How-to Investigate Active Directory Logon Mischief

    The Windows domain feature for locking accounts can be a helpful feature against malicious attempts to guess a password via brute force.

    The version of netlogon.dll that has tracing included is installed by default on all currently supported versions of Windows. To enable debug logging, set the debug flag that you want by using nltest.exe, the registry, or Group Policy.

    Group Policy

    You will have to adjust a few policy settings to get the DCs to audit logon events. This are usually set correctly, but it can be worth a check of the environment to make sure the DCs are get the proper audit settings.

    Group Policy

    Audit account logon events for domain accounts and Audit logon events for logons to the computer.

    Events

    The Event IDs we are most concerned with are under the Windows Logs > Security section of Event Viewer.

    • 4624
    • 4776
    Jun 2, 2020 - Filed in: Microsoft Active Directory Windows Server
    Reading Time: 2 minute(s)

    Live Capture to Multiple Files Using Wireshark

    If you want to live capture a long session, maybe over the course of a couple of hours. You will want to perform this so that you can capture the traffic to multiple files, based on size or duration of time, this makes the results much easier for analysts to work with, transferring, etc.

    I like to create a dedicated directory for the capture session. I usually place them in Capture or ProjectNameCapture directorv. Once the capture session is complete, you can select the interesting PCAP files out of the session and delete or archive the others.

    Launch Wireshark application. Open Capture options, select the Output tab.

    Feb 18, 2020 - Filed in: Wireshark
    Reading Time: 2 minute(s)

    OPNsense Security Device Build

    Just back from a security conference. The major themes of the conference were passwords suck, phishing, policies, and solutions. The conference was great, good food and lots of information taken from the talks.

    Scene

    All this security talk got me to thinking about my own setup, a very old Cisco ASA and Cisco Wireless Router pair meets, but doesn’t give much visibility in to the network, and the number of exploits for this hardware / software must be longer than my arm at this point, so time to upgrade.

    Cisco ASA needs to be replaced because it’s software isn’t current, and protecting against newer attacks isn’t possible. Cisco E4200 has to be replaced because it doesn’t support newer Wi-Fi standards.

    Build

    This post and some that follow will be about a security device build I have ongoing. The journey begins at picking a hardware platform, which there are a lot to choose from. I wanted to keep close to router-style as possible, so I opt for a board with no VGA or other display technologies and had a serial port (yes, RS232).

    Bought a bundle that contains board, case, and power adapter. Basically, the only part required is storage, this can be an SD card or USB flash drive. I will be using mSATA drive for log storage (/var). The board I have has three mPCIe slots, but only one will work with mSATA drives, it’s label accordingly.

    APU2D4 (Without SD and SSD)
    Dec 8, 2018 - Filed in: OPNsense
    Reading Time: 5 minute(s)

    Amazon EC2 SSH Public Keys via IAM Service

    There will come a day when we can provision users and provide the necessary authorization to required enterprise resources with easy, but until that day comes there will be hacks like this one.

    This is very much Proof of Concept (PoC), I have not tested this beyond my network, and there would be a lot of angles to consider with any type of deployment, security (sanitization and additional logic), IAM SSH Public Keys were designed for CodeCommit, and other unknowns.

    My first attempt was to create a PAM module that would authenticate SSH users via aws-sdk-cpp libraries, accessing the API using instance profile / EC2 IAM roles, allowing EC2 instances to obtain credentials to access the information. This seemed like a good route, but trying to hack a PAM module together that would be portable enough for distribution would be a challenge, static versions of aws-sdk-cpp, etc. I will revisit this in the future, but for now, I will move on.

    On my second attempt, I create a Bash script that would produce the correct output for SSH AuthorizedKeysCommand directive using SSH public keys from AWS IAM service via awscli. As the EC2 instance can utilize the instance profile role via aws command. This didn’t come without headaches, permission issues, etc.

    Jan 26, 2017 - Filed in: AWS EC2 IAM
    Reading Time: 3 minute(s)