Programmatically getting an executable's Certificate Details

In Powershell:

Get-AuthenticodeSignature C:PathTOFile.exe

So, using your example of explorer.exe this would get Redmond:

(Get-AuthenticodeSignature C:Windowsexplorer.exe).SignerCertificate.subject.split(',')[2].split('=')[1]

Since you asked for elaboration, Get-AuthenticodeSignature returns a System.Management.Automation.Signature object. You can find this out a few ways. Personally I prefer to assign it to a variable so I can play around with the returned object further. Once you have it assigned to a variable you can learn things about it. Get-Member should be one of your go to cmdlets in Powershell. In this case:

$foo = Get-AuthenticodeSignature C:Windowsexplorer.exe
Get-Member -InputObject $foo
   TypeName: System.Management.Automation.Signature

Name                   MemberType Definition
----                   ---------- ----------
Equals                 Method     bool Equals(System.Object obj)
GetHashCode            Method     int GetHashCode()
GetType                Method     type GetType()
ToString               Method     string ToString()
IsOSBinary             Property   bool IsOSBinary {get;}
Path                   Property   string Path {get;}
SignatureType          Property   System.Management.Automation.SignatureType SignatureType {get;}
SignerCertificate      Property   System.Security.Cryptography.X509Certificates.X509Certificate2 SignerCertificate {...
Status                 Property   System.Management.Automation.SignatureStatus Status {get;}
StatusMessage          Property   string StatusMessage {get;}
TimeStamperCertificate Property   System.Security.Cryptography.X509Certificates.X509Certificate2 TimeStamperCertific...

So you can see that the object has some methods and some properties (I know, all objects do). In this case the methods are all the standard ones that are inherited from System.Object. The properties though are interesting. The SignerCertificate looks like what you wanted so let's see what that looks like:

$foo.SignerCertificate


Thumbprint                                Subject
----------                                -------
419E77AED546A1A6CF4DC23C1F977542FE289CF7  CN=Microsoft Windows, O=Microsoft Corporation, L=Redmond, S=Washington, C=US

The thumbrint is obviously important because it is what identifies the cert but you had asked about the Redmond that is in the subject. So now we know how to get to that as a string:

$foo.SignerCertificate.Subject

So it is just straight string parsing from here.

One more tidbit that I will throw in since it seems you may be learning Powershell. Another cmdlet that you should try regularly is Get-Command. In this case I did not even know that the Get-AuthenticodeSignature cmdlet existed before you asked the question. So I did this:

Get-Command *signature*

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Function        Update-MpSignature                                 1.0        Defender
Cmdlet          Get-AuthenticodeSignature                          3.0.0.0    Microsoft.PowerShell.Security
Cmdlet          Save-VolumeSignatureCatalog                        1.0.0.0    ShieldedVMDataFile
Cmdlet          Set-AuthenticodeSignature                          3.0.0.0    Microsoft.PowerShell.Security