Check MaxPasswordAge in Windows with local C# application

Question

I am having the worst time trying to find documentation of this on the internet. Essentially I want to know that Secpol MaXPWAge is set to 90 or less and have it display in a textbox (let's call it textbox1 for ease) I have searched WMI solution, registry, GPEDIT in auditor and have found nothing. I did find this, but honestly, I have no clue how to use the same code to check the Max Password Age instead of complexity requirements. PLEASE, can someone show me what I should be doing here? C# is not my primary language.

https://gist.github.com/jkingry/421802

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        Console.Write(PasswordComplexityPolicy());
    }

    static bool PasswordComplexityPolicy()
    {
        var tempFile = Path.GetTempFileName();

        Process p = new Process();
        p.StartInfo.FileName = Environment.ExpandEnvironmentVariables(@"%SystemRoot%\system32\secedit.exe");
        p.StartInfo.Arguments = String.Format(@"/export /cfg ""{0}"" /quiet", tempFile);
        p.StartInfo.CreateNoWindow = true;
        p.StartInfo.UseShellExecute = false;
        p.Start();
        p.WaitForExit();

        var file = IniFile.Load(tempFile);

        IniSection systemAccess = null;
        var passwordComplexityString = "";
        var passwordComplexity = 0;

        return file.Sections.TryGetValue("System Access", out systemAccess)
            && systemAccess.TryGetValue("PasswordComplexity", out passwordComplexityString)
            && Int32.TryParse(passwordComplexityString, out passwordComplexity)
            && passwordComplexity == 1;
    }

    class IniFile
    {
        public static IniFile Load(string filename)
        {
            var result = new IniFile();
            result.Sections = new Dictionary<string, IniSection>();
            var section = new IniSection(String.Empty);
            result.Sections.Add(section.Name, section);

            foreach (var line in File.ReadAllLines(filename))
            {
                var trimedLine = line.Trim();
                switch (line[0])
                {
                    case ';':
                        continue;
                    case '[':
                        section = new IniSection(trimedLine.Substring(1, trimedLine.Length - 2));
                        result.Sections.Add(section.Name, section);
                        break;
                    default:
                        var parts = trimedLine.Split('=');
                        if(parts.Length > 1)
                        {
                            section.Add(parts[0].Trim(), parts[1].Trim());
                        }
                        break;
                }                    
            }

            return result;
        }

        public IDictionary<string, IniSection> Sections { get; private set; }
    }

    class IniSection : Dictionary<string, string>
    {
        public IniSection(string name) : base(StringComparer.OrdinalIgnoreCase)
        {
            this.Name = name;
        }

        public string Name { get; private set; }
    }
}

Answer 1

This is kind of a cheat, but it works if you're only looking for that one thing. Basically it starts a new process and runs net accounts, then scapes the Maximum password age field from the output. Try it out, but you might have to run it as an administrator:

var process = new Process
{
    StartInfo = new ProcessStartInfo()
    {
        FileName = "net",
        Arguments = "accounts",
        UseShellExecute = false,
        RedirectStandardOutput = true,
        CreateNoWindow = true
    }
};

process.Start();
string text = "";
while (!process.StandardOutput.EndOfStream)
{
    text = process.StandardOutput.ReadLine();
    if (text != null && text.StartsWith("Maximum password age (days):"))
        break;
}
if (text == null || !text.StartsWith("Maximum password age (days):"))
    return;
text = text.Replace("Maximum password age (days):", "").Trim();

textBox1.Text = text;

Answer 2

I would write the IniFile class like this:

class IniFile : Dictionary<string,Dictionary<string,string>> {
    public IniFile(string filename) {
        var currentSection = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        Add("", currentSection);
        foreach (var line in File.ReadAllLines(filename)) {
            var trimedLine = line.Trim();
            switch (line[0]) {
                case ';':
                    continue;
                case '[':
                    currentSection = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
                    Add(trimedLine.Substring(1, trimedLine.Length - 2), currentSection);
                    break;
                default:
                    var parts = trimedLine.Split('=');
                    if (parts.Length > 1) {
                        currentSection.Add(parts[0].Trim(), parts[1].Trim());
                    }
                    break;
            }
        }
    }
    public string this[string sectionName, string key] {
        get {
            Dictionary<string, string> section;
            if (!TryGetValue(sectionName, out section)) { return null; }
            string value;
            if (!section.TryGetValue(key, out value)) { return null; }
            return value;
        }
    }
    public int? GetInt(string sectionName, string key) {
        string stringValue = this[sectionName, key];
        int result;
        if (!int.TryParse(stringValue, out result)) { return null; }
        return result;
    }
}

and put the ini file generation into a separate method:

class Program {
    static void GenerateSecEditOutput(out string tempFile) {
        tempFile = Path.GetTempFileName();
        var p = new Process {
            StartInfo = new ProcessStartInfo {
                FileName = Environment.ExpandEnvironmentVariables(@"%SystemRoot%\system32\secedit.exe"),
                Arguments = String.Format(@"/export /cfg ""{0}"" /quiet", tempFile),
                CreateNoWindow = true,
                UseShellExecute = false
            }
        };
        p.Start();
        p.WaitForExit();
    }

    //... Main goes here
}

Then, the Main method looks like this:

static void Main(string[] args) {
    //This will be the path of the temporary file which contains the output of secedit.exe
    string tempFile;

    //Write the output of secedit.exe to the temporary file
    GenerateSecEditOutput(out tempFile);

    //Parse the temporary file
    var iniFile = new IniFile(tempFile);

    //Read the maximum password age from the "System Access" section
    var maxPasswordAge = iniFile.GetInt("System Access", "MaximumPasswordAge");
    if (maxPasswordAge.HasValue) {
        Console.WriteLine("MaxPasswordAge = {0}", maxPasswordAge);
    } else {
        Console.WriteLine("Unable to find MaximumPasswordAge");
    }
    Console.ReadKey(true);
}

If you have some textbox you want to put the value into, the steps are more or less the same. We can avoid the integer parsing, and use the indexer of IniFile:

string tempFile;
GenerateSecEditOutput(out tempFile);
var iniFile = new IniFile(tempFile);
//assuming tb is a variable referring to a textbox
tb.Text = iniFile["System Access", "MaximumPasswordAge"];

Keep in mind that secedit.exe requires admin permissions to run. Without admin permissions, the code won't fail; the temporary file will simply be empty. See here for some suggestions on how to do this.