Verify if password is correct - c#

i need to verify if the password is correct for a user.
i have this code:
private bool checkOldPasswordValid(string password, string username)
{
using (DirectoryEntry entry = new DirectoryEntry("WinNT://" + Environment.MachineName + ",computer"))
{
entry.Username = username;
entry.Password = password;
DirectorySearcher searcher = new DirectorySearcher(entry);
searcher.Filter = "(objectclass=user)";
try
{
searcher.FindOne();
}
catch (Exception ex)
{
return false;
}
return true;
}
}
but then directory searcher is not supported with WinNt, so i found another way to loop through all records.
foreach (DirectoryEntry dc in entry.Children)
{
// prints the name
System.Diagnostics.Debug.WriteLine(dc.Name);
}
but this just gets the name and doesnt verify the password.
please help . thanks

To autenticate against LDAP or WinNT, you need no DirectorySearcher. You only need to get the NativeObject from your DirectoryEntry instance. Here's a code sample that might guide you through the way.
public bool Authenticate(string username, string password, string domain) {
bool authenticated = false;
using (DirectoryEntry entry = new DirectoryEntry(#"WinNT://" + domain, username, password) {
try {
object nativeObject = entry.NativeObject;
authenticated = true;
} catch (DirectoryServicesCOMException ex) {
}
}
return authenticated;
}
This code will return either a user is authentic or not. Once you can get the NativeObject property using this DirectoryEntry class instance, this means that the AD (or local computer) used impersonation to get this object. If you get the object without having a thrown exception, this means that the AD (or local computer) was able to authenticate the impersonnated user.
While you can use the currently authenticated user by specifying no username and password, but only the domain (or local computer), by specifying a username and password, you say you want to use impersonnation, so the security infrastructure will use the given username and password to try to retrieve the NativeObject property from this DirectoryEntry class instance.
To authenticate against the AD, just replace the "WinNT://" for "LDAP://".

You can use DirectoryEntry itself.
See the example here: http://support.microsoft.com/kb/316748
Why are you using WinNT:// anyways?

Related

How to validate domain credentials without considering the Cached Domain Credential

I want to know if there's a way to validate domain credential and make sure we don't use the Cached Domain Credential ?
I use this to validate the credential :
bool valid = false;
using (PrincipalContext context = new PrincipalContext(ContextType.Domain))
{
valid = context.ValidateCredentials( username, password );
}
The problem is when I change the password, the old password is still working.
EDIT : If you force the password to be reset, the cached domain credential will not be use. But between the moment we force the reset, and moment the user reset the password, the old password will still work.
Question already has an answer Why does Active Directory validate last password?
Solution is to use a Kerberos authentication.
The following code shows how you can perform credential validation using only Kerberos. The authentication method at use will not fall back to NTLM in the event of failure.
private const int ERROR_LOGON_FAILURE = 0x31;
private bool ValidateCredentials(string username, string password, string domain)
{
NetworkCredential credentials
= new NetworkCredential(username, password, domain);
LdapDirectoryIdentifier id = new LdapDirectoryIdentifier(domain);
using(LdapConnection connection = new LdapConnection(id, credentials, AuthType.Kerberos))
{
connection.SessionOptions.Sealing = true;
connection.SessionOptions.Signing = true;
try
{
connection.Bind();
}
catch (LdapException lEx)
{
if (ERROR_LOGON_FAILURE == lEx.ErrorCode)
{
return false;
}
throw;
}
return true;
}
you might try something like this
try
{
using (var directoryEntry = new DirectoryEntry(ldapPath, userName, password))
{
var invocation = directoryEntry.NativeObject;
return true;
}
}
catch (Exception ex)
{
return false;
}

Login Authentication using Active Directory in the Intranet...Possible?

I am creating this project to be deployed in our company's intranet. I am using this code to authenticate the users login:
entry.Username = strUserName;
entry.Password = strPassword;
DirectorySearcher searcher = new DirectorySearcher(entry);
searcher.Filter = "(objectclass=user)";
try
{
searcher.FindOne();
return true;
}
It working well on my localhost, but when I deployed it the intranet, I can't log in.
Now my question is, can I access the Directory over the intranet? or is there a better way to achieve this?
A simpler method would be to use System.DirectoryServices and System.DirectoryServices.AccountManagement
Use this in a function returning Boolean:
Dim context As PrincipalContext = New PrincipalContext(ContextType.Domain, domainName)
If context.ValidateCredentials(userAlias, userPassword, ContextOptions.Negotiate) Then
Return True
Else
Return False
End If
The snippet is in VB, but you get the idea. Replace domainName with your domain name, userAlias with your username, and userPassword with your password.
This worked great for me in the past:
var ldapConnectionString = "LDAP://servername/CN=Users,DC=domainname,DC=com";
using (var de = new DirectoryEntry(ldapConnectionString, username, password, AuthenticationTypes.Secure))
{
if(de.NativeObject != null)
{
// user is valid ...
}
}
You need a reference to: System.DirectoryServices

