CVE-2023-25187: High severity nokia airscale vulnerability

An issue was discovered on NOKIA Airscale ASIKA Single RAN devices before 21B. Nokia Single RAN commissioning procedures do not change (factory-time installed) default SSH public/private key values that are specific to a network operator. As a result, the CSP internal BTS network SSH server (disabled by default) continues to apply the default SSH public/private key values. These keys don't give access to BTS, because service user authentication is username/password-based on top of SSH. Nokia factory installed default SSH keys are meant to be changed from operator-specific values during the BTS deployment commissioning phase. However, before the 21B release, BTS commissioning manuals did not provide instructions to change default SSH keys (to BTS operator-specific values). This leads to a possibility for malicious operations staff (inside a CSP network) to attempt MITM exploitation of BTS service user access, during the moments that SSH is enabled for Nokia service personnel to perform troubleshooting activities.