Microsoft Azure Sentinel (om_azure)

This module can be used to forward logs to Microsoft Azure applications. It can operate in three different modes to connect to the following data sources:

Azure Table Storage
Azure Blob Storage
Azure Log Analytics workspace

It will connect to the URL specified in the configuration in either plain HTTP or HTTPS mode. Event data is sent in batches, reducing the latency caused by the HTTP responses, thus improving Microsoft Azure’s server performance.

To examine the supported platforms, see the list of installation packages.

Storage setup

For Blob or Table modes, Azure web application logging and storage can be configured from the Azure Management Portal by following these steps:

After logging in to the Portal, open the left portal menu, select Storage accounts, and then select Create.
Create the new storage account, providing a storage account name, region, and redundancy type. Take note of the storage name, you will need to specify this value in the NXLog Agent configuration. More information on the storage settings can be found in the Microsoft documentation on how to Create a storage account.
On the Review + create tab, click Create and wait for storage setup to complete.
Navigate to your app and select App Service logs.
Select On for Application Logging (Blob).
Configure Storage Settings corresponding with the storage account created above. More information on the configuration settings can be found in the Microsoft documentation on how to Enable diagnostic logging for apps.
Confirm the changes by clicking Save, then restart the service. Note that it may take a while for Azure to create the table and/or blob in the storage.

Log Analytics workspace setup

For Analytics mode, an application needs to be registered and granted the necessary permissions to read from the Log Analytics workspace. Follow the instructions to Register an application in Microsoft Entra ID.

Grant the application permission to use the Log Analytics API and create a client secret:

From the left menu, select API permissions and then + Add a permission. Select APIs my organization uses and choose Log Analytics API.
Select Application permissions for the type of permission required, and Data.Read for the permission.
Click Add permissions to create the permission.
From the left menu, select Certificates & secrets and then + New client secret. Enter a description and expiration period, then click Add.
Take note of the Value of the new secret, you will need to specify this for the SharedKey directive.

Add the app to your Log Analytics workspace:

Go to your Log Analytics workspace and take note of the Workspace ID. You will need to specify this value for the WorkspaceID directive.
From the left menu, select Access control (IAM). Click + Add and select Add role assignments.
Choose Log Analytics Reader for role, select the application registered above, and click Save.

Output log format

om_azure in Table and Analytics modes forwards log records over HTTP(S) as JSON payload. The JSON format depends on the value of the $raw_event field. The module checks if the value of $raw_event is valid JSON and applies the following rules:

If it is valid JSON, the value is forwarded as is.
If it is not valid JSON, the log record is converted to JSON in the following format:
```
{
  "raw_event": "<json_escaped_raw_event>"
}
```

Additional metadata, including the NXLog Agent-specific fields EventReceivedTime, SourceModuleName, and SourceModuleType, will not be included in the output unless these values have been written to the $raw_event field. The processing required to achieve this depends on the format of the input data, but generally, it means you need to:

Parse the log record according to the data format.
- If the input data is already in JSON format, use parse_json() to parse $raw_event into fields.
- If the input is unstructured plain text data, copy the value of $raw_event to a custom field.
Create and populate any additional custom fields.
Use to_json() to convert the fields to JSON format and update the value of $raw_event.

See the Examples section for NXLog Agent configuration examples of the above.

Configuration

The om_azure module accepts the following directives in addition to the common module directives.

Required directives

The following directive is required for the module to start.

Mode

This directive specifies the type of service the module should connect to. It accepts one of the following values: Table, Blob, or Analytics. The default is Analytics for backward compatibility. Each mode requires a corresponding set of mandatory directives.

Table mode

The following directives are required when using Table mode.

SharedKey

This directive specifies the authentication key to use for connecting to the Azure Storage account.

StorageName

This directive specifies the name of the storage account to connect to.

