Can Executable Files Contain Viruses?

Cloudmersive
3 min readSep 18, 2023

So, you’ve noticed a suspicious .EXE file hanging around in one of your most sensitive cloud storage locations. Could this file have bypassed your antivirus policies & now pose an immediate threat to your system?

In short, the answer is yes — it certainly could. Executables are a commonly used file type for disguising viruses and malware, and opening an infected executable can quickly infect your computer.

Detecting Executables

Thankfully, it’s possible to implement solutions that both identify virus & malware signatures AND allow you to block verified content types that you don’t want to have hanging around.

Using the below Node.js code examples, you can take advantage of a free Virus Scan API that allows you to set custom threat rules against Executables and a variety of other dangerous file types.

Let’s first run the following command to install the Virus API client:

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

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

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

Finally, let’s copy the below code examples to structure our API call. We’ll need to provide a free-tier API key to make up to 800 API calls per month with no commitments:

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 protect applications and storage locations from virus & malware signatures and/or block Executable files entirely.

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