Authenticode-JS

Authenticode-JS is a fully NodeJS tool that can sign, unsign, timestamp and change version and icon resources in a Windows executables. You can also get information about an executable signature and generate your own code signing certificate.

This module can be useful when wanting to sign windows executable on non-windows platforms, like signing a Windows executable on Linux or macOS. This code is used by MeshCentral to code-sign the agent on each installed server.

Using as a command line tool

You can run authenticode.js as a command line tool like this:

node authenticode

You will see this:

MeshCentral Authenticode Tool.
Usage:
  node authenticode.js [command] [options]
Commands:
  info: Show information about an executable.
          --exe [file]               Required executable to view information.
          --json                     Show information in JSON format.
  sign: Sign an executable.
          --exe [file]               Required executable to sign.
          --out [file]               Resulting signed executable.
          --pem [pemfile]            Certificate & private key to sign the executable with.
          --desc [description]       Description string to embbed into signature.
          --url [url]                URL to embbed into signature.
          --hash [method]            Default is SHA384, possible value: MD5, SHA224, SHA256, SHA384 or SHA512.
          --time [url]               The time signing server URL.
          --proxy [url]              The HTTP proxy to use to contact the time signing server, must start with http://
  unsign: Remove the signature from the executable.
          --exe [file]               Required executable to un-sign.
          --out [file]               Resulting executable with signature removed.
  createcert: Create a code signging self-signed certificate and key.
          --out [pemfile]            Required certificate file to create.
          --cn [value]               Required certificate common name.
          --country [value]          Certificate country name.
          --state [value]            Certificate state name.
          --locality [value]         Certificate locality name.
          --org [value]              Certificate organization name.
          --ou [value]               Certificate organization unit name.
          --serial [value]           Certificate serial number.
  timestamp: Add a signed timestamp to an already signed executable.
          --exe [file]               Required executable to timestamp.
          --out [file]               Resulting signed executable.
          --time [url]               The time signing server URL.
          --proxy [url]              The HTTP proxy to use to contact the time signing server, must start with http://
  icons: Show the icon resources in the executable.
          --exe [file]               Input executable.
  saveicon: Save a single icon bitmap to a .ico file.
          --exe [file]               Input executable.
          --out [file]               Resulting .ico file.
          --icon [number]            Icon number to save to file.
  saveicons: Save an icon group to a .ico file.
          --exe [file]               Input executable.
          --out [file]               Resulting .ico file.
          --icongroup [groupNumber]  Icon groupnumber to save to file.

Note that certificate PEM files must first have the signing certificate,
followed by all certificates that form the trust chain.

When doing sign/unsign, you can also change resource properties of the generated file.

          --fileversionnumber n.n.n.n
          --productversionnumber n.n.n.n
          --filedescription [value]
          --fileversion [value]
          --internalname [value]
          --legalcopyright [value]
          --originalfilename [value]
          --productname [value]
          --productversion [value]
          --removeicongroup [number]
          --icon [groupNumber],[filename.ico]

Using as a module

You can use authenticode-js in your code as an external module. To load an exectuable call createAuthenticodeHandler. This call will return null if the executable can't be loaded or is invalid.

var exehandler = require("authenticode").createAuthenticodeHandler("/tmp/windowsexecutable.exe");

You can then get information about the existing signature of this executable:

console.log(exehandler.header);            // Display executable header information.
console.log(exehandler.fileHashAlgo);      // Display the type of hashing used, typically 'sha256' or 'sha384'.
console.log(exehandler.fileHashSigned);    // Display the hash included in the signature.
console.log(exehandler.fileHashActual);    // Display the actual hash of the file.
console.log(exehandler.signingAttribs);    // DIsplay any signing attributes, typically description and/or url.

You can remove the signature of an executable like this:

exehandler.unsign({ out: '/tmp/windowsexecutable-unsigned.exe' });

You can sign or re-sign an exectuable and timestamp it. You can load the certificate PEM file using the built in loadcertificate() method, or you can pass null as the certificate and a test certificate will be generated and used to sign the executable. The desc and url options are optional.

const cert = require("authenticode").loadCertificates("/tmp/signingcert.pem");
exehandler.sign(cert, { out: '/tmp/windowsexecutable-signed.exe', desc: "description", url: "https://sample.org", time: "http://timestamp.sectigo.com" });

You can generate your own code signing certificate. All of the certificate creation values are optional, but cn should really be present. Oddly, the serial number should be an integer that starts with a single leading 0, for example 0123 or 01111. Once created, you can use node-forge to save the certificate.

const cert = require("authenticode").createSelfSignedCert({ cn: "commonName", serial: "012345", state: "state", locality: "locality", country: "x", org: "org", orgunit: "orgunitf" });
require('fs').writeFileSync("/tmp/signingcert.pem", require('node-forge').pki.certificateToPem(cert.cert) + '\r\n' + require('node-forge').pki.privateKeyToPem(cert.key));

Certificate file format

In the above examples, a signingcert.pem file contains the certificate and private key used to sign the windows executable. The format of this .pem file is as follows:

This is the code signing public certificate, must be first.
-----BEGIN CERTIFICATE-----
MIIEQDCC...
-----END CERTIFICATE-----

This is the code signing certificate private key, can be anywhere in the file.
-----BEGIN RSA PRIVATE KEY-----
MIIG5AIB...
-----END RSA PRIVATE KEY-----

This is one of the public certificate in the validation chain.
-----BEGIN CERTIFICATE-----
MIIEQzCCA...
-----END CERTIFICATE-----

This is another public certificate in the validation chain, you can put as many as needed.
-----BEGIN CERTIFICATE-----
MIIEQzCCA...
-----END CERTIFICATE-----

License

This software is licensed under Apache 2.0.