Category: Microsoft Security

SPN Scanning – Service Discovery without Network Port Scanning

The best way to discover services in an Active Directory environment is through what I call “SPN Scanning.” The primary benefit of SPN scanning for an attacker over network port scanning is that SPN scanning doesn’t require connections to every IP on the network to check service ports. SPN scanning performs service discovery via LDAP …

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Bypassing EMET 5.2 Security Protection

While EMET 5.2 may only be about a week old, there is already information about one way tor bypassing one of EMET’s security protection methods. r41p41 posted information about ROP bypass in the latest EMET version, 5.2. TLDR: EMET 5.2 can be bypassed with ease by jumping past its hooks using simple ROP 19th March …

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Microsoft EMET 5.2 Now Available!

  Microsoft Security Research and Defense blog posts that Microsoft EMET 5.2 is now available! Following is the list of the main changes and improvements: Control Flow Guard: EMET’s native DLLs have been compiled with Control Flow Guard (CFG). CFG is a new feature introduced in Visual Studio 2015 (and supported by Windows 8.1 and …

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Interesting KRBTGT Password Reset Behavior

Following up on Twitter conversations (@passingthehash, @scriptjunkie1, gentilkiwi, etc) on the new KRBTGT Password Reset Script and Skip Duckwall’s (@passingthehash) blog post on how KRBTGT password changes work. Microsoft KB2549833 states that the KRBTGT password is set automatically to a random string when a new password is entered. This occurs because there is special logic …

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MS15-011 & MS15-014: Microsoft Active Directory Group Policy (GPO) Vulnerabilities Patched

On February’s Patch Tuesday (2/11/2015), Microsoft released two patches that fix issues with the way Group Policy is processed by the client. Interestingly enough, one of these vulnerabilities (MS15-014) makes the other one (MS15-011) not only feasible, but quite capable. The Attack Scenario: An attacker leverages the vulnerability described in MS15-014 to prevent/stop Group Policy …

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Attackers Can Now Use Mimikatz to Implant Skeleton Key on Domain Controllers & BackDoor Your Active Directory Forest

Once an attacker has gained Domain Admin rights to your Active Directory environment, there are several methods for keeping privileged access. Skeleton Key is an ideal persistence method for the modern attacker. More information on Skeleton Key is in my earlier post. Note that the behavior documented in this post was observed in a lab …

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Active Directory Domain Controller Skeleton Key Malware & Mimikatz

Dell SecureWorks posted about the Skeleton Key malware discovered at a customer site. The Skeleton Key malware is installed on one or multiple Domain Controllers running a supported 64bit OS. The malware “patches” the security system enabling a new master password to be accepted for any domain user, including admins. This enables the attacker to …

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PowerShell Security: Execution Policy is Not An Effective Security Strategy – How to Bypass the PowerShell Execution Policy

If you have worked with PowerShell recently, you may have run into an Execution Policy message: c:\temp\Find-PSServiceAccounts.ps1 : File C:\temp\Find-PSServiceAccounts.ps1 cannot be loaded because running scripts is disabled on this system. For more information, see about_Execution_Policies at http://go.microsoft.com/fwlink/?LinkID=135170. At line:1 char:1 + c:\temp\Find-PSServiceAccounts.ps1 + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo          : SecurityError: (:) [], PSSecurityException + FullyQualifiedErrorId : …

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Interesting Windows Computer & Active Directory Well-Known Security Identifiers (SIDs)

The Microsoft Knowledge Base article KB243330 lists the well-known security identifiers in Windows operating systems  Listed here are the more interesting ones from the article as well as some additional ones. Local Computer SIDs SID: S-1-5-2 Name: Network Description: A group that includes all users that have logged on through a network connection. Membership is …

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Detecting MS14-068 Kerberos Exploit Packets on the Wire aka How the PyKEK Exploit Works

MS14-068 References: AD Kerberos Privilege Elevation Vulnerability: The Issue Detailed Explanation of MS14-068 MS14-068 Exploit POC with the Python Kerberos Exploitation Kit (aka PyKEK) Exploiting MS14-068 Vulnerable Domain Controllers Successfully with the Python Kerberos Exploitation Kit (PyKEK) This post shows the packet captures I performed using WireShark on the Domain Controllers during stage 1 and …

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