Windows Multiple Invalid Users Fail To Authenticate Using Kerberos: endpointEndpointNoneversion:12
The following analytic identifies a source endpoint failing to authenticate with 30 unique invalid domain users using the Kerberos protocol. This detection leverages EventCode 4768, specifically looking for failure code 0x6, indicating the user is not found in the Kerberos database. This activity is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges. If confirmed malicious, this could lead to unauthorized access or privilege escalation within the Active Directory environment, posing a significant security risk.
Kerberos Pre-Authentication Flag Disabled in UserAccountControl: endpointEndpointNoneversion:12
The following analytic detects when the Kerberos Pre-Authentication flag is disabled in a user account, using Windows Security Event 4738. This event indicates a change in the UserAccountControl property of a domain user object. Disabling this flag allows adversaries to perform offline brute force attacks on the user's password using the AS-REP Roasting technique. This activity is significant as it can be used by attackers with existing privileges to escalate their access or maintain persistence. If confirmed malicious, this could lead to unauthorized access and potential compromise of sensitive information.
Windows Domain Admin Impersonation Indicator: endpointEndpointNoneversion:13
The following analytic identifies potential Kerberos ticket forging attacks, specifically the Diamond Ticket attack. This is detected when a user logs into a host and the GroupMembership field in event 4627 indicates a privileged group (e.g., Domain Admins), but the user does not actually belong to that group in the directory service. The detection leverages Windows Security Event Log 4627, which logs account logon events. The analytic cross-references the GroupMembership field from the event against a pre-populated lookup of actual group memberships. Its crucial to note that the accuracy and effectiveness of this detection heavily rely on the users diligence in populating and regularly updating this lookup table. Any discrepancies between the events GroupMembership and the lookup indicate potential ticket forging. Kerberos ticket forging, especially the Diamond Ticket attack, allows attackers to impersonate any user and potentially gain unauthorized access to resources. By forging a ticket that indicates membership in a privileged group, an attacker can bypass security controls and gain elevated privileges. Detecting such discrepancies in group memberships during logon events can be a strong indicator of this attack in progress, making it crucial for security teams to monitor and investigate. If validated as a true positive, this indicates that an attacker has successfully forged a Kerberos ticket and may have gained unauthorized access to critical resources, potentially with elevated privileges.
Disabled Kerberos Pre-Authentication Discovery With Get-ADUser: endpointEndpointNoneversion:15
The following analytic detects the execution of the `Get-ADUser` PowerShell cmdlet with parameters indicating a search for domain accounts with Kerberos Pre-Authentication disabled. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific activity. This behavior is significant because discovering accounts with Kerberos Pre-Authentication disabled can allow adversaries to perform offline password cracking. If confirmed malicious, this activity could lead to unauthorized access to user accounts, potentially compromising sensitive information and escalating privileges within the network.
ServicePrincipalNames Discovery with PowerShell: endpointEndpointNoneversion:13
The following analytic detects the use of `powershell.exe` to query the domain for Service Principal Names (SPNs) using Script Block Logging EventCode 4104. It identifies the use of the KerberosRequestorSecurityToken class within the script block, which is equivalent to using setspn.exe. This activity is significant as it often precedes kerberoasting or silver ticket attacks, which can lead to credential theft. If confirmed malicious, attackers could leverage this information to escalate privileges or persist within the environment.
Mimikatz PassTheTicket CommandLine Parameters: endpointEndpointNoneversion:13
The following analytic detects the use of Mimikatz command line parameters associated with pass-the-ticket attacks. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns related to Kerberos ticket manipulation. This activity is significant because pass-the-ticket attacks allow adversaries to move laterally within an environment using stolen Kerberos tickets, bypassing normal access controls. If confirmed malicious, this could enable attackers to escalate privileges, access sensitive information, and maintain persistence within the network.
Kerberos TGT Request Using RC4 Encryption: endpointEndpointNoneversion:12
The following analytic detects a Kerberos Ticket Granting Ticket (TGT) request using RC4-HMAC encryption (type 0x17) by leveraging Event 4768. This encryption type is outdated and its presence may indicate an OverPass The Hash attack. Monitoring this activity is crucial as it can signify credential theft, allowing adversaries to authenticate to the Kerberos Distribution Center (KDC) using a stolen NTLM hash. If confirmed malicious, this could enable unauthorized access to systems and resources, potentially leading to lateral movement and further compromise within the network.
Windows Multiple Users Failed To Authenticate Using Kerberos: endpointEndpointNoneversion:12
The following analytic identifies a single source endpoint failing to authenticate with 30 unique users using the Kerberos protocol. It leverages EventCode 4771 with Status 0x18, indicating wrong password attempts, and aggregates these events over a 5-minute window. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges in an Active Directory environment. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, and potential compromise of sensitive information.
