CVE-2024-25077

Comprehensive Technical Analysis of CVE-2024-25077

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2024-25077 CVSS Score: 9.8

The vulnerability in Renesas SmartBond DA14691, DA14695, DA14697, and DA14699 devices involves the storage of the Nonce used for on-the-fly decryption of flash images in an unsigned header. This allows an attacker to modify the Nonce without invalidating the signature used for secure boot image verification. The encryption engine uses AES in CTR mode without authentication, which can lead to the execution of arbitrary code if the Nonce is altered.

Severity Evaluation:

• CVSS Score: 9.8 (Critical)
• Impact: High
• Exploitability: High

The high CVSS score indicates a critical vulnerability that can be easily exploited with severe consequences, including arbitrary code execution.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Local Access: An attacker with physical access to the device can modify the Nonce in the unsigned header.
2. Network Access: If the device is connected to a network and the firmware update process is not properly secured, an attacker could remotely modify the Nonce.
3. Supply Chain Attack: An attacker could intercept and modify the firmware during the supply chain process before it reaches the end-user.

Exploitation Methods:

1. Nonce Modification: The attacker modifies the Nonce in the unsigned header, which does not invalidate the signature.
2. AES CTR Mode Exploitation: The attacker leverages the lack of authentication in AES CTR mode to manipulate the decryption process, leading to arbitrary code execution.

3. Affected Systems and Software Versions

Affected Devices:

• Renesas SmartBond DA14691
• Renesas SmartBond DA14695
• Renesas SmartBond DA14697
• Renesas SmartBond DA14699

Software Versions:

• All firmware versions that use the affected secure boot mechanism with AES CTR mode for on-the-fly decryption.

4. Recommended Mitigation Strategies

1. Firmware Update: Apply the latest firmware updates provided by Renesas that address this vulnerability.
2. Secure Boot Enhancements: Implement additional security measures such as signed headers and authentication mechanisms for the encryption process.
3. Access Control: Restrict physical and network access to the devices to prevent unauthorized modifications.
4. Supply Chain Security: Ensure the integrity of the firmware throughout the supply chain process.
5. Monitoring and Logging: Implement monitoring and logging mechanisms to detect any unauthorized access or modifications to the firmware.

5. Impact on Cybersecurity Landscape

This vulnerability highlights the importance of secure boot mechanisms and the need for robust encryption and authentication processes. The potential for arbitrary code execution underscores the critical nature of securing firmware updates and the supply chain. Organizations using affected devices must prioritize patching and implementing additional security measures to mitigate the risk.

6. Technical Details for Security Professionals

Technical Overview:

• Nonce Storage: The Nonce used for on-the-fly decryption is stored in an unsigned header, allowing modification without invalidating the signature.
• Encryption Mode: AES in CTR mode is used for decryption without authentication, making it vulnerable to manipulation.
• Secure Boot Mechanism: The secure boot process relies on the integrity of the Nonce and the encryption process, both of which are compromised in this vulnerability.

Mitigation Steps:

1. Signed Headers: Ensure that all headers, including the Nonce, are signed and verified during the secure boot process.
2. Authentication: Implement authentication mechanisms for the encryption process to prevent unauthorized modifications.
3. Firmware Integrity: Use cryptographic hashes and digital signatures to verify the integrity of the firmware during updates.
4. Access Control: Implement strict access control policies to prevent unauthorized access to the device and its firmware.

References:

• ATREDIS Advisory

By addressing this vulnerability, organizations can enhance the security of their IoT devices and protect against potential attacks that could lead to arbitrary code execution.