Data Leakage Prevention(DLP) with ISO 27001
- Kamalika Majumder | DevOps & ISO 27001 Consultant
- Aug 11, 2025
- 4 min read
How ISO 27001 Addresses Data Leakage Prevention(DLP)
In one of my client projects where we had to use Alibaba Cloud, they took our ids, bank statements and whatnot just to verify and activate our cloud account. And then after all that, we would often see random public IPs being added to our VPC network by someone, which traced their origin back to Mainland China. One being asked their explanation was, "these are IPs of the management server which monitor and scan your systems as part of your managed services".
This was a constant point of contention for most Cloud services launched in Indonesia since 2020. OJK, the Indonesian Financial Services Authority, requires all Banking & Financial Services applications to host their PII data within Indonesia. To achieve this all Cloud providers must have their datacenters located within the country to safeguard data confidentiality and integrity.
Data leakage poses a significant risk to organisations, potentially leading to financial loss, reputational damage, and regulatory penalties. ISO 27001, the globally recognised standard for information security management, provides a structured framework to prevent data leakage through a combination of policies, technical controls, and continuous monitoring. This article explores how ISO 27001 helps organisations address data leakage prevention effectively.
Understanding Data Leakage
Data leakage occurs when sensitive or confidential information is accidentally or maliciously exposed to unauthorised individuals. This can happen through various channels, such as:
Email and Messaging Applications – Sending sensitive data to the wrong recipient or unencrypted transmissions.
Removable Storage Devices – Unauthorized copying of data onto USB drives or external hard disks.
Cloud and File Sharing Services – Insecure sharing of files via public cloud platforms.
Printing and Physical Documents – Mishandling printed documents that contain confidential information.
Insider Threats – Employees or third-party contractors intentionally or unintentionally exposing data.
ISO 27001 Framework for Data Leakage Prevention(DLP)
According to Annex A control A.8.12, ISO 27001 Data Leakage Prevention(DLP) shall be applied to systems, networks and any other devices that process, store or transmit sensitive information.
ISO 27001 provides a systematic approach to managing sensitive company information, ensuring that it remains secure. The standard follows a risk-based methodology, implementing controls that specifically address data leakage risks. Here are some key areas where ISO 27001 plays a crucial role:
1. Establishing a Strong Information Security Policy
One of the fundamental requirements of ISO 27001 is the development and enforcement of an information security policy. This policy outlines how data should be handled, stored, and transmitted, ensuring employees and stakeholders adhere to best practices to prevent leakage.
2. Access Control and Least Privilege Principle
ISO 27001 mandates robust access control mechanisms to restrict unauthorised access to sensitive data. Organisations implement:
Role-Based Access Control (RBAC) – Ensuring employees have access only to the data they need.
Multi-Factor Authentication (MFA) – Strengthening identity verification.
Periodic Access Reviews – Auditing and revoking unnecessary access rights.
3. Data Classification and Handling
The standard requires organisations to classify data based on sensitivity levels, such as public, internal, confidential, and restricted. Once classified, ISO 27001 mandates handling guidelines, including encryption, secure storage, and controlled distribution of sensitive data.
4. Encryption and Secure Transmission
To mitigate risks associated with data interception, ISO 27001 enforces encryption protocols for data at rest and in transit. This includes:
End-to-End Encryption (E2EE) – Protecting data during transmission.
Disk and File Encryption – Securing stored sensitive information.
Secure Communication Channels – Utilizing VPNs, TLS, and SSL for data exchange.
5. Security Awareness and Employee Training
Human error is a common cause of data leakage. ISO 27001 emphasizes the need for regular security training programs, ensuring employees understand:
Risks associated with mishandling data.
Proper use of communication and storage tools.
Reporting procedures for suspected data leaks.
6. Monitoring and Logging of Activities
ISO 27001 requires continuous monitoring of network activities and logging user actions to detect and prevent unauthorized access or suspicious behavior. Security Information and Event Management (SIEM) systems play a crucial role in:
Identifying potential data breaches.
Generating alerts for unusual activities.
Conducting forensic investigations post-incident.
7. Secure Third-Party and Supply Chain Management
Third-party vendors and contractors often have access to an organization's sensitive data. ISO 27001 mandates rigorous supplier assessments and contractual agreements, ensuring they comply with data protection requirements. Security audits and compliance checks help mitigate risks arising from external parties.
8. Incident Response and Data Breach Management
Despite best efforts, data leakage incidents can still occur. ISO 27001 requires organizations to establish an incident response plan that includes:
Immediate containment and mitigation of breaches.
Incident reporting mechanisms.
Root cause analysis and corrective actions to prevent recurrence.
9. Regular Security Audits and Continuous Improvement
ISO 27001 follows a continuous improvement model, requiring organizations to conduct:
Periodic Security Audits – Evaluating the effectiveness of existing controls.
Vulnerability Assessments and Penetration Testing – Identifying weaknesses before they can be exploited.
Policy and Procedure Updates – Adapting security measures to evolving threats.
Conclusion:
Data leakage prevention is a critical aspect of information security, and ISO 27001:2022 provides a comprehensive framework to address this challenge.
By implementing access controls, encryption, monitoring, and employee awareness programs, organisations can significantly reduce the risk of data leaks.
Adopting ISO 27001 not only enhances data security but also builds trust with customers, partners, and regulatory bodies, ensuring compliance with international security standards.
Need to get ISO 27001 or SOC2 Compliant, but not sure where to start!
Thanks & Regards
Kamalika Majumder
