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Introduction:
Microsoft’s Advanced Hunting now integrates identity‑focused predefined scenarios that map attack paths across hybrid environments. These scenarios surface Kerberoast and AS‑REP roast vulnerabilities, domain compromise routes, OAuth application misconfigurations, and external user access risks—giving defenders a proactive graph‑based view of credential exposure and privilege escalation chains.
Learning Objectives:
- Identify and simulate Kerberoast and AS‑REP roast attack paths using Advanced Hunting queries.
- Detect risky OAuth applications and external user access to cloud resources.
- Apply Linux/Windows commands for hardening and real‑time mitigation.
You Should Know:
1. Hunting Kerberoast Attack Paths with KQL
Kerberoast targets service accounts with weak encryption. Attackers request a service ticket (TGS) for a service, crack it offline, then impersonate the service. Advanced Hunting tracks this via `IdentityLogonEvents` and IdentityQueryEvents.
Step‑by‑step guide to hunt Kerberoast:
- Use this KQL query in Microsoft 365 Defender Advanced Hunting:
IdentityQueryEvents | where ActionType == "Kerberos service ticket requested" | where AdditionalFields has "RC4" or AdditionalFields has "AES256" | summarize Count = count() by AccountName, TargetService, Timestamp | order by Count desc
- Correlate with high‑volume requests from a single account to a non‑interactive service.
- On Linux (attacker simulation):
Using Impacket GetUserSPNs to request tickets impacket-GetUserSPNs -request -dc-ip <DC_IP> <DOMAIN>/<USER>
- On Windows (mitigation):
List all service accounts with RC4 encryption Get-ADUser -Filter {ServicePrincipalName -like ""} -Properties ServicePrincipalName, KerberosEncryptionType | Where-Object { $_.KerberosEncryptionType -ne "AES256" } Force AES encryption via Group Policy Set-ADUser -Identity <ServiceAccount> -KerberosEncryptionType AES256
2. Detecting AS‑REP Roast Attacks
AS‑REP roast abuses accounts with `Do not require Kerberos preauthentication` enabled. Attackers request an AS‑REP, extract the encrypted timestamp, and crack it offline.
Step‑by‑step guide:
- Advanced Hunting query for AS‑REP roast:
IdentityLogonEvents | where ActionType == "Kerberos authentication ticket (AS) requested" | where AdditionalFields has "No preauthentication" | project Timestamp, AccountName, TargetDeviceName, IPAddress
- Simulate on Linux:
impacket-GetNPUsers -dc-ip <DC_IP> <DOMAIN>/ -usersfile users.txt -format hashcat -outputfile asreproast.txt
- Mitigation on Windows (find vulnerable accounts):
Get-ADUser -Filter {DoesNotRequirePreAuth -eq $true} -Properties DoesNotRequirePreAuth | ForEach-Object { Set-ADUser -Identity $_.SamAccountName -DoesNotRequirePreAuth $false }
3. Uncovering OAuth Application Risks
Malicious OAuth apps can grant persistent access to cloud data without passwords. Look for apps with high privileges (e.g., Mail.Read, Files.ReadWrite.All) added by non‑admin users.
Step‑by‑step guide:
- Advanced Hunting for OAuth app consent:
CloudAppEvents | where Application == "Azure Active Directory" | where ActionType == "Consent to application" | where RawEventData has "scope" and RawEventData has "Mail.Read" or RawEventData has "Files.ReadWrite.All" | project Timestamp, AccountObjectId, TargetAppName, RawEventData.scope
- Use Microsoft Graph PowerShell to audit:
Connect-MgGraph -Scopes "Application.Read.All", "Directory.Read.All" Get-MgServicePrincipal | Where-Object {$_.AppDisplayName -like "malicious"} | Format-List - Revoke risky apps:
Remove-MgServicePrincipal -ServicePrincipalId <ID>
4. External User Access Risks to Cloud Resources
External identities (guests, partners) often over‑provisioned. Attackers pivot from compromised external accounts to internal resources.
