Summary
The issue at hand is a TLS certificate verification failure on a Raspberry Pi running Debian 9, where the system is unable to verify the server’s certificate due to a missing root CA certificate. Despite extracting and installing the intermediate certificate, the verification process still fails.
Root Cause
The root cause of this issue is that the root CA certificate is not present in the system’s trusted CA bundle. The reasons for this include:
- The server does not send the root certificate
- The root certificate must already exist in the client’s trusted CA bundle
- Older Debian versions may have outdated CA certificates
Why This Happens in Real Systems
This issue occurs in real systems due to:
- Outdated CA certificates in older Debian versions
- Incomplete certificate chains, where the root CA certificate is not sent by the server
- Insufficient trust, where the intermediate certificate is installed but the root CA certificate is not trusted
Real-World Impact
The real-world impact of this issue includes:
- Failed TLS connections, resulting in errors and failed communication
- Security risks, as unverified certificates can lead to man-in-the-middle attacks
- System downtime, as administrators struggle to resolve the issue
Example or Code (if necessary and relevant)
openssl s_client -connect :443 -servername This command can be used to test the TLS connection and verify the certificate chain.
How Senior Engineers Fix It
Senior engineers fix this issue by:
- Installing the root CA certificate in the system’s trusted CA bundle
- Updating the CA certificates to ensure they are current and trusted
- Verifying the certificate chain to ensure it is complete and valid
Why Juniors Miss It
Junior engineers may miss this issue due to:
- Lack of understanding of the TLS certificate chain and trust model
- Insufficient experience with certificate verification and trust issues
- Failure to test the certificate chain and verify its validity