Kerberos Pre-Authentication Flag Disabled with PowerShell: endpointEndpointNoneversion:13
The following analytic detects the use of the `Set-ADAccountControl` PowerShell cmdlet with parameters that disable Kerberos Pre-Authentication. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific command execution. Disabling Kerberos Pre-Authentication is significant because it allows adversaries to perform offline brute force attacks against user passwords using the AS-REP Roasting technique. If confirmed malicious, this activity could enable attackers to escalate privileges or maintain persistence within an Active Directory environment, posing a severe security risk.
Kerberoasting spn request with RC4 encryption: endpointEndpointNoneversion:15
The following analytic detects potential Kerberoasting attacks by identifying Kerberos service ticket requests with RC4 encryption through Event ID 4769. It leverages specific Ticket_Options values commonly used by Kerberoasting tools. This activity is significant as Kerberoasting allows attackers to request service tickets for domain accounts, typically service accounts, and crack them offline to gain privileged access. If confirmed malicious, this could lead to unauthorized access, privilege escalation, and further compromise of the Active Directory environment.
Rubeus Kerberos Ticket Exports Through Winlogon Access: endpointEndpointNoneversion:15
The following analytic detects an uncommon process requesting full access rights to winlogon.exe, which may indicate Rubeus exporting Kerberos tickets from memory.
It leverages Sysmon EventCode 10 and checks for full-access rights, specifically the value 0x1f3fff.
Kerberos Service Ticket Request Using RC4 Encryption: endpointEndpointNoneversion:13
The following analytic detects Kerberos service ticket requests using RC4 encryption, leveraging Kerberos Event 4769. This method identifies potential Golden Ticket attacks, where adversaries forge Kerberos Granting Tickets (TGT) using the Krbtgt account NTLM password hash to gain unrestricted access to an Active Directory environment. Monitoring for RC4 encryption usage is significant as it is rare in modern networks, indicating possible malicious activity. If confirmed malicious, attackers could move laterally and execute code on remote systems, compromising the entire network. Note: This detection may be bypassed if attackers use the AES key instead of the NTLM hash.
Windows AD User Suspicious UPN Change: endpointEndpointNoneversion:1
The following analytic detects a user account modifying its own userPrincipalName (UPN) to match the sAMAccountName of another account via Windows Security Event 4738.
This is the setup step of the ResetNightmare attack (CVE-2026-27912), where an attacker with WriteProperty rights on their own UPN attribute spoofs their identity to a target account.
The KDC then resolves a ptype=10 (NT-ENTERPRISE) Kerberos pre-authentication request against the spoofed UPN, issuing a kadmin/changepw TGT that can be used to change the target account's password via kpasswd (port 464).
Event 4738 is generated when a user account attribute is changed. This analytic filters to events where the SubjectUserSid equals the TargetSid (self-modification), the new UPN value is not a standard UPN (no @ sign), and the value is not a Windows placeholder.
A non-UPN value set on one's own account is anomalous and has no legitimate administrative use case.
Windows Kerberos Local Successful Logon: endpointEndpointNoneversion:16
The following analytic identifies a local successful authentication event on a Windows endpoint using the Kerberos package.
It detects EventCode 4624 with LogonType 3 and source address 127.0.0.1, indicating a login to the built-in local Administrator account.
This activity is significant as it may suggest a Kerberos relay attack, a method attackers use to escalate privileges.
If confirmed malicious, this could allow an attacker to gain unauthorized access to sensitive systems, execute arbitrary code, or create new accounts in Active Directory, leading to potential system compromise.
Windows PowerView Constrained Delegation Discovery: endpointEndpointNoneversion:11
The following analytic detects the use of PowerView commandlets to discover Windows endpoints with Kerberos Constrained Delegation. It leverages PowerShell Script Block Logging (EventCode=4104) to identify specific commandlets like `Get-DomainComputer` or `Get-NetComputer` with the `-TrustedToAuth` parameter. This activity is significant as it indicates potential reconnaissance efforts by adversaries or Red Teams to map out privileged delegation settings in Active Directory. If confirmed malicious, this could allow attackers to identify high-value targets for further exploitation, potentially leading to privilege escalation or lateral movement within the network.