TableName

The module will forward logs to this storage table. It must be a string-type expression. If the expression is not a constant string, i.e., it contains functions, field names, or operators, it will be evaluated for each event. If a table with the specified name doesn’t exist, om_azure will create it. The table name must only include letters and numbers. An expression that results in an invalid table name will cause an error and prevent events from being forwarded.

Blob mode

The following directives are required when using Blob mode.

Blob

This directive specifies the path of a single blob (formatted as container/blob) to which the module should forward logs. It must be a string-type expression. If the expression is not a constant string, i.e., it contains functions, field names, or operators, it will be evaluated for each event. If neither a blob container nor a blob with the specified name exists, om_azure will create it. An expression must result in a string with the container and blob name separated by the / character.

SharedKey

This directive specifies the authentication key to connect to the Azure Storage account.

StorageName

This directive specifies the name of the storage account to connect to.

Analytics mode

The following directives are required when using Analytics mode.

SharedKey

This directive specifies the authentication key to connect to the Azure Storage account.

TableName

This directive specifies the name of a Custom Table that the module will send the logs to. Azure automatically appends _CL to all Custom Tables, thus the table will appear as TableName_CL in the list of Custom Tables. It must be a string-type expression. If the expression is not a constant string, i.e., it contains functions, field names, or operators, it will be evaluated for each event.

URL

This directive specifies the URL that the module will connect to. The module works in a failover configuration if additional URL directives are specified on new lines. If the first URL is unreachable, the module automatically fails over to the next one. If the last URL is unreachable, the module fails over to the first URL.

The module operates in plain HTTP or HTTPS mode depending on the URL provided. If the port number is not explicitly defined, it defaults to port 80 for HTTP and port 443 for HTTPS.

WorkspaceID

This directive specifies the workspace ID of the Log Analytics account.

HTTPS directives

The following directives configure secure data transfer via HTTPS.

HTTPSAllowExpired

Set this directive to TRUE to allow connections with remote hosts presenting an expired certificate. The default is FALSE; the module rejects connections with expired certificates. This directive only takes effect when HTTPSRequireCert is set to TRUE.

HTTPSAllowHostnameValidation

Set this directive to TRUE to require that the certificate FQDN matches the server hostname before allowing a connection. The default is FALSE; the module does not validate the remote server hostname.

HTTPSAllowUntrusted

Set this directive to TRUE to allow connections with remote hosts regardless of certificate verification results. The default is FALSE; the module only accepts connections with trusted certificates.

HTTPSCADir

Set this directive to the path of a directory containing Certificate Authority (CA) certificates. The module uses these certificates to verify the certificate presented by the remote host. Name the certificate files using the OpenSSL hashed format: the hash of the certificate followed by .0, .1, and so on. To find the hash of a certificate using OpenSSL:

$ openssl x509 -hash -noout -in ca.crt

For example, if the certificate hash is e2f14e4a, name the certificate file e2f14e4a.0. If there is another certificate with the same hash, name it e2f14e4a.1, and so on.

To trust a remote host’s self-signed certificate, include a copy of it in this directory.

If this directive isn’t specified, NXLog Agent falls back to the default operating system root certificate store. Unix-like operating systems commonly store root certificates in /etc/ssl/certs. Windows operating systems use the Windows Certificate Store, while macOS uses the Keychain Access Application as the default certificate store. See Certificate Authority (CA) certificates in the NXLog Platform User Guide for more information on using this directive.

In addition, Microsoft’s PKI repository contains root certificates for Microsoft services.

This directive is mutually exclusive with the HTTPSCAThumbprint, HTTPSCAPattern, and HTTPSSearchAllCertStores directives.

HTTPSCAFile

Set this directive to the path of the Certificate Authority (CA) certificate used to verify the certificate presented by the remote host. To trust a remote host’s self-signed certificate, specify the remote host’s certificate itself. For certificates signed by an intermediate CA, the specified certificate must contain the complete certificate chain (certificate bundle).

This directive is mutually exclusive with the HTTPSCAThumbprint, HTTPSCAPattern, and HTTPSSearchAllCertStores directives.

