CVE-2017-17704 : Exploit Details and Defense Strategies

Software House iStar Ultra devices up to version 6.5.2.20569, when used with the IP-ACM Ethernet Door Module, are vulnerable to replay attacks due to a flaw in the encryption mechanism.

Understanding CVE-2017-17704

Software House iStar Ultra devices are affected by a cryptographic vulnerability that allows unauthorized access to doors.

What is CVE-2017-17704?

The issue lies in the communication between the IP-ACM and iStar Ultra devices, where messages are encrypted in CBC mode with a fixed IV, making them susceptible to replay attacks and message forgery.

The Impact of CVE-2017-17704

This vulnerability could lead to unauthorized individuals gaining access to secure areas by exploiting the flawed encryption process.

Technical Details of CVE-2017-17704

Software House iStar Ultra devices are affected by a cryptographic weakness that compromises the security of door access control systems.

Vulnerability Description

The flaw allows attackers to replay entire messages and forge new ones due to the predictable IV and lack of message authentication beyond the fixed AES key.

Affected Systems and Versions

Software House iStar Ultra devices up to version 6.5.2.20569
Specifically when used with the IP-ACM Ethernet Door Module

Exploitation Mechanism

Messages encrypted in CBC mode with a fixed IV
Lack of message authentication beyond the fixed AES key

Mitigation and Prevention

Steps to address and prevent the exploitation of CVE-2017-17704

Immediate Steps to Take

Update affected devices to the latest firmware version
Implement additional access control measures

Long-Term Security Practices

Regularly review and update encryption protocols
Conduct security audits and penetration testing

Patching and Updates

Apply patches and security updates provided by the vendor to address the cryptographic vulnerability