Suspicious Kerberos Service Ticket Request: endpointEndpointNoneversion:12
The following analytic detects suspicious Kerberos Service Ticket (TGS) requests where the requesting account name matches the service name, potentially indicating an exploitation attempt of CVE-2021-42278 and CVE-2021-42287. This detection leverages Event ID 4769 from Domain Controller and Kerberos events. Such activity is significant as it may represent an adversary attempting to escalate privileges by impersonating a domain controller. If confirmed malicious, this could allow an attacker to take control of the domain controller, leading to complete domain compromise and unauthorized access to sensitive information.
Windows PowerView Kerberos Service Ticket Request: endpointEndpointNoneversion:11
The following analytic detects the execution of the `Get-DomainSPNTicket` commandlet, part of the PowerView tool, by leveraging PowerShell Script Block Logging (EventCode=4104). This commandlet requests Kerberos service tickets for specified service principal names (SPNs). Monitoring this activity is crucial as it can indicate attempts to perform Kerberoasting, a technique used to extract SPN account passwords via cracking tools like hashcat. If confirmed malicious, this activity could allow attackers to gain unauthorized access to sensitive accounts, potentially leading to privilege escalation and further network compromise.
Windows Computer Account Created by Computer Account: endpointEndpointNoneversion:10
The following analytic identifies a computer account creating a new computer account with a specific Service Principal Name (SPN) "RestrictedKrbHost". This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify such activities. This behavior is significant as it may indicate an attempt to establish unauthorized Kerberos authentication channels, potentially leading to lateral movement or privilege escalation. If confirmed malicious, this activity could allow an attacker to impersonate services, access sensitive information, or maintain persistence within the network.
Windows Multiple Disabled Users Failed To Authenticate Wth Kerberos: endpointEndpointNoneversion:12
The following analytic detects a single source endpoint failing to authenticate with 30 unique disabled domain users using the Kerberos protocol within 5 minutes. It leverages Windows Security Event 4768, focusing on failure code `0x12`, indicating revoked credentials. This activity is significant as it may indicate a Password Spraying attack targeting disabled accounts, a tactic used by adversaries to gain initial access or elevate privileges. If confirmed malicious, this could lead to unauthorized access or privilege escalation within the Active Directory environment, posing a severe security risk.
Windows Computer Account With SPN: endpointEndpointNoneversion:11
The following analytic detects the addition of Service Principal Names (SPNs) HOST and RestrictedKrbHost to a computer account, indicative of KrbRelayUp behavior. This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify changes in SPNs. This activity is significant as it is commonly associated with Kerberos-based attacks, which can be used to escalate privileges or perform lateral movement within a network. If confirmed malicious, this behavior could allow an attacker to impersonate services, potentially leading to unauthorized access to sensitive resources.
Windows PowerView SPN Discovery: endpointEndpointNoneversion:12
The following analytic detects the execution of the `Get-DomainUser` or `Get-NetUser` PowerShell cmdlets with the `-SPN` parameter, indicating the use of PowerView for SPN discovery. It leverages PowerShell Script Block Logging (EventCode=4104) to identify these specific commands. This activity is significant as it suggests an attempt to enumerate domain accounts associated with Service Principal Names (SPNs), a common precursor to Kerberoasting attacks. If confirmed malicious, this could allow an attacker to identify and target accounts for credential theft, potentially leading to unauthorized access and privilege escalation within the network.
Unusual Number of Computer Service Tickets Requested: endpointEndpointNoneversion:9
The following analytic identifies an unusual number of computer service ticket requests from a single source, leveraging Event ID 4769, "A Kerberos service ticket was requested." It uses statistical analysis, including standard deviation and the 3-sigma rule, to detect anomalies in service ticket requests. This activity is significant as it may indicate malicious behavior such as lateral movement, malware staging, or reconnaissance. If confirmed malicious, an attacker could gain unauthorized access to multiple endpoints, facilitating further compromise and potential data exfiltration.
Windows Process With NetExec Command Line Parameters: endpointEndpointNoneversion:11
The following analytic detects the use of NetExec (formally CrackmapExec) a toolset used for post-exploitation enumeration and attack within Active Directory environments through command line parameters. It leverages Endpoint Detection and Response (EDR) data to identify specific command-line arguments associated with actions like ticket manipulation, kerberoasting, and password spraying. This activity is significant as NetExec is used by adversaries to exploit Kerberos for privilege escalation and lateral movement. If confirmed malicious, this could lead to unauthorized access, persistence, and potential compromise of sensitive information within the network.
ServicePrincipalNames Discovery with SetSPN: endpointEndpointNoneversion:13
The following analytic detects the use of `setspn.exe` to query the domain for Service Principal Names (SPNs). This detection leverages Endpoint Detection and Response (EDR) data, focusing on specific command-line arguments associated with `setspn.exe`. Monitoring this activity is crucial as it often precedes Kerberoasting or Silver Ticket attacks, which can lead to credential theft. If confirmed malicious, an attacker could use the gathered SPNs to escalate privileges or persist within the environment, posing a significant security risk.
