Technical Tip: Log forwarding to rsyslog server over TLS (OpenSSL)

[tnesh]

Description	This article describes how to forward FortiGate logs from FortiAnalyzer to rsyslog server over TLS. OpenSSL will be used to generate the CA and Server certificate.
Scope	FortiAnalyzer, rsyslog server.
Solution	Generate CA and local/server certificate using OpenSSL: CA key: Linux # openssl genrsa -out rootCA.key 4096 CA Certificate: Linux # openssl req -x509 -new -nodes -key rootCA.key -sha512 -days 3650 -out rootCA.pem Server key: Linux # openssl genrsa -out syslog.key 2048 Server certificate: Linux # openssl req -new -key syslog.key -out syslog.csr Linux # openssl x509 -req -in syslog.csr -CA rootCA.pem -CAkey rootCA.key -out syslog.crt -days 365 -CAcreateserial View server certificate: Linux # openssl x509 -test -noout -in syslog.crt Update the rsyslog config file: Linux # vi /etc/rsyslog.con  # set certificate files global( DefaultNetstreamDriverCAFile="/etc/pki/tls/syslog_cert/rootCA.pem" DefaultNetstreamDriverCertFile="/etc/pki/tls/syslog_cert/syslog.crt" DefaultNetstreamDriverKeyFile="/etc/pki/tls/syslog_cert/syslog.key" ) # load TCP listener module( load="imtcp" StreamDriver.Name="ossl" StreamDriver.Mode="1" StreamDriver.Authmode="x509/certvalid" ) # start up listener at port 6514 input( type="imtcp" port="6514" ) Import the CA & local/server certificate to FortiAnalyzer: Certificate FortiAnalyzer -> System Settings -> Certificates -> Import rootCA.pem CA Certificate (Local CA Certificate) syslog.crt syslog.key Certificate -> Certificate (Local Certificate). Configure FortiAnalyzer log forwarding settings: FAZ # config system log-forward     edit 1         set mode forwarding         set fwd-max-delay realtime         set server-name "rsyslog-server"         set server-addr "thi-centos.fortilab.com"         set server-port 6514         set fwd-server-type syslog         set fwd-server-type syslog         set fwd-reliable enable         set fwd-secure enable         set peer-cert-cn "thi-centos.fortilab.com"     next end If 'peer-cert-cn' is unset/(null), FortiAnalyzer will not check for peer-cert-cn during negotiation: 'peer-cert-cn' is optional, not mandatory. If 'peer-cert-cn' is set: Make sure it is set to the correct server certificate CN value. Before configuring 'certificate oftp', perform the following in FortiGate to ensure FortiAnalyzer receives the FortiGate log successfully: Import the CA certificate that signs the local/server certificate to all the connected FortiGate. Disable 'certificate-verification' in the FortiAnalyzer setting. Configure 'certificate oftp' in FortiAnalyzer: FAZ # config system certificate oftp     set mode local     set local syslog end If 'certificate oftp' is not set to the correct server certificate, rsyslog will prompt 'Certificate error': Linux # sudo journalctl -f -u rsyslog   If 'certificate oftp' is set but FortiGate does not have a CA certificate or 'certificate-verification' is enabled, 'exe log fortianalyzer test-connectivity' in FortiGate will show 'log not received'.   Restart oftpd and logfwd daemon in FortiAnalyzer: FAZ # diagnose test application oftpd 99 FAZ # diagnose test application logfwd 99 Verify the connections: FortiAnalyzer connection to FortiGate: FAZ # diagnose test application oftpd 3 FGT # exec log fortianalyzer test-connectivity FortiAnalyzer logs forwarding to the rsyslog server: FAZ # diagnose test application logfwd 4 Related articles: Technical Tip : Generate and sign certificates using OpenSSL in Windows OS for VPN  Troubleshooting Tip: FortiGate to FortiAnalyzer connectivity Technical Tip: How to configure and troubleshoot Log Forwarding on FortiAnalyzer