How to Scan MSG Files for Malware and Other Threats in Node.js

Cloudmersive
3 min readApr 17, 2024

MSG files can play host to a variety of malicious attachments. When we store MSG files, we store attachments with them; thus, we should always scan MSG files for threats before we share them or upload them elsewhere.

We can perform a quick and effective malware & content threat scan using the ready-to-run Node.js code examples provided below. We’ll call a free API that checks for virus and malware signatures while additionally looking for executables, macros, embedded images, HTML, and other potential content threats stored within the file.

To begin structuring our API call, we can install the SDK via NPM install:

npm install cloudmersive-virus-api-client --save

Alternatively, we can add the following snippet to our package.json:

  "dependencies": {
"cloudmersive-virus-api-client": "^1.1.9"
}

After that, we can turn our attention to API call authorization. With a free Cloudmersive API key, we’ll be able to make up to 800 API calls per month with no commitments.

With our API key ready, we can now call the function using the below code examples. We can set custom threat rules (via request parameters) to flag certain threatening content types along with malware:

var CloudmersiveVirusApiClient = require('cloudmersive-virus-api-client');
var defaultClient = CloudmersiveVirusApiClient.ApiClient.instance;

// Configure API key authorization: Apikey
var Apikey = defaultClient.authentications['Apikey'];
Apikey.apiKey = 'YOUR API KEY';



var apiInstance = new CloudmersiveVirusApiClient.ScanApi();

var inputFile = Buffer.from(fs.readFileSync("C:\\temp\\inputfile").buffer); // File | Input file to perform the operation on.

var opts = {
'allowExecutables': true, // Boolean | Set to false to block executable files (program code) from being allowed in the input file. Default is false (recommended).
'allowInvalidFiles': true, // Boolean | Set to false to block invalid files, such as a PDF file that is not really a valid PDF file, or a Word Document that is not a valid Word Document. Default is false (recommended).
'allowScripts': true, // Boolean | Set to false to block script files, such as a PHP files, Python scripts, and other malicious content or security threats that can be embedded in the file. Set to true to allow these file types. Default is false (recommended).
'allowPasswordProtectedFiles': true, // Boolean | Set to false to block password protected and encrypted files, such as encrypted zip and rar files, and other files that seek to circumvent scanning through passwords. Set to true to allow these file types. Default is false (recommended).
'allowMacros': true, // Boolean | Set to false to block macros and other threats embedded in document files, such as Word, Excel and PowerPoint embedded Macros, and other files that contain embedded content threats. Set to true to allow these file types. Default is false (recommended).
'allowXmlExternalEntities': true, // Boolean | Set to false to block XML External Entities and other threats embedded in XML files, and other files that contain embedded content threats. Set to true to allow these file types. Default is false (recommended).
'allowInsecureDeserialization': true, // Boolean | Set to false to block Insecure Deserialization and other threats embedded in JSON and other object serialization files, and other files that contain embedded content threats. Set to true to allow these file types. Default is false (recommended).
'allowHtml': true, // Boolean | Set to false to block HTML input in the top level file; HTML can contain XSS, scripts, local file accesses and other threats. Set to true to allow these file types. Default is false (recommended) [for API keys created prior to the release of this feature default is true for backward compatability].
'restrictFileTypes': "restrictFileTypes_example" // String | Specify a restricted set of file formats to allow as clean as a comma-separated list of file formats, such as .pdf,.docx,.png would allow only PDF, PNG and Word document files. All files must pass content verification against this list of file formats, if they do not, then the result will be returned as CleanResult=false. Set restrictFileTypes parameter to null or empty string to disable; default is disabled.
};

var callback = function(error, data, response) {
if (error) {
console.error(error);
} else {
console.log('API called successfully. Returned data: ' + data);
}
};
apiInstance.scanFileAdvanced(inputFile, opts, callback);

Now we can easily perform a quick, effective threat scan on MSG files with just a few lines of Node.js code.

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