Cyber Threat Intelligence | PacketWatch

Cyber Threat Intelligence Report | 9/21/2026 | PacketWatch

Written by PacketWatch Team Sixty43 | September 21, 2026

 

This week, we briefed our clients on a CISA/NSA document, "Detecting and Mitigating Active Directory Compromises." Be sure to implement these AD controls.


 KEY TAKEAWAYS 

  • Joint publication from CISA/NSA/ASD details most of the known attack techniques for Active Directory, as well as how to detect and mitigate these techniques.

  • Critical and high severity vulnerabilities Microsoft, Cisco, Check Point, and SolarWinds, plus updates to CISA KEV, patch now!


 

Active Directory Attack & Defense

Last week, The Australian Signals Directorate, along with CISA, the NSA, and other international cybersecurity organizations, published a document titled "Detecting and mitigating Active Directory compromises." This document outlines a long list of common and not-so-common attacks on Active Directory (AD), and more importantly, how to detect and mitigate these attacks. It is a rare thing to have this level of detail on so many attacks all documented in one place. This article will highlight some of the attacks mentioned in this document. However, it is strongly encouraged that network security teams and IT administrators review this document thoroughly and implement as many of the recommended controls as possible. While every environment is unique, and not every control can be implemented universally, taking these proactive measures will ensure that threat actors have a much harder time achieving their goals, giving security teams extra time to detect and prevent further intrusions.  

 

The "Why" of AD Security

The document provides such a great summary of why AD security is so important, it is best to quote it in its entirety: "The immediate objective of malicious activity involving Active Directory is to escalate privileges and gain control of a domain by targeting the highest privileged user objects, such as those in the Domain Admins and Enterprise Admins security groups. Although significant access can often be obtained by targeting other user objects, such as service accounts, preventing malicious actors from acquiring the highest privileges is crucial for limiting their overall access. Therefore, securing privileged access is essential for mitigating Active Directory compromises and should be a top priority for all organizations."

Securing AD means making it as difficult as possible for threat actors to elevate privileges and gain control of the domain.

 

The AD Attack Methods

The following is a list of all of the attack methods that are discussed in detail in the document. While some of these are more common than others, they all represent different methods and techniques threat actors can employ to escalate privileges and gain control of a domain. Steps should be taken to ensure these are prevented or made as difficult as possible.

  • Kerberoasting
  • Authentication Server Response (AS-REP) Roasting
  • Password Spraying
  • MachineAccountQuota compromise
  • Unconstrained Delegation
  • Password in Group Policy Preferences (GPP) compromise
  • Active Directory Certificate Services (AD CS) compromise
  • Golden Certificate
  • DCSync
  • Dumping ntds.dit
  • Golden Ticket
  • Silver Ticket
  • Golden Security Assertion Markup Language (SAML)
  • Microsoft Entra Connect Compromise
  • One-way domain trust bypass
  • Security Identifier (SID) History compromise
  • Skeleton Key
  • Shadow Credentials

 

Kerberoasting

This technique is one of the more widely known and popular techniques among threat actors. When a user object is configured with a service principal name (SPN), also known as service accounts, any other user object can request its ticket granting service (TGS) from a Domain Controller. This TGS ticket is encrypted with the user object's password hash. Once the threat actor has this, they can take the hash offline and crack it, which in turn can reveal the plaintext password of that service account. If the service account in question has administrative privileges, the threat actor now has access to a privileged account and can pivot deeper into the network. Many common "red team" tools help automate the Kerberoasting process, such as Mimikatz, Rubeus, and Impacket.

Since this functionality is a built-in feature of Windows, Kerberoasting cannot be blocked outright. However, several steps can be taken to make it a non-viable option for the attacker:

  • Minimize the number of user objects configured with SPNs. Remove service accounts that are unnecessary and give the remaining accounts the least amount of privileges necessary to perform their function. This greatly reduces the potential attack surface.
  • Create user objects with SPNs as group Managed Service Accounts (gMSAs). These types of account objects have automatic password rotation, a 120-character password, and simplified SPN management. The extra-long password makes cracking them far less likely.
  • Enable Advanced Encryption Standard (AES) encryption for user objects configured with SPNs. Active Directory uses RC4 encryption as the default for TGS tickets. Using AES encryption instead drastically increases the compute overhead required to crack the password.

