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How to authenticate in LDAP in C#?

I am new to LDAP related coding and today I am asked to develop a code to check the users authentication against LDAP.
The tutorials I have found online are so simple but our company's Directory is so complicated that I don't know how to write a code for that. Here is the info of the LDAP . I have changed the company name to hide the name.
string domain = "ou=People,dc=my,dc=com";
string LDAP_Path= "dc01.my.com;
string LDAPconnect= "LDAP://dc01.my.com/";
Here is a code I have developed but it gives me error when run " LdapResult = LdapSearcher.FindOne();":
string domain = "ou=People,dc=my,dc=com";
string password = "";
string userName = "";
// define your connection
LdapConnection ldapConnection = new LdapConnection(LDAP_Path);
try
{
// authenticate the username and password
using (ldapConnection)
{
// pass in the network creds, and the domain.
var networkCredential = new NetworkCredential(userName, password, domain);
// if we're using unsecured port 389, set to false. If using port 636, set this to true.
ldapConnection.SessionOptions.SecureSocketLayer = false;
// since this is an internal application, just accept the certificate either way
ldapConnection.SessionOptions.VerifyServerCertificate += delegate { return true; };
// to force NTLM\Kerberos use AuthType.Negotiate, for non-TLS and unsecured, just use AuthType.Basic
ldapConnection.AuthType = AuthType.Basic;
// authenticate the user
ldapConnection.Bind(networkCredential);
Response.Write( "connect ldap success");
}
}
catch (LdapException ldapException)
{
Response.Write(ldapException + " <p>Ad connect failed</p>");
//Authentication failed, exception will dictate why
}
string strTmp0 = LDAPconnect + domain;
string user = "memberId";
string pwd = "memberPwd";
System.DirectoryServices.DirectoryEntry LdapEntry = new System.DirectoryServices.DirectoryEntry(strTmp0, "cn=" + user, pwd, AuthenticationTypes.None);
DirectorySearcher LdapSearcher = new DirectorySearcher(LdapEntry);
LdapSearcher.Filter = "(cn=" + user + ")";
string value = string.Empty;
SearchResult LdapResult=null;
try
{
LdapResult = LdapSearcher.FindOne();
}
catch (Exception ex)
{
Response.Write(ex.Message.ToString());
// .............get Error msg : username an password uncorrect
}
if ((LdapResult != null))
{
Response.Write("ldapresult not null");
}
Could anybody help plz?

In ldap connection setting , OP should use own configuration.
// Ldap connection setting. this should setup according to organization ldap configuration
int portnumber = 12345;
LdapConnection ldapConnection = new LdapConnection(new LdapDirectoryIdentifier("ldap.testxxxx.com", portnumber));
ldapConnection.AuthType = AuthType.Anonymous;
ldapConnection.Bind();
SearchRequest Srchrequest = null;
SearchResponse SrchResponse = null;
SearchResultEntryCollection SearchCollection = null;
Hashtable UserDetails = new Hashtable();
Srchrequest = new SearchRequest("distniguishged name e.g. o=testxxx.com", string.Format(CultureInfo.InvariantCulture, "preferredmail=test#testxxxx.com"), System.DirectoryServices.Protocols.SearchScope.Subtree);
SrchResponse = (SearchResponse)ldapConnection.SendRequest(Srchrequest);
SearchCollection = SrchResponse.Entries;
foreach (SearchResultEntry entry in SearchCollection)
{
foreach (DictionaryEntry att in entry.Attributes)
{
if (((DirectoryAttribute)(att.Value)).Count > 0)
{
UserDetails.Add(att.Key.ToString(), ((DirectoryAttribute)(att.Value))[0].ToString());
}
else
{
UserDetails.Add(att.Key.ToString(), string.Empty);
}
}
}
if (UserDetails.Count > 1)
{
Console.WriteLine("User exists");
}
else
{
Console.WriteLine("User does not exist");
}

You can use the DirectoryInfo conrstructor that has user and password arguments. That way, you don't need to do a query to the LDAP, you can simplify your code.
string username = "frederic";
string password = "myFanciPassword99";
string domain = "ou=People,dc=my,dc=com";
string LDAPconnect= "LDAP://dc01.my.com/";
string connectionString = LDAPconnect + domain;
bool userValid = false;
// Note: DirectoryEntry(domain, username, password) would also work
DirectoryEntry entry = new DirectoryEntry(connectionString, username, password);
try
{
// Bind to the native AdsObject to force authentication.
Object obj = entry.NativeObject;
userValid = true;
}
catch (Exception ex)
{
}

