Defending business against cyberattack
Encryption of Data at Rest: The Cybersecurity Last Line of Defense
In the ever-evolving landscape of cybersecurity, where threats are becoming increasingly sophisticated and pervasive, traditional defenses alone are no longer sufficient to protect sensitive data. Despite the implementation of comprehensive security measures such as Zero Trust architectures and Defense in Depth strategies, organizations continue to experience significant security breaches. A critical vulnerability that remains is the exfiltration of data by cybercriminals. Unlike the ransomware attacks of the past that focused primarily on data encryption to demand ransom, modern adversaries now exfiltrate data, posing severe privacy and regulatory risks. In this context, encryption of data at rest emerges as the last and indispensable line of defense, rendering stolen data useless to attackers.
The Modern Threat Landscape
The shift from simply locking data to exfiltrating it marks a dangerous evolution in cyber threats. Cybercriminals today are not just interested in disrupting business operations but also in stealing valuable information. This stolen data can be used for identity theft, corporate espionage, or sold on the dark web, causing immense financial and reputational damage to organizations. In most instances, the exfiltrated data is used to compel organization to pay for ransom especially organizations operation in the industries (Health, Education) where privacy is a major requirement. Data exfiltration breaches are particularly concerning because they involve the unauthorized transfer of sensitive data from within the organization’s secure environment to an external location. For example, change healthcare cyber attack of 2024 which according to United Healthcare first quarter financial statement has cost the company about USD820m(https://www.cbsnews.com/news/unitedhealth-cyberattack-change-healthcare-hack-ransomware) happened in spite of the layers of defense that exist within the organization. etc.
The Inadequacy of Traditional Defenses
Despite advancements in cybersecurity practices, breaches still occur due to various factors, including sophisticated social engineering attacks, zero-day vulnerabilities, supply chain attack, poor implementation of sophisticated defense technology and insider threats. Zero Trust, which operates on the principle of “never trust, always verify,” and Defense in Depth, which layers multiple security controls, are robust frameworks. However, even these can be circumvented by determined attackers, leaving data exposed and organizations vulnerable to significant fallout.
Understanding Different States of Data:
Data can exist in three distinct states:
- Data in Transit: This is data actively moving from one location to another, such as over a network.
- Data at Rest: This is data stored on a physical medium, like a database server, hard drive or cloud storage, and not actively being used.
- Data in Use: This is data currently being processed or accessed by a system.
For example, when you send an email, the message is considered data in transit. Once it reaches the recipient’s inbox, it becomes data at rest. If the recipient opens and reads the email, it turns into data in use. Eventually, all data typically returns to a resting state for storage and future access.
While there are various encryption schemes for data in transit, less has been done to encrypt data at rest. Consequently, once security defenses are breached by malicious actors, the data becomes vulnerable. Encrypting data at rest complements the cybersecurity defense system and ensures that even if bad actors manage to defeat the security mechanisms, their efforts have little effect.
The Role of Encryption in Data Protection
Encryption of data at rest involves converting sensitive data stored on physical media into an unreadable format using cryptographic algorithms. This process ensures that, even if cybercriminals manage to breach the perimeter defenses and access the storage devices, the data remains unintelligible without the decryption key. Here’s why encryption of data at rest is crucial in the current cybersecurity climate:
- Nullifying Data Exfiltration Risks
- When data is encrypted at rest, any exfiltrated data becomes useless to the attackers. Without the decryption keys, the data cannot be read or exploited, thereby mitigating the impact of the breach. This is particularly vital in preventing the misuse of sensitive information such as personal identifiable information (PII), financial records, and intellectual property.
- Compliance with Privacy Regulations
- Regulatory frameworks such as GDPR, HIPAA, and CCPA mandate strict measures for protecting sensitive data. Encryption helps organizations comply with these regulations by ensuring that stolen data remains protected, thereby avoiding hefty fines and legal consequences associated with data breaches.
- Maintaining Customer Trust
- Data breaches can severely damage an organization’s reputation and erode customer trust. By implementing encryption of data at rest, companies can reassure their clients and stakeholders that they are taking all necessary steps to protect their data, even in the event of a security breach.
