Symptom

Sftunnel connection failed to the device after the FMC upgrade. FMC side verification of certificate is failing with "err 68:CA signature digest algorithm too weak".

Conditions

Workaround

On the FMC: 1. Revoke existing certificate for this device on FMC: a.Get the device UUID. b.Select cert_serial_number,service from ssl_peer \G; c.select service from ssl_peer where cert_serial_number=; is cert_serial_number which is matching with the device UUID in step 2 then Verify the device UUID 2. The run the ?sfca_revoke /etc/sf/ca_root ? with the number found from previous step. 1. Find the entry from ?/etc/sf/ca_root/index.txt? for the device UUID, all the records should start with ?R? (revoked). It has a hexadecimal value in 3rd column, matching the cert_serial_number found earlier. Specifically that entry should have value as ?R? in the 1st column. a. cat /etc/sf/ca_root/index.txt|grep 3. Clean up ssl_peer table for this device UUID a.delete from ssl_peer where cert_serial_number = ; 3. Issue new certificate on FMC for the device, run the below command from /var/sf/peers/ directory : a. perl -e 'use FlyLoader;use Data::Dumper; print SF::PeerManager::RegUtils::generateCert("/var/sf/peers//","sftunnel","localhost","");' 5. Find the entry from ?/etc/sf/ca_root/index.txt? for the device UUID, all the records with start with ?V? (valid). It has a hexadecimal value in 3rd column, matching the cert_serial_number, hexadecimal value. This is to verify that a certificate has been issued. 6. sftunnel-key.pem and sftunnel-cert.pem files are created in the /var/sf/peers/ directory on FMC. 7. Copy the issued certificate to the FTD and place it under /var/sf/peers// on the FTD. 7.1 Move away/rename the certificate and the key on FMC ? they are not for FMC sftunnel . They are for FTD only. On the FTD: 1. In the /var/sf/peers// directory, move the old files sftunnel-cert.pem and sftunnel-cert.pem or rename them. 2. Place the FMC issued new certificate file under this directory. 3. Restart sftunnel process on the FTD.

Further Problem Description