Disabled Kerberos Pre-Authentication Discovery With PowerView: endpointEndpointNoneversion:15
The following analytic detects the execution of the `Get-DomainUser` commandlet with the `-PreauthNotRequired` parameter using PowerShell Script Block Logging (EventCode=4104). This command is part of PowerView, a tool used for enumerating Windows Active Directory networks. Identifying domain accounts with Kerberos Pre-Authentication disabled is significant because adversaries can leverage this information to attempt offline password cracking. If confirmed malicious, this activity could lead to unauthorized access to domain accounts, potentially compromising sensitive information and escalating privileges within the network.
Windows Unusual Count Of Users Failed To Auth Using Kerberos: endpointEndpointNoneversion:11
The following analytic identifies a source endpoint failing to authenticate multiple valid users using the Kerberos protocol, potentially indicating a Password Spraying attack. It leverages Event 4771, which is generated when the Key Distribution Center fails to issue a Kerberos Ticket Granting Ticket (TGT) due to a wrong password (failure code 0x18). This detection uses statistical analysis, specifically the 3-sigma rule, to identify unusual authentication failures. If confirmed malicious, this activity could allow an attacker to gain initial access or elevate privileges within an Active Directory environment.
Windows Get-AdComputer Unconstrained Delegation Discovery: endpointEndpointNoneversion:12
The following analytic detects the use of the Get-ADComputer cmdlet with parameters indicating a search for Windows endpoints with Kerberos Unconstrained Delegation. It leverages PowerShell Script Block Logging (EventCode=4104) to identify this specific activity. This behavior is significant as it may indicate an attempt by adversaries or Red Teams to gain situational awareness and perform Active Directory discovery. If confirmed malicious, this activity could allow attackers to identify high-value targets for further exploitation, potentially leading to privilege escalation or lateral movement within the network.
Unknown Process Using The Kerberos Protocol: endpointEndpointNoneversion:12
The following analytic identifies a non-lsass.exe process making an outbound connection on port 88, which is typically used by the Kerberos authentication protocol. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and network traffic logs. This activity is significant because, under normal circumstances, only the lsass.exe process should interact with the Kerberos Distribution Center. If confirmed malicious, this behavior could indicate an adversary attempting to abuse the Kerberos protocol, potentially leading to unauthorized access or lateral movement within the network.
Rubeus Command Line Parameters: endpointEndpointNoneversion:13
The following analytic detects the use of Rubeus command line parameters, a toolset for Kerberos attacks within Active Directory environments. It leverages Endpoint Detection and Response (EDR) data to identify specific command-line arguments associated with actions like ticket manipulation, kerberoasting, and password spraying. This activity is significant as Rubeus is commonly used by adversaries to exploit Kerberos for privilege escalation and lateral movement. If confirmed malicious, this could lead to unauthorized access, persistence, and potential compromise of sensitive information within the network.
Windows AD SPN Unicode Collision Injection: endpointEndpointNoneversion:1
The following analytic detects the addition or modification of a servicePrincipalName (SPN) containing invisible Unicode characters to an Active Directory computer object via Windows Security Event 5136.
This is the key indicator of the KerberLoss attack (CVE-2026-25177), where an attacker with write access to a machine account's SPN attribute injects a collision SPN that contains a Zero Width or other invisible Unicode character (e.g. U+200C Zero Width Non-Joiner).
LDAP's string preparation rules (RFC 4518) cause these characters to be ignored during uniqueness checking, allowing the write to succeed even when an identical SPN already exists on another machine account.
The Kerberos KDC, however, does not apply the same normalisation — it finds two accounts with matching SPNs and returns KDC_ERR_S_PRINCIPAL_UNKNOWN, causing a Kerberos denial-of-service or forcing clients to fall back to NTLM downgrade.
Suspicious Ticket Granting Ticket Request: endpointEndpointNoneversion:10
The following analytic detects suspicious Kerberos Ticket Granting Ticket (TGT) requests that may indicate exploitation of CVE-2021-42278 and CVE-2021-42287. It leverages Event ID 4781 (account name change) and Event ID 4768 (TGT request) to identify sequences where a newly renamed computer account requests a TGT. This behavior is significant as it could represent an attempt to escalate privileges by impersonating a Domain Controller. If confirmed malicious, this activity could allow attackers to gain elevated access and potentially control over the domain environment.