How to authenticate users in C# LDAP

I am new to LDAP related coding and today I am asked to develop a code to check the users authentication against LDAP.
The tutorials I have found online are so simple but our company's Directory is so complicated that I don't know how to write a code for that. Here is the info of the LDAP . I have changed the company name to hide the name.
uri = ldaps://ABC.ad.XYZ.com:636
user_filter = memberOf=CN=TENXAIRFLOWPROD,OU=Security Groups,OU=Normal Users and Groups,OU=Account Management Services,OU=AD Master OU,DC=ABC,DC=ad,DC=XYZ,DC=com
user_name_attr = sAMAccountName
superuser_filter = memberOf=CN=TENXAIRFLOWPROD_ADM,OU=Security Groups,OU=Normal Users and Groups,OU=Account Management Services,OU=AD Master OU,DC=ABC,DC=ad,DC=XYZ,DC=com
bind_user = SCGLOBAL\twiki
bind_password_cmd = python /bns/tenx/airflow/ldap_password.py
basedn = DC=ABC,DC=ad,DC=XYZ,DC=com
search_scope = SUBTREE
Here is a code I have developed but it gives me error:
string username = "myUserName";
string domain = "ldaps://ABC.ad.XYZ.com:636";
string pwd = "myPasword";
try
{
DirectoryEntry entry = new DirectoryEntry(domain, username, pwd);
//Bind to the native AdsObject to force authentication.
object obj = entry.NativeObject;
lblError.Text=("Login Successful");
//search some info of this user if any
DirectorySearcher search = new DirectorySearcher(entry);
search.Filter = "(SAMAccountName=" + username + ")";
SearchResult result = search.FindOne();
}
catch (Exception ex)
{
lblError.Text=("Login failed: " + ex.ToString());
}
Could anybody help plz?

Comment: According to the admin , I have been assigned to the group in AD. But how can I make sure I can access it?
It seems like Active Directory. If so, you could just use PrincipalContext.
public bool ValidateCredentials(string domain, string username, string password)
{
using (var context = new PrincipalContext(ContextType.Domain, domain))
{
return context.ValidateCredentials(username, password);
}
}
public bool IsUserInAdGroup(string domain, string username, string adGroupName)
{
bool result = false;
using (var context = new PrincipalContext(ContextType.Domain, domain))
{
var user = UserPrincipal.FindByIdentity(context, username);
if (user != null)
{
var group = GroupPrincipal.FindByIdentity(context, adGroupName);
if (group != null && user.IsMemberOf(group))
result = true;
}
}
return result;
}
Please make sure to reference System.DirectoryServices.AccountManagement.

LDAP authentication on server

I need to authenticate LDAP user in c# with input username and password.
DirectoryEntry entry =
new DirectoryEntry("LDAP://" + ServerName + "/OU=managed users,OU=KK”, + LDAPDomain, AdminUsername, Adminpassword);
DirectorySearcher search = new DirectorySearcher(entry);
search.SearchScope = SearchScope.Subtree;
search.Filter = "(|(&(objectCategory=person)(objectClass=user)(name=" + inputUsername + ")))";
search.PropertiesToLoad.Add("cn");
var searchresult = search.FindAll();
And here I get the required record (could see the details)
However when I try to authenticate it using below code, it always said authentication failure
if (searchresult != null)
{
foreach (SearchResult sr in searchresult)
{
DirectoryEntry myuser = sr.GetDirectoryEntry();
myuser.Password = inputPassword;
try
{
object nativeObject = myuser.NativeObject;
if (nativeObject != null)
isValid = true;
}
catch(excecption ex)
{
isValid = false;
//Error message
}
}
}
It always result in catch block with error message
Logon failure: unknown user name or bad password. failure: unknown user name or bad password.
I'm sure that the given password is correct.
Please suggest.
As suggest by Saad,
I changed by code
public static bool IsAuthenticated()
{
var isValid = false;
string adServer = ConfigurationManager.AppSettings["Server"];
string adDomain = ConfigurationManager.AppSettings["Domain"];
string adminUsername = ConfigurationManager.AppSettings["AdminUsername"];
string adminpassword = ConfigurationManager.AppSettings["Password"];
string username = ConfigurationManager.AppSettings["Username"];
string selection = ConfigurationManager.AppSettings["Selection"];
string[] dc = adDomain.Split('.');
string dcAdDomain = string.Empty;
foreach (string item in dc)
{
if (dc[dc.Length - 1].Equals(item))
dcAdDomain = dcAdDomain + "DC=" + item;
else
dcAdDomain = dcAdDomain + "DC=" + item + ",";
}
string domainAndUsername = dcAdDomain + #"\" + adminUsername;
DirectoryEntry entry = new DirectoryEntry("LDAP://" + adServer, domainAndUsername, adminpassword);
try
{
//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();
Console.WriteLine("And here is the result = " + result);
if (null == result)
{
isValid = false;
}
//Update the new path to the user in the directory.
var _path1 = result.Path;
var _filterAttribute = (string)result.Properties["cn"][0];
Console.WriteLine("And here is the _path1 = " + _path1);
Console.WriteLine("And here is the _filterAttribute = " + _filterAttribute);
isValid = true;
}
catch (Exception ex1)
{// your catch here
Console.WriteLine("Exception occurred " + ex1.Message + ex1.StackTrace);
}
return isValid;
}
Still it is giving error
Exception occurred Logon failure: unknown user name or bad passwor
d.
at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
at System.DirectoryServices.DirectoryEntry.Bind()
at System.DirectoryServices.DirectoryEntry.get_NativeObject()
at Portal.LdapTest.Program.IsAuthenticated()
I think I am confused with which parameter to give where.
I have
LDAP server address something like 123.123.12.123
Domain Name like abc.com
Admin username and password and
Username and password which is needs be authenticated. (which is in OU=new users,OU=KK )
I am creating directory entry using servername, domain, admin username and password
How do I validate the username with given password?