HTTPSCAPattern

Set this directive to a PCRE2-compliant regular expression to locate a suitable Certificate Authority (CA) certificate. This directive is supported on Windows and macOS.

On Windows, the certificate must be in the Windows Certificate Store. On macOS, the certificate must be in the system keychain.

NXLog Agent matches the pattern against a string built from the certificate’s fields in this order:

SUBJECT=<value>, CN=<value>; DN=CN=<value>, O=<value>, OU=<value>, L=<value>, ST=<value>, C=<value>; SAN=<value>

The pattern doesn’t need to match every field. Include only the fields you want to match, and use .*? to skip over the rest.

For example, the following pattern matches only the DN and SAN fields:

HTTPSCAPattern    'DN=CN=SERVER01\.example\.com.*?SAN=DNS:SERVER01\.example\.com'

This produces the following output in the NXLog Agent log file:

matching pattern [DN=CN=SERVER01\.example\.com;.*?SAN=DNS:SERVER01\.example\.com] to certificate [SUBJECT=US, ClientState, ClientCity, ClientCompany, ClientUnit, SERVER01.example.com, CN=SERVER01.example.com; DN=CN=SERVER01.example.com, O=ClientCompany, OU=ClientUnit, L=ClientCity, ST=ClientState, C=US; SAN=DNS:SERVER01.example.com; DNS:www.SERVER01.example.com; IP:127.0.0.3; ]

If the pattern matches multiple certificates, NXLog Agent uses the first match. If the certificate changes, restart NXLog Agent to apply the new certificate.

This directive is mutually exclusive with the HTTPSCAThumbprint, HTTPSCADir, HTTPSCAFile, and HTTPSSearchAllCertStores directives.

On macOS, keychain behavior and certificate requirements depend on your operating system version. Newer versions enforce stricter rules on certificate algorithms and key sizes. A certificate and private key may be imported into the keychain, yet remain unusable if they do not comply with the current macOS requirements. After importing, you may also need to give NXLog Agent permission to use the certificate in the keychain.

Check your operating system documentation to find out which certificates are trusted and valid. See also Apple’s certificate requirements for macOS.

HTTPSCAThumbprint

Set this directive to the thumbprint of the Certificate Authority (CA) certificate used to verify the certificate presented by the remote host. This directive is supported on Windows and macOS.

On Windows, copy the hexadecimal fingerprint string from Windows Certificate Manager (certmgr.msc). The certificate must be in a Windows certificate store accessible by NXLog Agent.

On macOS, obtain the hexadecimal fingerprint string from the Keychain Access application. The certificate must be accessible in the system keychain.

Whitespaces and colons are automatically removed.

This directive is mutually exclusive with the HTTPSCADir, HTTPSCAFile, HTTPSCAPattern, and HTTPSSearchAllCertStores directives.

Check your operating system documentation to find out which certificates are trusted and valid. See also Apple’s certificate requirements for macOS.

HTTPSCertFile

Set this directive to the path of the certificate file to present to the remote host during the HTTPS handshake.

HTTPSCertKeyFile

Set this directive to the path of the private key file corresponding to the certificate specified by HTTPSCertFile.

HTTPSCertPattern

Set this directive to a PCRE2-compliant pattern to identify the certificate and its corresponding private key. This directive is supported on Windows and macOS.

NXLog Agent matches the pattern against a string built from the certificate’s fields in this order:

SUBJECT=<value>, CN=<value>; DN=CN=<value>, O=<value>, OU=<value>, L=<value>, ST=<value>, C=<value>; SAN=<value>

The pattern doesn’t need to match every field. Include only the fields you want to match, and use .*? to skip over the rest.

On Windows, import the certificate in PFX format into the Local Computer\Personal certificate store.

On macOS, ensure the certificate and its private key are present in the System Keychain (/Library/Keychains/System.keychain).

During configuration, NXLog Agent resolves this directive into the corresponding HTTPSCertThumbprint value. If the pattern matches multiple certificates, NXLog Agent uses the first match. This directive is not dynamic; restart NXLog Agent to apply a changed certificate.

