GitHub
Page cover

Week 1. EscapeTwo

SUMMARY

This a Windows Server 2019 running as domain controller. In a shared resource we find an XLSX file containing the MSSQL's sa account password in clear text. This allows to get an initial shell in the system. Once inside the system, we find a password in an MSSQL configuration file, that can be used to move laterally and collect the user flag.

Regarding escalation, we enumerate the AD with BloodHound CE and discover a permissive edge that allows a shadow credential attack and a lateral movement. Under the new context, we enumerate vulnerable AD CS templates and find one vulnerable to ESC4, which can be abused to dump the administrator's hash.

KEYWORDS

MSSQL, Impacket, mssqlclient.py, xp_cmdshell, owneredit.py, dacledit.py, shadow credentials attack, Certipy, Active Directory Certificate Services (AD CS), ESC4, ESC1.

ENUMERATION

Port scan.

> for ports in $(nmap $target -p- --min-rate=5000 -Pn --open --reason | grep open | awk -F "/" '{print $1}' | tr '\n' ',' | sed s/,$//); do nmap $target -p$ports -sV -sC -Pn -vv -n && echo "\nList of open ports: $ports";done
 
Nmap scan report for 10.10.11.51
Host is up, received user-set (0.058s latency).
Scanned at 2025-01-19 12:37:19 GMT for 101s
PORT      STATE SERVICE       REASON  VERSION
53/tcp    open  domain        syn-ack Simple DNS Plus
88/tcp    open  kerberos-sec  syn-ack Microsoft Windows Kerberos (server time: 2025-01-19 12:38:39Z)
135/tcp   open  msrpc         syn-ack Microsoft Windows RPC
139/tcp   open  netbios-ssn   syn-ack Microsoft Windows netbios-ssn
389/tcp   open  ldap          syn-ack Microsoft Windows Active Directory LDAP (Domain: sequel.htb0., Site: Default-First-Site-Name)
| ssl-cert: Subject: commonName=DC01.sequel.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1::<unsupported>, DNS:DC01.sequel.htb
| Issuer: commonName=sequel-DC01-CA/domainComponent=sequel
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2024-06-08T17:35:00
| Not valid after:  2025-06-08T17:35:00
| MD5:   09fd3df49f58da05410de89e7442b6ff
| SHA-1: c3ac8bfd6132ed7729757f5e69901ced528eaac5
| -----BEGIN CERTIFICATE-----
| MIIGJjCCBQ6gAwIBAgITVAAAAANDveocXlnSDQAAAAAAAzANBgkqhkiG9w0BAQsF
| ADBGMRMwEQYKCZImiZPyLGQBGRYDaHRiMRYwFAYKCZImiZPyLGQBGRYGc2VxdWVs
