How to Detect Insecure Deserialization in File Uploads using Node.js

Cloudmersive
3 min readMay 16, 2023

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Object serialization files are run-of-the-mill and typically harmless. In some cases, however, client-side threat actors can inject malicious references into our data to exploit a weakly configured data parser. The consequences of successful insecure deserialization attempts can be very severe; as a result, it’s good practice to thoroughly scan the contents of object serialization files and block those containing unexpected references.

Using the free API provided below, you can easily detect and block Insecure Deserialization attempts within object serialization files. In addition, you can scan all your file uploads for viruses and malware, leveraging a growing list of more than 17 million threat signatures. To get up and running, you can copy ready-to-run Node.js code examples directly into your environment and you’ll be done in minutes.

Start by installing the client SDK using npm install:

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

Then copy the code examples below to structure your API call:

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 you can set the allowInsecureDeserialization request parameter to “False,” which will return a CleanResult: False response for all files containing insecure deserialization within their contents.

To authenticate your request, supply a free-tier API key (which is good for 800 API calls per month).

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Cloudmersive
Cloudmersive

Written by Cloudmersive

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