We recommend keeping the certificate storage referenced by this directive well-maintained for optimal performance.

This directive is mutually exclusive with the HTTPSCertThumbprint, HTTPSCertFile and HTTPSCertKeyFile directives.

Configuration examples:

HTTPSCertPattern    $hostname + 'Cert'

HTTPSCertPattern    DN=CN=Client\.example\.com;.*?SAN=DNS:Client\.example\.com

This produces the following output in the NXLog Agent log file:

matching pattern [DN=CN=Client\.example\.com;.*?SAN=DNS:Client\.example\.com] to certificate [SUBJECT=US, ClientState, ClientCity, ClientCompany, ClientUnit, Client.example.com, CN=Client.example.com; DN=CN=Client.example.com, O=ClientCompany, OU=ClientUnit, L=ClientCity, ST=ClientState, C=US; SAN=DNS:Client.example.com; DNS:www.Client.example.com; IP:127.0.0.3; ]

Check your operating system documentation to find out which certificates are trusted and valid. See also Apple’s certificate requirements for macOS.

HTTPSCertThumbprint

Set this directive to the thumbprint of the certificate to present to the remote host during the HTTPS handshake. Whitespaces and colons are automatically removed. This directive is supported on Windows and macOS.

On Windows, copy the hexadecimal fingerprint string from Windows Certificate Manager (certmgr.msc). Import the certificate to the Local Computer\Personal certificate store in PFX format. To create a PFX file from the certificate and private key using OpenSSL:

$ openssl pkcs12 -export -out server.pfx -inkey server.key -in server.pem

When the global directive UseCNGCertificates is set to FALSE, the private key must be exportable.

If you generate the certificate request using Windows Certificate Manager, enable the Make private key exportable option from the certificate properties.
If you import the certificate with the Windows Certificate Import Wizard, make sure that the Mark this key as exportable option is enabled.
If you migrate the certificate and associated private key from one Windows machine to another, select Yes, export the private key when exporting from the source machine.

When UseCNGCertificates is set to TRUE, the private key does not need to be exportable. For example, private keys stored on a TPM are always non-exportable.

On macOS, obtain the hexadecimal fingerprint string from the Keychain Access application. The certificate and its associated private key must be present in the System Keychain (/Library/Keychains/System.keychain).

For example:

HTTPSCertThumbprint    7c2cc5a5fb59d4f46082a510e74df17da95e2152

Check your operating system documentation to find out which certificates are trusted and valid. See also Apple’s certificate requirements for macOS.

HTTPSCRLDir

Set this directive to the path of a directory containing certificate revocation list (CRL) files. The module uses these files to reject connections from hosts presenting a revoked certificate. Name the files using the OpenSSL hashed format: the hash of the issuer followed by .r0, .r1, and so on. To find the hash of the issuer of a CRL file using OpenSSL:

$ openssl crl -hash -noout -in crl.pem

For example, if the hash is e2f14e4a, name the file e2f14e4a.r0. If there is another file with the same hash, name it e2f14e4a.r1, and so on.

HTTPSCRLFile

Set this directive to the path of the certificate revocation list (CRL) file used to reject connections from hosts presenting a revoked certificate. To generate a CRL file using OpenSSL:

$ openssl ca -gencrl -out crl.pem

HTTPSDHFile

Set this directive to the path of a file containing Diffie-Hellman parameters for key exchange. Generate the parameters using dhparam(1ssl). If this directive is not set, the module uses default parameters. See the OpenSSL Wiki for further details.

HTTPSKeyPass

Set this directive to the passphrase of the private key specified by HTTPSCertKeyFile. This directive applies only to encrypted private keys.

To generate a private key with Triple DES encryption using OpenSSL:

$ openssl genrsa -des3 -out server.key 2048

HTTPSLoadCertificateChains

Set this directive to TRUE to load the full certificate chain from the PEM file referenced by HTTPSCertFile, which may contain a single certificate or the complete chain. The default is FALSE; the module loads certificates from the operating system certificate store instead.