| MRcwFQYDVQQDEw5zZXF1ZWwtREMwMS1DQTAeFw0yNDA2MDgxNzM1MDBaFw0yNTA2
| MDgxNzM1MDBaMBoxGDAWBgNVBAMTD0RDMDEuc2VxdWVsLmh0YjCCASIwDQYJKoZI
| hvcNAQEBBQADggEPADCCAQoCggEBANRCnm8pZ86LZP3kAtl29rFgY5gEOEXSCZSm
| F6Ai+1vh6a8LrCRKMWtC8+Kla0PXgjTcGcmDawcI8h0BsaSH6sQVAD21ca5MQcv0
| xf+4TzrvAnp9H+pVHO1r42cLXBwq14Ak8dSueiOLgxoLKO1CDtKk+e8ZxQWf94Bp
| Vu8rnpImFT6IeDgACeBfb0hLzK2JJRT9ezZiUVxoTfMKKuy4IPFWcshW/1bQfEK0
| ExOcQZVaoCJzRPBUVTp/XGHEW9d6abW8h1UR+64qVfGexsrUKBfxKRsHuHTxa4ts
| +qUVJRbJkzlSgyKGMjhNfT3BPVwwP8HvErWvbsWKKPRkvMaPhU0CAwEAAaOCAzcw
| ggMzMC8GCSsGAQQBgjcUAgQiHiAARABvAG0AYQBpAG4AQwBvAG4AdAByAG8AbABs
| AGUAcjAdBgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwEwDgYDVR0PAQH/BAQD
| AgWgMHgGCSqGSIb3DQEJDwRrMGkwDgYIKoZIhvcNAwICAgCAMA4GCCqGSIb3DQME
| AgIAgDALBglghkgBZQMEASowCwYJYIZIAWUDBAEtMAsGCWCGSAFlAwQBAjALBglg
| hkgBZQMEAQUwBwYFKw4DAgcwCgYIKoZIhvcNAwcwHQYDVR0OBBYEFNfVXsrpSahW
| xfdL4wxFDgtUztvRMB8GA1UdIwQYMBaAFMZBubbkDkfWBlps8YrGlP0a+7jDMIHI
| BgNVHR8EgcAwgb0wgbqggbeggbSGgbFsZGFwOi8vL0NOPXNlcXVlbC1EQzAxLUNB
| LENOPURDMDEsQ049Q0RQLENOPVB1YmxpYyUyMEtleSUyMFNlcnZpY2VzLENOPVNl
| cnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERDPWh0Yj9jZXJ0aWZp
| Y2F0ZVJldm9jYXRpb25MaXN0P2Jhc2U/b2JqZWN0Q2xhc3M9Y1JMRGlzdHJpYnV0
| aW9uUG9pbnQwgb8GCCsGAQUFBwEBBIGyMIGvMIGsBggrBgEFBQcwAoaBn2xkYXA6
| Ly8vQ049c2VxdWVsLURDMDEtQ0EsQ049QUlBLENOPVB1YmxpYyUyMEtleSUyMFNl
| cnZpY2VzLENOPVNlcnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERD
| PWh0Yj9jQUNlcnRpZmljYXRlP2Jhc2U/b2JqZWN0Q2xhc3M9Y2VydGlmaWNhdGlv
| bkF1dGhvcml0eTA7BgNVHREENDAyoB8GCSsGAQQBgjcZAaASBBDjAT1NPPfwT4sa
| sNjnBqS3gg9EQzAxLnNlcXVlbC5odGIwTQYJKwYBBAGCNxkCBEAwPqA8BgorBgEE
| AYI3GQIBoC4ELFMtMS01LTIxLTU0ODY3MDM5Ny05NzI2ODc0ODQtMzQ5NjMzNTM3
| MC0xMDAwMA0GCSqGSIb3DQEBCwUAA4IBAQCBDjlZZbFac6RlhZ2BhLzvWmA1Xcyn
| jZmYF3aOXmmof1yyO/kxk81fStsu3gtZ94KmpkBwmd1QkSJCuT54fTxg17xDtA49
| QF7O4DPsFkeOM2ip8TAf8x5bGwH5tlZvNjllBCgSpCupZlNY8wKYnyKQDNwtWtgL
| UF4SbE9Q6JWA+Re5lPa6AoUr/sRzKxcPsAjK8kgquUA0spoDrxAqkADIRsHgBLGY
| +Wn+DXHctZtv8GcOwrfW5KkbkVykx8DSS2qH4y2+xbC3ZHjsKlVjoddkjEkrHku0
| 2iXZSIqShMXzXmLTW/G+LzqK3U3VTcKo0yUKqmLlKyZXzQ+kYVLqgOOX
|_-----END CERTIFICATE-----
|_ssl-date: 2025-01-19T12:40:16+00:00; +1m17s from scanner time.
445/tcp   open  microsoft-ds? syn-ack
464/tcp   open  kpasswd5?     syn-ack