This code works for me,try it and let me know (modify the filters and properties to suit your needs):
public bool IsAuthenticated(string domain, string username, string pwd){
string domainAndUsername = domain + #"\" + username;
DirectoryEntry entry = new DirectoryEntry(_path, domainAndUsername, pwd);
try
{
//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.
_path = result.Path;
_filterAttribute = (string)result.Properties["cn"][0];
}
catch(Exception e){// your catch here
}
}

public bool AuthenticateUser(string EmailAddress, string password,out string msg)
{
msg = string.Empty;
if (password == null || password == string.Empty || EmailAddress == null || EmailAddress == string.Empty)
{
msg = "Email and/or password can't be empty!";
return false;
}
try
{
ADUserInfo userInfo = GetUserAttributes(EmailAddress);
if (userInfo == null)
{
msg = "Error: Couldn't fetch user information!";
return false;
}
DirectoryEntry directoryEntry = new DirectoryEntry(LocalGCUri, userInfo.Upn, password);
directoryEntry.AuthenticationType = AuthenticationTypes.None;
string localFilter = string.Format(ADSearchFilter, EmailAddress);
DirectorySearcher localSearcher = new DirectorySearcher(directoryEntry);
localSearcher.PropertiesToLoad.Add("mail");
localSearcher.Filter = localFilter;
SearchResult result = localSearcher.FindOne();
if (result != null)
{
msg = "You have logged in successfully!";
return true;
}
else
{
msg = "Login failed, please try again.";
return false;
}
}catch (Exception ex)
{
//System.ArgumentException argEx = new System.ArgumentException("Logon failure: unknown user name or bad password");
//throw argEx;
msg = "Wrong Email and/or Password!";
return false;
}
}

How to authenticate in LDAP?

I am trying to make a simple authentication system with LDAP in .NET.
I was checking some namespaces in .NET and simply make the standart code snippet as below.
DirectoryEntry de = new DirectoryEntry(path,username,password);
DirectorySearcher s = new DirectorySearcher(de);
s.Filter = "(&(cn=" + username2 + "))";
SearchResult result = s.FindOne();
if (result != null) {
Console.WriteLine("User exists");
} else {
Console.WriteLine("User does not exist");
}
I have an admin username and password, username and password, which I use to authenticate the client application. I have a second username and password, username2 and password2 that needs to be checked in the LDAP to log in.
username is the admin account and username2 is just an user in LDAP. So how can I check username2's password?