This directive is only supported on Windows.

HTTPSRequireCert

Set this directive to TRUE to require the remote host to present a certificate during the HTTPS handshake. The module refuses the connection if no certificate is presented. The default is TRUE.

HTTPSSearchAllCertStores

Set this directive to TRUE to load all available Windows certificates into NXLog Agent for use during remote certificate verification. Any required certificates must be in a Windows certificate store accessible by NXLog Agent. This directive is only supported on Windows and is mutually exclusive with the HTTPSCAThumbprint, HTTPSCAPattern, HTTPSCADir, and HTTPSCAFile directives.

HTTPSSSLCipher

Set this directive to override the permitted cipher list for TLSv1.2 and below. Use the format described in the ciphers(1ssl) man page. For example, specify RSA:!COMPLEMENTOFALL to include all ciphers with RSA authentication but exclude ciphers without encryption.

If RSA or DSA ciphers with Diffie-Hellman key exchange are used, set HTTPSDHFile to specify custom Diffie-Hellman parameters.

HTTPSSSLCiphersuites

Set this directive to override the permitted cipher list for TLSv1.3. Use the same format as HTTPSSSLCipher. Refer to the OpenSSL documentation for a list of valid TLS v1.3 cipher suites. The default is:

TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256

HTTPSSSLCompression

Set this directive to TRUE to compress data using zlib when sending over the network. The default is FALSE; the module sends data without compression.

Some Linux distributions, including Debian, provide an OpenSSL library without zlib support. The module emits a warning on startup if compression support is missing. The generic deb/rpm packages are bundled with a zlib-enabled libssl library.

HTTPSSSLProtocol

Set this directive to restrict the TLS/SSL protocols the module accepts. Specify a comma-separated list of the following values: SSLv2, SSLv3, TLSv1, TLSv1.1, TLSv1.2, and TLSv1.3. The default is TLSv1.2 and TLSv1.3. The OpenSSL library shipped by some Linux distributions does not support SSLv2 and SSLv3; these protocols will not work even if specified here.

HTTPSTLSCertLog

Set this directive to TRUE to log the remote host’s certificate details during the HTTPS handshake. When available, the module logs the Subject, Issuer, NotBefore, and NotAfter fields to the NXLog Agent log file. The default is FALSE.

This directive depends on the values of the HTTPSAllowUntrusted and HTTPSRequireCert directives:

HTTPSAllowUntrusted HTTPSRequireCert Outcome

FALSE

Output depends on HTTPSTLSCertLog value

FALSE

TRUE

Output depends on HTTPSTLSCertLog value

TRUE

FALSE

No output regardless of HTTPSTLSCertLog value

TRUE

Output depends on HTTPSTLSCertLog value

Sigalgs

Set this directive to the signature algorithm parameter to pass to the Windows SSL library. Accepted values depend on the available encryption providers. This directive is only supported on Windows.

SNI

Set this directive to the hostname to use for Server Name Indication (SNI) in HTTPS mode. If not set, the module uses the hostname specified in the URL directive.

UseCNGCertificates

Set this directive to TRUE to use the Windows Cryptography API: Next Generation (CNG) to access the private keys of certificates identified by a thumbprint. This directive is only supported on Windows.

Optional directives

AddHeader

This optional directive specifies an additional header to be added to each HTTP request.

HTTPBasicAuthPassword

HTTP basic authentication password. You must also set the HTTPBasicAuthUser directive to use HTTP authentication.

HTTPBasicAuthUser

HTTP basic authentication username. You must also set the HTTPBasicAuthPassword directive to use HTTP authentication.

LocalPort

Set this directive to the local port number to use for the connection, for example to satisfy a firewall rule that expects traffic from a known port. If you do not set this directive, the module uses a random high port number, which a firewall may block.