Trouble Authenticating ASP.NET Users Against Active Directory

I replaced our domain name with "demo"... please ignore missing commas and such in the image below.
My question is as follows:
I want to authenticate the SBSUsers in my ASP.NET web application. I cannot figure out what my active directory path needs to be in order to get it to work...
When I set it as follows, it fails to authenticate (I assume because my users are not under that path)... but it doesn't give me an error:
string adPath = "LDAP://ac-dc01.demo.local:389/CN=Configuration,DC=demo,DC=local";
string domainAndUsername = domain + #"\" + username;
DirectoryEntry entry = new DirectoryEntry(adPath, domainAndUsername, pwd);
// Bind to the native AdsObject to force authentication.
Object obj = entry.NativeObject;
DirectorySearcher search = new DirectorySearcher(entry);
search.Filter = "(SAMAccountName=" + username + ")";
search.PropertiesToLoad.Add("cn");
SearchResult result = search.FindOne();
if (null == result)
{
return false;
}
// Update the new path to the user in the directory
adPath = result.Path;
_filterAttribute = (String)result.Properties["cn"][0];
When I set it to what I think it should be, it errors on the entry.NativeObject line.
string adPath = "ldap://ac-dc01.demo.local:389/OU=SBSUsers,OU=Users,OU=MyBusiness,DC=demo,DC=local";
Any ideas? Do I need to open it up for "global" access somehow? If so, how would I go about doing that?
I was able to successfully connect using another piece of software...
this is what you can try.. also are you sure that your DC=Demo and DC=Local those look like OU's to me
const string Domain = "ServerAddress:389";
const string constrParts = #"OU=Users,DC=domain,DC=com";
const string Username = #"someusername";
PrincipalContext principalContext = new PrincipalContext(ContextType.Domain, Domain, constrParts);
UserPrincipal userPrincipal = UserPrincipal.FindByIdentity(principalContext, username);
This is how we connect to our AD and it works great:
<yourConfig>LDAP://ADServerName/OU=GROUPNAME,DC=domainName,DC=com</YourConfig>
And here is a sample code on how you can validate a user:
using (PrincipalContext oPrincipalContext = new PrincipalContext(ContextType.Domain,
ENTER YOUR DOMAIN NAME,
This is where the config that I mentioned above comes in,
ContextOptions.Negotiate,
ENTER YOUR AD SERVICE NAME,
ENTER YOUR AD PASSWORD))
{
UserPrincipal oUser = UserPrincipal.FindByIdentity(oPrincipalContext, THE USERNAME THAT YOU WANT TO VALIDATE);
if (oUser != null)
{
oADAcct = new CUserADAcct();
oADAcct.dumpAcctAttrs(oUser);
}
}

Trying to connect using PrincipalContext on Workgroup Server returns Invalid User.

I want to create an Application for editing user accounts on a Server.
The Server do not use AD only local accounts.
I use the following code to connect the remote server:
try
{
PrincipalContext oPrincipalContext = new PrincipalContext(ContextType.Machine, "192.168.123.110", null, ContextOptions.Negotiate, "Administrator", "password");
try
{
MessageBox.Show(oPrincipalContext.ConnectedServer);
GroupPrincipal oGroupPrincipal = GroupPrincipal.FindByIdentity(oPrincipalContext, "Goetter");
try
{
// perform operations here
}
finally
{
oGroupPrincipal.Dispose();
}
}
finally
{
oPrincipalContext.Dispose();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
Whenever I try this, I get an exception, that the user and or password is not authorized, independent of the user I use. Administrator is the build in Admin user account.
Does PrincipalContext only works with AD or also with local accounts? Is anything wrong with my code?
using(PrincipalContext oPrincipalContext = new PrincipalContext(ContextType.Machine, computer.Name, null, ContextOptions.Negotiate, Settings.UserName, Settings.UserPassword))
using(GroupPrincipal oGroupPrincipal = GroupPrincipal.FindByIdentity(oPrincipalContext, Settings.AdministratorsGroup))
{
// perform operations here
}
Change your code and wrap it around a using statement otherwise you may have some errors when trying to call the Dispose() method reason being when you try to dispose the connection may have already been closed by then.
you can use this code here and try either of the examples if you are using ActiveDirectory
example 1
If you work on .NET 3.5, you can use the System.DirectoryServices.AccountManagement namespace and easily verify your credentials:
// create a "principal context" - e.g. your domain (could be machine, too)
using(PrincipalContext pc = new PrincipalContext(ContextType.Domain, "YOURDOMAIN"))
{
// validate the credentials
bool isValid = pc.ValidateCredentials("myuser", "mypassword");
}
Example 2
using System.Security;
using System.DirectoryServices.AccountManagement;
public struct Credentials
{
public string Username;
public string Password;
}
public class Domain_Authentication
{
public Credentials Credentials;
public string Domain;
public Domain_Authentication(string Username, string Password, string SDomain)
{
Credentials.Username = Username;
Credentials.Password = Password;
Domain = SDomain;
}
public bool IsValid()
{
using (PrincipalContext pc = new PrincipalContext(ContextType.Domain, Domain))
{
// validate the credentials
return pc.ValidateCredentials(Credentials.Username, Credentials.Password);
}
}
}
The public bool IsValid() Method above should work for what you are looking for.
Have a look at PrincipalContext.ValidateCredentials
for your FindByIdentity portion you can try the following replacement code
string strName = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
// This is here because of a .Net error that gets 0x80005000 on "isUser = user.IsMemberOf(groupU);"
string domainName = strName.Split('\\')[0];
var pc = new PrincipalContext(ContextType.Domain, domainName);
Additional Reference Link StackOverFlow Post
ContextType.Machine

Active directory - programmatically check supplied credentials

Why does the following code lock the account out after one unsuccessful attempt when the policy in AD is set to three attempts? Is there a better way of checking credentials programmatically against AD.
private bool Authenticate(string userName,
string password, string domain)
{
bool authentic = false;
try
{
DirectoryEntry entry = new DirectoryEntry("LDAP://" + domain,
userName, password);
object nativeObject = entry.NativeObject;
authentic = true;
}
catch (DirectoryServicesCOMException) { }
return authentic;
}
Working fine when the correct credentials are entered...
Thanks,
You might find what you need in this article:
http://www.codeproject.com/Articles/90142/Everything-in-Active-Directory-via-Csharp-NET-3-5-.aspx
specifically the ValidateCredentials method.

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