Kerberos User Enumeration: endpointEndpointNoneversion:13
The following analytic detects an unusual number of Kerberos Ticket Granting Ticket (TGT) requests for non-existing users from a single source endpoint. It leverages Event ID 4768 and identifies anomalies using the 3-sigma statistical rule. This behavior is significant as it may indicate an adversary performing a user enumeration attack against Active Directory. If confirmed malicious, the attacker could validate a list of usernames, potentially leading to further attacks such as brute force or credential stuffing, compromising the security of the environment.
Windows AD Computer SPN Modified By User Account: endpointEndpointNoneversion:1
The following analytic detects a user account (non-machine account) adding or removing a servicePrincipalName (SPN) on a computer object in Active Directory, via Windows Security Event 5136.
In normal AD operations, SPN values on computer objects are managed exclusively by the computer account itself (during domain join or name change), by Domain Controllers during replication, or by the SYSTEM/NETWORK SERVICE context — all of which appear as accounts ending in the dollar sign ($) convention.
A named user account writing to the servicePrincipalName attribute of a computer object is anomalous and may indicate an attacker with delegated WriteProperty rights over computer accounts performing SPN manipulation.
PetitPotam Suspicious Kerberos TGT Request: endpointEndpointNoneversion:11
The following analytic detects a suspicious Kerberos Ticket Granting Ticket (TGT) request, identified by Event Code 4768. This detection leverages Windows Security Event Logs to identify TGT requests with unusual fields, which may indicate the use of tools like Rubeus following the exploitation of CVE-2021-36942 (PetitPotam). This activity is significant as it can signal an attacker leveraging a compromised certificate to request Kerberos tickets, potentially leading to unauthorized access. If confirmed malicious, this could allow attackers to escalate privileges and persist within the environment, posing a severe security risk.
Unusual Number of Kerberos Service Tickets Requested: endpointEndpointNoneversion:14
The following analytic identifies an unusual number of Kerberos service ticket requests, potentially indicating a kerberoasting attack. It leverages Kerberos Event 4769 and calculates the standard deviation for each host, using the 3-sigma rule to detect anomalies. This activity is significant as kerberoasting allows adversaries to request service tickets and crack them offline, potentially gaining privileged access to the domain. If confirmed malicious, this could lead to unauthorized access to sensitive accounts and escalation of privileges within the Active Directory environment.
Windows Unusual Count Of Invalid Users Fail To Auth Using Kerberos: endpointEndpointNoneversion:11
The following analytic identifies a source endpoint failing to authenticate with multiple invalid domain users using the Kerberos protocol. It leverages Event ID 4768, which is generated when the Key Distribution Center issues a Kerberos Ticket Granting Ticket (TGT) and detects failure code 0x6, indicating the user is not found in the Kerberos database. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges. If confirmed malicious, this activity could lead to unauthorized access and potential privilege escalation within the Active Directory environment.
Windows Unusual Count Of Disabled Users Failed Auth Using Kerberos: endpointEndpointNoneversion:11
The following analytic identifies a source endpoint failing to authenticate with multiple disabled domain users using the Kerberos protocol. It leverages EventCode 4768, which is generated when the Key Distribution Center issues a Kerberos Ticket Granting Ticket (TGT) and detects failure code `0x12` (credentials revoked). This behavior is significant as it may indicate a Password Spraying attack targeting disabled accounts, potentially leading to initial access or privilege escalation. If confirmed malicious, attackers could gain unauthorized access or elevate privileges within the Active Directory environment.
Windows Computer Account Requesting Kerberos Ticket: endpointEndpointNoneversion:10
The following analytic detects a computer account requesting a Kerberos ticket, which is unusual as typically user accounts request these tickets. This detection leverages Windows Security Event Logs, specifically EventCode 4768, to identify instances where the TargetUserName ends with a dollar sign ($), indicating a computer account. This activity is significant because it may indicate the use of tools like KrbUpRelay or other Kerberos-based attacks. If confirmed malicious, this could allow attackers to impersonate computer accounts, potentially leading to unauthorized access and lateral movement within the network.
Windows PowerView Unconstrained Delegation Discovery: endpointEndpointNoneversion:11
The following analytic detects the use of PowerView commandlets to discover Windows endpoints with Kerberos Unconstrained Delegation. It leverages PowerShell Script Block Logging (EventCode=4104) to identify specific commands like `Get-DomainComputer` or `Get-NetComputer` with the `-Unconstrained` parameter. This activity is significant as it indicates potential reconnaissance efforts by adversaries or Red Teams to map out privileged delegation settings in Active Directory. If confirmed malicious, this could allow attackers to identify high-value targets for further exploitation, potentially leading to privilege escalation or lateral movement within the network.