Attempts to bind to LocalPort may fail because of the required TIME-WAIT delay in closing connections. When this happens, the module writes Address already in use to the NXLog Agent log file. If it persists, it can degrade network performance.

Proxy

This optional directive is used to specify the IP address (or hostname) and port number of the HTTP proxy server to be used. The format is hostname:port. If the port number is ommited, it defaults to 80.

The om_azure module supports HTTP proxying only. SOCKS4/SOCKS5 proxying is not supported.

Reconnect

This optional directive sets the reconnect interval in seconds. If it is set, the module attempts to reconnect in every defined second. If it is not set, the reconnect interval will start at 1 second and doubles on every attempt. If the duration of the successful connection is greater than the current reconnect interval, then the reconnect interval will be reset to 1 sec.

ResponseTimeout

Maximum time (in seconds) the module waits for an HTTP response from Azure after sending data. If no response is received within this interval, the module closes the current TCP connection and initiates a reconnect. This helps prevent the pipeline from stalling indefinitely due to lost or delayed responses.

Valid values: any positive number greater than or equal to 10. Default: 60

TcpSendStallDetect

Set this directive to TRUE to monitor for pipeline backpressure by logging a warning whenever the module cannot send data to the destination. The module writes the following message to the NXLog Agent log file:

TCP send buffer full for <instance_name> - write blocked

The default is FALSE; the module does not check for send stalls.

URL

This optional directive specifies the URL for connecting to the storage account. The module works in a failover configuration if additional URL directives are specified on new lines. If the first URL is unreachable, the module automatically fails over to the next one. If the last URL is unreachable, the module fails over to the first URL.

The module operates in plain HTTP or HTTPS mode depending on the URL provided. If the port number is not explicitly defined, it defaults to port 80 for HTTP and port 443 for HTTPS.

Procedures

The following procedures are exported by om_azure.

add_http_header(type: string name, type: string value);: Dynamically add a custom HTTP header to HTTP requests.
reconnect();: Force a reconnection. This can be used from a Schedule block to periodically reconnect to the server.

Examples

Example 1. Sending unstructured plain text logs to Table Storage

This configuration reads log messages from file and forwards them to table storage. No further processing is done on the log records.

nxlog.conf

<Input file>
    Module            im_file
    File              'log.txt'
</Input>

<Output azure>
    Module            om_azure
    Mode              Table

    StorageName       YOUR_STORAGE_NAME
    SharedKey         YOUR_SHARED_KEY
    TableName         "TableName"

    AddHeader         X-Custom  :  custom-value
    Exec              add_http_header("Y-Dynamic", "dynamic value");
</Output>

Example 2. Sending unstructured plain text logs to Blob Storage

This configuration reads log messages from file and forwards them to blob storage. No further processing is done on the log records.

nxlog.conf

<Input file>
    Module            im_file
    File              'log.txt'
</Input>

<Output azure>
    Module            om_azure
    Mode              Blob

    StorageName       YOUR_STORAGE_NAME
    SharedKey         YOUR_SHARED_KEY
    Blob              "blob_container/blob_name"

    AddHeader         X-Custom  :  custom-value
    Exec              add_http_header("Y-Dynamic", "dynamic value");
</Output>

Example 3. Sending unstructured plain text logs over HTTPS to Log Analytics Workspaces

This configuration reads log messages from file and forwards them via HTTPS to Microsoft Azure Log Analytics Workspaces. No further processing is done on the log records.

nxlog.conf

<Input file>
    Module            im_file
    File              'log.txt'
</Input>

<Output azure>
    Module            om_azure
    Mode              Analytics

    # Since the API uses HTTPS, SSL must be configured
    HTTPSCAFile       %CERTDIR%/ca.pem

    WorkspaceID       YOUR_WORKSPACE_ID
    SharedKey         YOUR_SHARED_KEY

    TableName         "CustomLogs"
    AddHeader         X-Custom  :  custom-value
    Exec              add_http_header("Y-Dynamic", "dynamic value");
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to Microsoft Azure.