Implementing Effective Encryption Strategies
To maximize the effectiveness of encryption as the last line of defense, organizations must adopt a comprehensive approach:
- Identify and Classify Sensitive Data
- Conduct thorough assessments to identify which data needs to be encrypted. This typically includes PII, financial information, intellectual property, and any other sensitive business data.
- Select Robust Encryption Algorithms
- Choose industry-standard encryption algorithms such as Advanced Encryption Standard (AES) with 256-bit keys, which provide a high level of security and are widely recognized for their effectiveness. There are some encryption methods that have been deprecated and should not be used.
Below are some of the deprecated encryption algorithms that must be avoided:
DES (Data Encryption Standard):
- Reason for Deprecation: DES uses a 56-bit key, which is too short to provide adequate security against brute-force attacks. Modern computing power can crack DES encryption relatively quickly.
3DES (Triple DES):
- Reason for Deprecation: While 3DES was designed to improve the security of DES by applying the DES algorithm three times with different keys, it still has vulnerabilities and is relatively slow compared to newer algorithms. It also has a shorter effective key length and is susceptible to certain attacks.
MD5 (Message-Digest Algorithm 5):
- Reason for Deprecation: MD5 is a hash function rather than an encryption method, but it is included here because it is often used in contexts requiring secure hashing. MD5 is vulnerable to collision attacks, where two different inputs produce the same hash output, making it unsuitable for cryptographic security.
SHA-1 (Secure Hash Algorithm 1):
- Reason for Deprecation: Similar to MD5, SHA-1 is a hashing algorithm and has been found vulnerable to collision attacks. The computational feasibility of these attacks has rendered SHA-1 insecure for most cryptographic purposes.
RC4 (Rivest Cipher 4):
- Reason for Deprecation: RC4 has several vulnerabilities, including biases in its output that can be exploited in certain attacks. It is considered weak and is no longer recommended for use in secure communications.
- Employ Strong Key Management Practices
- Implement centralized key management systems to securely generate, store, and manage encryption keys. Ensure that access to encryption keys is tightly controlled and monitored to prevent unauthorized access.
- Encrypt All Storage Solutions
- Apply encryption across all storage mediums, including databases, file systems, and backup storage. For cloud environments, use encryption services offered by the cloud provider or deploy your own encryption solutions.
- Regularly Update and Audit Systems
- Keep encryption software, operating systems, and hardware security modules updated with the latest patches. Conduct regular audits to ensure compliance with security policies and identify potential vulnerabilities.
Overcoming Challenges
While encryption is a powerful tool, it is not without challenges. Organizations must balance the need for security with performance, as encryption can introduce processing overhead. Effective key management is also critical to avoid the risk of key loss, which could render data permanently inaccessible. However, with careful planning and implementation, these challenges can be managed effectively.
Conclusion
In the face of evolving cyber threats, encryption of data at rest stands as the last and most resilient defense against data breaches. By transforming sensitive data into an unreadable format, encryption ensures that even if cybercriminals penetrate other security layers and exfiltrate data, it remains unusable without the decryption keys. This not only protects organizations from severe privacy and regulatory repercussions but also helps maintain customer trust in a time where data security is paramount. In the cybersecurity defense lineup, encryption of data at rest is not just an option—it is an essential safeguard in safeguarding the digital fortress.
About the Author
Abimbola Ogunjinmi (MCMC, MNSE, MIEEE, mISC2, mISACA), is a distinguished leader in secure Technology infrastructure deployment. With a scholarly bias for cybersecurity and over two decades of hands-on experience in Information Technology and Telecommunication Infrastructure deployment, he has established himself as a formidable figure in the field. Beginning his career as an engineer, Abimbola has ascended to prominence through his expertise in technology infrastructure deployment. He holds a myriad of industry certifications from ISC2, PMI, Scrum, Cisco, Nokia, Alcatel-Lucent and EXIN. He earned certification such as project management professional (PMP) and Scrum product owner, Scrum Master, CCNP, CCDP, NRS, and ITIL certifications. Abimbola is a prolific contributor to both emerging and legacy technologies, including but not limited to 5G, cyber defense technologies, AI, wireless transmission, satellite communication, and Optical network systems.
Abimbola can be reached online at https://www.linkedin.com/in/abimbolaogunjinmi/