organizations need to ensure that clearing logs does not prevent them from proving their compliance to external auditors.

How Can Logs Be Cleared?

The best way to clear logs is by using one of the various log management tools on the market. These solutions include Splunk, Datadog, SolarWinds Papertrail, Sumo Logic, and many more. Log management tools help users gather, store, and analyze the log data that they collect from the sources in their IT environment.

Logs can be cleared either manually or automatically:

• Manually clearing logs involves the actions of human employees, such as system administrators and other IT personnel. Users manually inspect logs to determine if they need to be retained or can be deleted.
• Automatically clearing logs involves the use of log management tools. Logs are automatically cleared when a specific event is triggered — for example, the log may be older than a specific date, or the system may have run out of storage space.

Whether clearing logs happens manually or automatically (or a mixture of both), organizations need to protect logs from unauthorized modification or deletion. The challenges and risks here include:

• Accidents: Users may accidentally delete entries that should have been retained when manually clearing logs. Automatic log management tools may also be configured incorrectly, causing them to unintentionally delete important information.
• Insider threats: Employees with hidden or malicious motivations may be insider threats, seeking to tamper with log data for their purposes. They might look to hide their actions or hinder the work of auditors or investigators.
• Cyberattacks: Savvy attackers often attempt to clear logs to cover their own tracks after breaching an organization’s defenses. This requires them to acquire additional permissions within the IT environment, a technique known as privilege escalation.

What Are the Consequences of Clearing Logs?

When organizations clear event logs, this can have both intended and unintended consequences. Clearing logs can result in outcomes such as:

• Incident response: If the logs of a security event are cleared, this can prevent organizations from effectively detecting and responding to intrusions.
• Forensic investigations: Cleared logs may contain crucial information that could be evidence in a digital forensics investigation.
• Legal proceedings: Organizations involved in legal proceedings may be subject to civil or criminal penalties if they destroy logs related to the case.
• Reputational damage: Clearing logs can damage an organization’s customer reputation, lowering its transparency and accountability.
• Regulatory compliance: Businesses may face repercussions from industry regulators and auditors who need to view log entries as part of their work.

How Can Organizations Ensure Log Integrity and Security?

In the face of these challenges and consequences, organizations need to preserve log integrity and security, only clearing logs when necessary. Below are some best practices when clearing logs:

• Retention policies: Logs should be retained for at least as long as the applicable laws and regulations require them to be stored.
• Access control: Organizations should restrict log access and deletion rights to employees with a solid business use case.
• Encryption: Encrypting logs in transit and at rest can help prevent malicious actors from viewing them and tampering with their contents.
• Secure storage: Logs should be stored in a secure place that requires users to authenticate their identity before viewing them.
• Backups: Organizations should keep log backups in a secondary location, especially logs needed for audits and regulatory compliance.

Learn About Clearing Logs in EC-Council’s C|EH Course

Clearing logs is a common practice in IT and cybersecurity that can be benign or malicious. While clearing logs can help reduce clutter and save on storage, attackers also do it to cover their tracks. IT experts, such as ethical hackers, should learn to recognize signs that logs have been cleared in their work investigating cyber incidents. EC-Council’s globally recognized Certified Ethical Hacker (C|EH) certification empowers learners with the latest tools, techniques, and resources of ethical hacking and pen testing. The program teaches students the fundamentals of ethical hacking across 20 domains, including the tools, techniques, and methodologies of clearing logs. Participants will have access to over 220 hands-on labs for real-world engagements.

Ready to launch your ethical hacking career? Learn more about EC-Council’s CEH certification today.

About the Author 

David Tidmarsh is a programmer and writer. He’s worked as a software developer at MIT, has a B.A. in history from Yale, and is currently a graduate student in computer science at UT Austin.