 

Password Spraying

Password spraying is when a threat actor attempts to authenticate to multiple user objects using a single password, or a small set of passwords. These passwords are typically found in wordlists or 3rd party data breaches, where common/weak passwords are frequently observed. By "spraying" these weak passwords across many or all user accounts, the threat actor hopes that at least one user is using the same weak password. Even in 2026, weak passwords are still extremely common, and users tend to reuse passwords across multiple accounts, making this technique extremely effective. It is also more difficult to detect as it does not trigger account lockouts for failed password attempts.

  • For local administrator accounts, service accounts, and break glass accounts, use passwords with a minimum of 30 characters. Ensure these passwords are unique, unpredictable, and managed.
  • For regular user accounts, ensure passwords are at least 15 characters in length.
  • Lock out user objects (except for break glass accounts) after five failed logon attempts.
  • Scan the network on a regular (ideally monthly) basis to identify any credentials that are being stored in the clear. Threat actors will often do this themselves when they gain an initial foothold on the network. If they can simply find admin credentials in plaintext, there is no need for them to waste time with any of these other methods.

 

Dumping ntds.dit

The ntds.dit file is the New Technology Directory Services Directory Information Tree, and is the AD Domain Services database that stores information about all objects in the domain, including password hashes for user and computer objects. A copy of this file is stored on every domain controller (except read-only Domain Controllers), and is frequently targeted by threat actors. Any user object that can log on to Domain Controllers, such as members of the Domain Admins security group, can access the ntds.dit file. Since some of the information in the ntds.dit file is encrypted, threat actors will also need to retrieve the SYSTEM hive from the registry of the same Domain Controller that they obtained the ntds.dit file. If the threat actor successfully obtains the ntds.dit file and the SYSTEM hive, they can decrypt the ntds.dit file and then attempt to crack every password hash for every user and computer object in the domain.

  • Ensure Domain Controllers have fully up-to-date EDR deployed. Modern EDR tools can catch/prevent dumping of the ntds.dit file.
  • Limit access to Domain Controllers to only privileged users that require access.
  • Restrict privileged access pathways to Domain Controllers to jump servers and secure admin workstations (network segmentation).
  • Do not install any non-security-related services or applications on Domain Controllers.
  • Centrally log and analyze Domain Controller logs.
  • Disable the Print Spooler service on Domain Controllers. This service is frequently targeted by threat actors to gain access to the DC.
  • Disable Server Message Block (SMB) version 1 on Domain Controllers. This version of SMB is extremely vulnerable and has many attacks and tools that allow threat actors to exploit it to gain access to the server.

 

Conclusion

These summaries only scratch the surface of the wealth of information in this document. As mentioned above, it is highly recommended that security teams and network administrators review the document and implement the hardening and detection recommendations. Hardening Active Directory is one of the best things organizations can do to protect their network from modern threat actors. 

 

Resources:

 

 

Vulnerability Roundup

 

Record-Breaking Patch Tuesday 

Yet another Patch Tuesday vulnerability record was broken this month, with Microsoft addressing 975 new vulnerabilities. This massive increase in vulnerability findings is due to the use of AI tools to audit their source code. The security updates for September include fixes for two vulnerabilities that are under active exploitation, CVE-2026-85880 and CVE-2026-81963 (see the CISA KEV list below for more details). Regular patching of Windows systems is always important, but with the ever-increasing volume of vulnerabilities that are disclosed and fixed each month, it is important that administrators stay up-to-date on Windows patch cycles.

 

Max-Severity Flaw in Cisco ISE

Cisco has disclosed a maximum-severity vulnerability in their Identity Services Engine (ISE) that is under active exploitation. Tracked as CVE-2026-76460, the vulnerability allows an unauthenticated remote attacker to bypass authentication. It affects Cisco ISA and Cisco ISE Passive Identity Connector (ISE-PIC), regardless of device configuration. The table below shows the fixed release versions:

 

Fig. 1: Cisco ISE Fixed Release Versions | Source: Cisco

 

Administrators are urged to patch as soon as possible as this vulnerability is under active exploitation. Cisco also strongly urges administrators to review the access.log file on ISE servers to look for suspicious usernames. Details of how to review this file can be found in the Cisco advisory here.