593/tcp   open  ncacn_http    syn-ack Microsoft Windows RPC over HTTP 1.0
636/tcp   open  ssl/ldap      syn-ack Microsoft Windows Active Directory LDAP (Domain: sequel.htb0., Site: Default-First-Site-Name)
| ssl-cert: Subject: commonName=DC01.sequel.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1::<unsupported>, DNS:DC01.sequel.htb
| Issuer: commonName=sequel-DC01-CA/domainComponent=sequel
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2024-06-08T17:35:00
| Not valid after:  2025-06-08T17:35:00
| MD5:   09fd3df49f58da05410de89e7442b6ff
| SHA-1: c3ac8bfd6132ed7729757f5e69901ced528eaac5
| -----BEGIN CERTIFICATE-----
| MIIGJjCCBQ6gAwIBAgITVAAAAANDveocXlnSDQAAAAAAAzANBgkqhkiG9w0BAQsF
| ADBGMRMwEQYKCZImiZPyLGQBGRYDaHRiMRYwFAYKCZImiZPyLGQBGRYGc2VxdWVs
| MRcwFQYDVQQDEw5zZXF1ZWwtREMwMS1DQTAeFw0yNDA2MDgxNzM1MDBaFw0yNTA2
| MDgxNzM1MDBaMBoxGDAWBgNVBAMTD0RDMDEuc2VxdWVsLmh0YjCCASIwDQYJKoZI
| hvcNAQEBBQADggEPADCCAQoCggEBANRCnm8pZ86LZP3kAtl29rFgY5gEOEXSCZSm
| F6Ai+1vh6a8LrCRKMWtC8+Kla0PXgjTcGcmDawcI8h0BsaSH6sQVAD21ca5MQcv0
| xf+4TzrvAnp9H+pVHO1r42cLXBwq14Ak8dSueiOLgxoLKO1CDtKk+e8ZxQWf94Bp
| Vu8rnpImFT6IeDgACeBfb0hLzK2JJRT9ezZiUVxoTfMKKuy4IPFWcshW/1bQfEK0
| ExOcQZVaoCJzRPBUVTp/XGHEW9d6abW8h1UR+64qVfGexsrUKBfxKRsHuHTxa4ts
| +qUVJRbJkzlSgyKGMjhNfT3BPVwwP8HvErWvbsWKKPRkvMaPhU0CAwEAAaOCAzcw
| ggMzMC8GCSsGAQQBgjcUAgQiHiAARABvAG0AYQBpAG4AQwBvAG4AdAByAG8AbABs
| AGUAcjAdBgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwEwDgYDVR0PAQH/BAQD
| AgWgMHgGCSqGSIb3DQEJDwRrMGkwDgYIKoZIhvcNAwICAgCAMA4GCCqGSIb3DQME
| AgIAgDALBglghkgBZQMEASowCwYJYIZIAWUDBAEtMAsGCWCGSAFlAwQBAjALBglg
| hkgBZQMEAQUwBwYFKw4DAgcwCgYIKoZIhvcNAwcwHQYDVR0OBBYEFNfVXsrpSahW
| xfdL4wxFDgtUztvRMB8GA1UdIwQYMBaAFMZBubbkDkfWBlps8YrGlP0a+7jDMIHI
| BgNVHR8EgcAwgb0wgbqggbeggbSGgbFsZGFwOi8vL0NOPXNlcXVlbC1EQzAxLUNB
| LENOPURDMDEsQ049Q0RQLENOPVB1YmxpYyUyMEtleSUyMFNlcnZpY2VzLENOPVNl
| cnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERDPWh0Yj9jZXJ0aWZp
| Y2F0ZVJldm9jYXRpb25MaXN0P2Jhc2U/b2JqZWN0Q2xhc3M9Y1JMRGlzdHJpYnV0
| aW9uUG9pbnQwgb8GCCsGAQUFBwEBBIGyMIGvMIGsBggrBgEFBQcwAoaBn2xkYXA6
| Ly8vQ049c2VxdWVsLURDMDEtQ0EsQ049QUlBLENOPVB1YmxpYyUyMEtleSUyMFNl
| cnZpY2VzLENOPVNlcnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERD
| PWh0Yj9jQUNlcnRpZmljYXRlP2Jhc2U/b2JqZWN0Q2xhc3M9Y2VydGlmaWNhdGlv