A slightly backwards (and clunky) way is to log in as the user and try to retrieve something, then treat an exception as an invalid password:
static bool CheckUser(string userName, string password)
{
var adSettings = ConfigurationManager.ConnectionStrings["ActiveDirectory"];
if (adSettings == null ||
string.IsNullOrWhiteSpace(adSettings.ConnectionString))
{
return false;
}
try
{
using (var de = new DirectoryEntry(adSettings.ConnectionString, userName, password))
{
// This should throw an exception if the password is wrong
object nativeObject = de.NativeObject;
}
}
catch (DirectoryServicesCOMException)
{
// Wrong password
return false;
}
catch (System.Runtime.InteropServices.COMException)
{
// Can't connect
return false;
}
return true;
}

I have something in VB which might help you out i guess. Was working on this few days ago with my collegue. Do let me know---
Code:
Dim cookie As HttpCookie = New HttpCookie("username")
cookie.Value = TextBox1.Text
cookie.Expires = DateAndTime.Now.AddHours(12)
Response.Cookies.Add(cookie)
Dim entry As New DirectoryEntry("LDAP://xyz.com/dc=xyz,dc=com", TextBox1.Text, TextBox2.Text)
Try
Dim obj As New Object
obj = entry.NativeObject
Dim search As New DirectorySearcher(entry)
search.Filter = "(SAMAccountName=" + TextBox1.Text + ")"
search.PropertiesToLoad.Add("cn")
Dim result As SearchResult
result = search.FindOne()
If result.Equals(Nothing) then
MsgBox("Try Again with valid username")
Else
MsgBox("User Found!")
Response.Redirect("~/Dashboard.aspx")
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub

LDAP SetPassword Access is Denied

the following code was working for 3 months without any problems.
Since today I am getting the following error;
“Exception has been thrown by the target of an invocation”
and the inner exception;
"Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)"
The authentication function works. Here are my functions;
public bool Authenticate(string strUserName, string strPassword)
{
bool authenticated = false;
using (
var entry = new DirectoryEntry("LDAP://myldapserver", strUserName + "#domain", strPassword,
AuthenticationTypes.Secure))
{
try
{
object nativeObject = entry.NativeObject;
authenticated = true;
}
catch (DirectoryServicesCOMException ex)
{
return false;
}
}
return authenticated;
}
And the ChangePassword Method;
public bool ChangePassword(string strUserName, string strOldPassword, string strNewPassword)
{
const long ADS_OPTION_PASSWORD_PORTNUMBER = 6;
const long ADS_OPTION_PASSWORD_METHOD = 7;
const int ADS_PASSWORD_ENCODE_REQUIRE_SSL = 0;
const int ADS_PASSWORD_ENCODE_CLEAR = 1;
string strPort = "636";
int intPort;
intPort = Int32.Parse(strPort);
try
{
string strUserString = "domain" + #"\" + strUserName.Trim();
var entry = new DirectoryEntry("LDAP://myldapserver", strUserString, strOldPassword,
AuthenticationTypes.Secure);
var search = new DirectorySearcher(entry);
string strFilter = "(SAMAccountName=" + strUserName + ")";
search.Filter = strFilter;
SearchResult result = search.FindOne();
DirectoryEntry user = result.GetDirectoryEntry();
user.Invoke("SetOption", new object[] { ADS_OPTION_PASSWORD_PORTNUMBER, intPort });
user.Invoke("SetOption", new object[] { ADS_OPTION_PASSWORD_METHOD, ADS_PASSWORD_ENCODE_CLEAR });
**user.Invoke("SetPassword", new object[] { strNewPassword });**
user.CommitChanges();
user.Close();
}
catch (Exception exception)
{
string msg = exception.InnerException.Message;
return false;
}
return true;
}
It throws the expcetion when I invoke the SetPassword property.
Any help would be greatly appreciated.

Here is the example:-
PrincipalContext pr = new PrincipalContext(ContextType.Domain, "corp.local", "OU=" + OU + ",OU=Users,dc=corp,dc=local", username, password);
UserPrincipal us = new UserPrincipal(pr);
To Change the Password
user.SetPassword("setPassword");
If you want the user should change the password at next Logon, you can use like this.
user.ExpirePasswordNow();
Here is your full code:-
public static Boolean ResetPassword(string username, string password, string DomainId, string setpassword, Boolean UnlockAccount,Boolean NextLogon)
{
PrincipalContext pr = new PrincipalContext(ContextType.Domain, "corp.local", "dc=corp,dc=local", username, password);
UserPrincipal user = UserPrincipal.FindByIdentity(pr, DomainId);
Boolean flag = false;
if (user != null && user.Enabled == true)
{
if (UnlockAccount)
{
user.UnlockAccount();
}
user.SetPassword(setpassword);
if (NextLogon)
{
user.ExpirePasswordNow();
}
user.Save();
flag = true;
}
else
{
flag = false;
}
user.Dispose();
pr.Dispose();
return flag;
}
I found a good article here, if you want to use it in your way, have a look here,
http://www.primaryobjects.com/cms/article66.aspx