Step‑by‑step guide:
- Hunt with KQL for external access anomalies:
AADSignInEventsBeta | where IsExternalUser == true | where Application == "SharePoint Online" or Application == "Azure Portal" | where RiskLevelDuringSignIn == "high" | summarize by UserPrincipalName, IPAddress, Timestamp
- Mitigate using Conditional Access:
PowerShell to block external access to sensitive apps New-AzureADPolicy -Definition @('{"BlockExternalUsers":true}') -DisplayName "BlockExternalSensitiveApps" -Type "ConditionalAccess"
- Domain Compromise Routes: Golden Ticket & Skeleton Key Detection
Attackers who compromise KRBTGT account hash can forge Golden Tickets. Hunt for anomalous TGT lifetimes (default 10 hours) or unusual service requests.
Step‑by‑step guide:
- Advanced Hunting for golden ticket:
IdentityLogonEvents | where ActionType == "Kerberos ticket granted" | where TicketLifetime > 10h | where AccountName != "KRBTGT" | summarize by AccountName, TargetDeviceName, TicketLifetime
- On Domain Controller, monitor Event ID 4769 (service ticket requested) with unusual encryption (0x17 for RC4).
- Reset KRBTGT password twice (Microsoft recommended):
Reset-ADAccountPassword -Identity krbtgt -NewPassword (ConvertTo-SecureString -AsPlainText "NewComplexP@ss" -Force)
6. Linux & Windows Commands for Real‑Time Hardening
| Platform | Command | Purpose |
|-|||
| Windows | `klist purge` | Purge Kerberos tickets after incident |
| Windows | `Get-WinEvent -LogName Security \| Where-Object {$_.Id -eq 4769 -and $_.Message -like “RC4”}` | Find RC4 ticket requests |
| Linux | `sudo tcpdump -i eth0 kerberos` | Capture Kerberos traffic for analysis |
| Linux | `python3 /usr/share/doc/python3-impacket/examples/GetUserSPNs.py -request` | Test for Kerberoastable accounts |
- API Security & Cloud Hardening for Identity Scenarios
OAuth tokens and service principals often use misconfigured APIs. Validate token issuance and restrict API permissions.
Step‑by‑step guide:
- Audit Azure AD app permissions via API:
curl -X GET "https://graph.microsoft.com/v1.0/servicePrincipals?$filter=tags/any(x:x eq 'WindowsAzureActiveDirectoryIntegratedApp')" -H "Authorization: Bearer <token>"
- Enforce `Managed Identity` instead of static credentials for Azure resources.
- Use Azure Policy to block apps with `Application.ReadWrite.All` scope.
What Undercode Say:
- Key Takeaway 1: Identity attacks are no longer theoretical—predefined hunting graphs give defenders a real‑time map of Kerberoast, AS‑REP roast, and OAuth abuse paths.
- Key Takeaway 2: Combining KQL hunting with actionable Windows/Linux commands (e.g.,
impacket,Get-ADUser,klist) turns detection into automated response loops. - Analysis: The industry shift from reactive alerting to proactive graph‑based hunting is inevitable. Microsoft’s integration of identity scenarios lowers the barrier for SOC teams, but requires continuous tuning to avoid false positives. Attackers will counter by blending privileged access with non‑Kerberos protocols (e.g., OAuth2 token theft). Defenders must prioritize AES enforcement, preauthentication checks, and external user lifecycle governance.
Prediction:
By 2027, graph‑based identity hunting will be a standard SOC module, driven by AI‑generated attack path simulations. However, threat actors will shift focus to abusing OAuth device code flows and cross‑tenant app consents—bypassing traditional Kerberos controls. Organizations failing to integrate identity analytics with endpoint detection will suffer supply‑chain identity breaches originating from compromised external identities. Expect Microsoft to release automated remediation playbooks for the exact scenarios listed here within the next 12 months.
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IT/Security Reporter URL:
Reported By: Markolauren Identity – Hackers Feeds
Extra Hub: Undercode MoN
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