{
  "raw_event": "Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded."
}

Example 4. Sending plain text logs with metadata

This configuration reads log records from file and adds a $Hostname metadata field. Log records are converted to JSON using the to_json() procedure of the xm_json module before they are forwarded to Microsoft Azure.

nxlog.conf

<Extension json>
    Module          xm_json
</Extension>

<Input file>
    Module          im_file
    File            '/path/to/log/file'
    Exec            $Hostname = hostname();
    Exec            $Message = $raw_event;
</Input>

<Output azure>
    Module          om_azure
    Mode            Analytics

    # Since the API uses HTTPS, SSL must be configured
    HTTPSCAFile     %CERTDIR%/ca.pem

    WorkspaceID     YOUR_WORKSPACE_ID
    SharedKey       YOUR_SHARED_KEY

    TableName       "testImFileNative_dir"
    Exec            to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to Microsoft Azure.

{
  "EventReceivedTime": "2021-03-24T16:52:20.457348+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "Hostname": "pc1",
  "Message": "Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded."
}

Example 5. Sending structured syslog records

This configuration reads syslog records from file. It uses the parse_syslog() procedure of the xm_syslog module to parse logs into structured data. Log records are then converted to JSON using the to_json() procedure of the xm_json module before they are forwarded to Microsoft Azure.

nxlog.conf

<Extension syslog>
    Module          xm_syslog
</Extension>

<Extension json>
    Module          xm_json
</Extension>

<Input file>
    Module          im_file
    File            '/path/to/log/file'
    Exec            parse_syslog();
</Input>

<Output azure>
    Module          om_azure
    Mode            Analytics

    # Since the API uses HTTPS, SSL must be configured
    HTTPSCAFile     %CERTDIR%/ca.pem

    WorkspaceID     YOUR_WORKSPACE_ID
    SharedKey       YOUR_SHARED_KEY

    TableName       "testImFileNative_dir"
    Exec            to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to Microsoft Azure.

{
  "EventReceivedTime": "2021-03-24T16:30:18.920342+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "SyslogFacilityValue": 1,
  "SyslogFacility": "USER",
  "SyslogSeverityValue": 5,
  "SyslogSeverity": "NOTICE",
  "SeverityValue": 2,
  "Severity": "INFO",
  "Hostname": "pc1",
  "EventTime": "2021-03-24T15:58:53.000000+01:00",
  "SourceName": "systemd",
  "ProcessID": 1452,
  "Message": "tracker-store.service: Succeeded."
}

Example 6. Sending JSON-formatted logs with metadata

This configuration reads JSON-formatted log records from file. It uses the parse_json() procedure of the xm_json module to parse logs into structured data and adds an $EventType metadata field. Log records are then converted back to JSON using the to_json()procedure before they are forwarded to Microsoft Azure.

nxlog.conf

<Extension json>
    Module          xm_json
</Extension>

<Input file>
    Module          im_file
    File            '/path/to/log/file'
    Exec            parse_json();
    Exec            $EventType = "browser-history";
</Input>

<Output azure>
    Module          om_azure
    Mode            Analytics

    # Since the API uses HTTPS, SSL must be configured
    HTTPSCAFile     %CERTDIR%/ca.pem

    WorkspaceID     YOUR_WORKSPACE_ID
    SharedKey       YOUR_SHARED_KEY

    TableName       "testImFileNative_dir"
    Exec            to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

{
  "AccessTime": "2021-03-24T16:30:43.000000+01:00",
  "URL": "https://nxlog.co",
  "Title": "High Performance Log Collection Solutions",
  "Username": "user1"
}

Output sample

The following is the JSON-formatted log record that will be sent to the Microsoft Azure Sentinel server.

{
  "EventReceivedTime": "2021-03-24T17:14:23.908155+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "AccessTime": "2021-03-24T16:30:43.000000+01:00",
  "URL": "https://nxlog.co",
  "Title": "High Performance Log Collection Solutions",
  "Username": "user1",
  "EventType": "browser-history"
}