 

Critical Vulnerability in Cisco Secure FMC

Cisco recently disclosed a critical vulnerability in their Secure Firewall Management Center. Tracked as CVE-2026-20324, successful exploitation can allow for a remote authenticated attacker to execute arbitrary commands as root. This vulnerability affects all Cisco Secure FMC Software if sftunnel is enabled (this feature is enabled by default). For further information on the sftunnel protocol from Cisco, read the documentation here. Administrators are urged to apply the patch as soon as possible.



Multiple Critical Vulnerabilities in Check Point Servers

On September 9, Check Point addressed two critical vulnerabilities in their VPN products. The first, CVE-2026-85102, is an authentication bypass and remote code execution (RCE) flaw in Remote Access and Site-to-Site VPN. The second, CVE-2026-85103, is a buffer overflow flaw during the ASN.1 decoding of a VPN certificate that can lead to RCE. Both vulnerabilities affect the same versions:

  • R82.10 with Jumbo Hotfix Take 43 or below
  • R82 with Jumbo Hotfix Take 125 or below
  • R81.20 with Jumbo Hotfix Take 165 or below

A week later, Check Point disclosed a critical vulnerability in their Security Management and Log Servers. Tracked as CVE-2026-91843, this stack-based buffer overflow flaw in the login process for these server instances allow an unauthenticated remote attacker to execute arbitrary code with root privileges. This vulnerability affects the following versions:

  • R82.20
  • R82.10 Jumbo Hotfix Take 44 or lower
  • R82 Jumbo Hotfix Take 126 or lower
  • R81.20 Jumbo Hotfix Take 166 or lower
  • R81.10 Jumbo Hotfix Take 190 or lower (EoS)
  • R80, R80.10, R80.20, R80.30, R80.40, R81 (all EoS)

Administrators are urged to patch as soon as possible.

 

Unauthenticated RCE in SolarWinds ARM

SolarWinds released a patch for CVE-2026-28326, an unauthenticated remote code execution (RCE) vulnerability due to a hardcoded static key in SolarWinds Access Rights Manager. The flaw affects SolarWinds ARM 2026.2 and all previous versions. Administrators are urged to patch as soon as possible.




CISA KEV Additions

The following vulnerabilities were added to CISA's Known Exploited Vulnerabilities Catalog in the last 2 weeks:

  • CVE-2025-39682 - Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability
  • CVE-2026-53266 - Linux Kernel Out-of-Bounds Write Vulnerability
  • CVE-2025-39964 - Linux Kernel Race Condition Vulnerability
  • CVE-2026-87886 - Acronis Backup Incorrect Default Permissions Vulnerability
  • CVE-2026-76460 - Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability
  • CVE-2026-58704 - Google Pixel Improper Authorization Vulnerability
  • CVE-2026-76461 - Cisco Secure Email Gateway SQL Injection Vulnerability
  • CVE-2026-86706 - GitLab Community Edition and Enterprise Edition Path Traversal Vulnerability
  • CVE-2026-42018 - JFrog Artifactory Improper Authentication Vulnerability
  • CVE-2026-42016 - JFrog Artifactory Incorrect Authorization Vulnerability
  • CVE-2026-84869 - ConnectWise ScreenConnect Improper Privilege Management and Missing Authorization Vulnerability
  • CVE-2026-67277 - MikroTik RouterOS Missing Authentication for Critical Function Vulnerability
  • CVE-2026-86060 - MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability
  • CVE-2026-20079 - Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability
  • CVE-2026-87491 - Google Chromium V8 Out of Bounds Write Vulnerability
  • CVE-2025-25249 - Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
  • CVE-2026-19490 - Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
  • CVE-2026-85880 - Microsoft Windows Heap-Based Buffer Overflow Vulnerability
  • CVE-2026-86218 - N-able N-central Static Code Injection Vulnerability
  • CVE-2026-81963 - Microsoft Windows Link Following Vulnerability
  • CVE-2026-75650 - Adobe Commerce and Magento Improper Neutralization of Special Elements Used in a Template Engine Vulnerability

 

 

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