BFGuard – Day 2

Background

In this post we actually start BFGuard and try to connect to the host from other workstations.

 

Target OS

Here are the Windows OS that we will use for this exercise:

  1. Server
    • Windows Server 2012 R2
  2. Client
    • Windows Server 2012 R2
    • Windows 7

What we saw

BF Guard

BF Guard – Application

Scenario – After 1 failed Login

BF Guard – Application – Statistics

Explanation
  1. ip
    • Count :- 1
    • Date :- 2016-06-15 15:34:13
      • Time in GMT, not local time

 

Scenario – After Numerous failed Logins

BF Guard – Application – Statistics

Explanation
  1. ip
    • Count :- 7
    • Date :- 2016-06-15 16:47:18
      • Time in GMT, not local time

 

BF Guard – Application – Log entrys

Explanation
  1. @ 2017-06-15 09:47:39
    • – Auto blocking IP: for: 54864000 minutes

 

BF Guard – Application – Blocked IP

Explanation
  1. IP Address
    • IP Address :-
    • From :- 2017-06-15 09:47:39
    • To      :- 2017-06-15 10:47:39
    • City    :- Blocked

 

OS – Windows

Windows Logs

Windows Logs – Security

Windows Logs – Security – Filter

Here we filter for “Audit Failure“.

Windows Logs – Security – Logs

And, here are the events captured.

 

Windows Logs – Security – Log – Detailed

Windows Logs – Security – Log – Detailed- Event ID = 4625
Image

 

Explanation
  1. Subject
    • Security SID :- NULL SID
      • Since account that we entered to login in under is not known to the targeted computer or Active Directory, we get “NULL SID
    • Logon ID :-  0x0
      • Again, unknown Logon ID
  2. Logon Type
    • Our Logon Type is 3
      • Logon Type = 3
        • Network
  3. Account for which Logon Failed
    • Security SID :- NULL SID
    • Account Name :- bobsmith
    • Account Domain :- LAB
  4. Failure Information
    • Failure Reason :- unknown username or password
    • Status :- 0xC00006D
    • Sub Status :- 0xC0000064
  5. Process Information
    • Caller Process ID :- 0x0
      • Remote Caller Process is not known
    • Caller Process Name :-
      • Remote Caller Process is not known
  6. Network Information
    • Workstation Name :- ASTSQL01
    • Source Network Address :-
      • Network Address not passed in
    • Source Port :-
      • Network Port not passed in
  7. Detailed Authentication Information
    • Logon Process :- NtlmSsp
    • Authentication Package :- NTLM
  8.  Summary
    • Log Name :- Security
    • Source :- Microsoft Windows security
    • Event ID:- 4625
    • Task Category :- Logon
    • Keywords :- Audit Failure
    • Computer :- Host attempted for logon

 

OS – Windows Firewall

Reviewed server’s Windows Firewall to see how it is configured for “Remote Desktop“.

 

Explanation

  1. Remote Desktop configured as:
    • Domain :- Yes
    • Home/Work :- Yes
    • Public :- No
    • Group Policy – Yes

 

Summary

Unfortunately, Windows was not able to capture the incoming IP Address.

BF Guard was thus unable to read the IP Address from the Windows Logs.

Because of this inability, it is not able to re-configure the local Windows Firewall and have it start blocking the Source IP Address.

 

BFGuard – Day 1

Background

Googled online to identify steps to take for securing MS Windows Terminal Services.

One of the tools mentioned is BFGuard.

BFGuard

What is BFGuard?

BFGuard stands for “Brute Force Guard”.

How does it work?

It principally monitors the local machine’s event log.  The relevant log file in this case is the “Security Log“.

Upon finding entries that indicate failed logins correlative data is gathered.  Obvious correlative data includes username and IP Address.

Once the configured maximum number of failed attempts are reached the specific IP Address is blacklisted.

Download

Please download the free tool from here.

Screen Shots Please

Log Entries

BFGuard_Free_LogEntries_20170615_0629AM

Blocked IP

BFGuard_Free_BlockedIP_20170615_0633PM

WhiteList

BFGuard_Free_WhiteList_20170615_0635AM

Statistics

BFGuard_Free_Statistics_20170615_0638AM

Functionalities

From the screen shots here are the functionalities offered:

  1. A listing of “Blocked IPs
  2. Ability to whitelist specific IP Addresses
  3. Statistics on each connected IP Address

 

Summary

Wanted to introduce the product.

In the days ahead we will revisit and update our post.