| bkF1dGhvcml0eTA7BgNVHREENDAyoB8GCSsGAQQBgjcZAaASBBDjAT1NPPfwT4sa
| sNjnBqS3gg9EQzAxLnNlcXVlbC5odGIwTQYJKwYBBAGCNxkCBEAwPqA8BgorBgEE
| AYI3GQIBoC4ELFMtMS01LTIxLTU0ODY3MDM5Ny05NzI2ODc0ODQtMzQ5NjMzNTM3
| MC0xMDAwMA0GCSqGSIb3DQEBCwUAA4IBAQCBDjlZZbFac6RlhZ2BhLzvWmA1Xcyn
| jZmYF3aOXmmof1yyO/kxk81fStsu3gtZ94KmpkBwmd1QkSJCuT54fTxg17xDtA49
| QF7O4DPsFkeOM2ip8TAf8x5bGwH5tlZvNjllBCgSpCupZlNY8wKYnyKQDNwtWtgL
| UF4SbE9Q6JWA+Re5lPa6AoUr/sRzKxcPsAjK8kgquUA0spoDrxAqkADIRsHgBLGY
| +Wn+DXHctZtv8GcOwrfW5KkbkVykx8DSS2qH4y2+xbC3ZHjsKlVjoddkjEkrHku0
| 2iXZSIqShMXzXmLTW/G+LzqK3U3VTcKo0yUKqmLlKyZXzQ+kYVLqgOOX
|_-----END CERTIFICATE-----
|_ssl-date: 2025-01-19T12:40:16+00:00; +1m17s from scanner time.
1433/tcp  open  ms-sql-s      syn-ack Microsoft SQL Server 2019 15.00.2000.00; RTM
|_ssl-date: 2025-01-19T12:40:16+00:00; +1m17s from scanner time.
| ssl-cert: Subject: commonName=SSL_Self_Signed_Fallback
| Issuer: commonName=SSL_Self_Signed_Fallback
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2025-01-18T18:40:12
| Not valid after:  2055-01-18T18:40:12
| MD5:   85f1791dca227d5a5c6f7600dad57dad
| SHA-1: 4724c7db5f1c2fdb9e4670a64895e728de85171e
| -----BEGIN CERTIFICATE-----
| MIIDADCCAeigAwIBAgIQHeU6tFZApItE1TBh0S85lTANBgkqhkiG9w0BAQsFADA7
| MTkwNwYDVQQDHjAAUwBTAEwAXwBTAGUAbABmAF8AUwBpAGcAbgBlAGQAXwBGAGEA
| bABsAGIAYQBjAGswIBcNMjUwMTE4MTg0MDEyWhgPMjA1NTAxMTgxODQwMTJaMDsx
| OTA3BgNVBAMeMABTAFMATABfAFMAZQBsAGYAXwBTAGkAZwBuAGUAZABfAEYAYQBs
| AGwAYgBhAGMAazCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBALc6C9kY
| sFYn2KT6RED682MNEWGAihfdLMlBXHXBwfeGq+0Ekj2CQdX1t+MBgsWbcXyhFqut
| 2a+K9QAA3uLoYD/skIRVr13XdZMtGXz2q/Td2D0UD+UVmpUcG4KAu37LHyWc7z0W
| M0TeLGalIcvZCoz34b6V0cPQS3O6tGFPkqNa8V2VnuKEe6NtBk5uxi2uCdhnxEeN
| RM9NcflJ4ZKUPBukCxrxl7d440Ri9sZ2VaHfnR7BJq6ynqDuwM2FEWgHusf9s0dK
| OOmWz7PFVT1T2GgTf8FYoYHgWGGmM/YQCieY0GFeKTEJ53XGBpqwZHJ0BXgLbj3K
| ZWXapzr2eszCD40CAwEAATANBgkqhkiG9w0BAQsFAAOCAQEAqZNdKbRXoK0PZhf7
| x6DQgQBMRJwaHf8UqsOtGzQCNjboVJ7NlJkOsGaxoTOQAAFZX5BGJzxA+9EpKKoG
| 0paUvuEFPChIe45h2rfIwNeCpoIDnDn8zbKQvKDDwz5/f6v4+8mtdcygUXnt4iXX
| a6jPCXzHkPuND1V2QgCmr6gs1KpBCLX6fjyTMvzOA5fG1K/p6CMAF4bP2vvJ4NLA
| tKdJMtlj8XI32rYczM54VvTGGoyo7HnE4JZeZm3gx/OBcTZB8d6j3VMpoZFsZDeL
| XWqGAW3I0wjKl9gqzTBfc16SkyEcxTfGQ1kRGn6F7gwGn6G8+yQM9mbgjILt/G9e
| KbAmWQ==
|_-----END CERTIFICATE-----
|_ms-sql-ntlm-info: ERROR: Script execution failed (use -d to debug)
|_ms-sql-info: ERROR: Script execution failed (use -d to debug)
3268/tcp  open  ldap          syn-ack Microsoft Windows Active Directory LDAP (Domain: sequel.htb0., Site: Default-First-Site-Name)
| ssl-cert: Subject: commonName=DC01.sequel.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1::<unsupported>, DNS:DC01.sequel.htb
| Issuer: commonName=sequel-DC01-CA/domainComponent=sequel
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2024-06-08T17:35:00
| Not valid after:  2025-06-08T17:35:00
| MD5:   09fd3df49f58da05410de89e7442b6ff
| SHA-1: c3ac8bfd6132ed7729757f5e69901ced528eaac5
| -----BEGIN CERTIFICATE-----
| MIIGJjCCBQ6gAwIBAgITVAAAAANDveocXlnSDQAAAAAAAzANBgkqhkiG9w0BAQsF
| ADBGMRMwEQYKCZImiZPyLGQBGRYDaHRiMRYwFAYKCZImiZPyLGQBGRYGc2VxdWVs
| MRcwFQYDVQQDEw5zZXF1ZWwtREMwMS1DQTAeFw0yNDA2MDgxNzM1MDBaFw0yNTA2
| MDgxNzM1MDBaMBoxGDAWBgNVBAMTD0RDMDEuc2VxdWVsLmh0YjCCASIwDQYJKoZI
| hvcNAQEBBQADggEPADCCAQoCggEBANRCnm8pZ86LZP3kAtl29rFgY5gEOEXSCZSm
| F6Ai+1vh6a8LrCRKMWtC8+Kla0PXgjTcGcmDawcI8h0BsaSH6sQVAD21ca5MQcv0
| xf+4TzrvAnp9H+pVHO1r42cLXBwq14Ak8dSueiOLgxoLKO1CDtKk+e8ZxQWf94Bp
| Vu8rnpImFT6IeDgACeBfb0hLzK2JJRT9ezZiUVxoTfMKKuy4IPFWcshW/1bQfEK0
| ExOcQZVaoCJzRPBUVTp/XGHEW9d6abW8h1UR+64qVfGexsrUKBfxKRsHuHTxa4ts
| +qUVJRbJkzlSgyKGMjhNfT3BPVwwP8HvErWvbsWKKPRkvMaPhU0CAwEAAaOCAzcw
| ggMzMC8GCSsGAQQBgjcUAgQiHiAARABvAG0AYQBpAG4AQwBvAG4AdAByAG8AbABs
| AGUAcjAdBgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwEwDgYDVR0PAQH/BAQD
| AgWgMHgGCSqGSIb3DQEJDwRrMGkwDgYIKoZIhvcNAwICAgCAMA4GCCqGSIb3DQME
| AgIAgDALBglghkgBZQMEASowCwYJYIZIAWUDBAEtMAsGCWCGSAFlAwQBAjALBglg
| hkgBZQMEAQUwBwYFKw4DAgcwCgYIKoZIhvcNAwcwHQYDVR0OBBYEFNfVXsrpSahW
| xfdL4wxFDgtUztvRMB8GA1UdIwQYMBaAFMZBubbkDkfWBlps8YrGlP0a+7jDMIHI
| BgNVHR8EgcAwgb0wgbqggbeggbSGgbFsZGFwOi8vL0NOPXNlcXVlbC1EQzAxLUNB
| LENOPURDMDEsQ049Q0RQLENOPVB1YmxpYyUyMEtleSUyMFNlcnZpY2VzLENOPVNl
| cnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERDPWh0Yj9jZXJ0aWZp
| Y2F0ZVJldm9jYXRpb25MaXN0P2Jhc2U/b2JqZWN0Q2xhc3M9Y1JMRGlzdHJpYnV0
| aW9uUG9pbnQwgb8GCCsGAQUFBwEBBIGyMIGvMIGsBggrBgEFBQcwAoaBn2xkYXA6
| Ly8vQ049c2VxdWVsLURDMDEtQ0EsQ049QUlBLENOPVB1YmxpYyUyMEtleSUyMFNl
| cnZpY2VzLENOPVNlcnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERD
| PWh0Yj9jQUNlcnRpZmljYXRlP2Jhc2U/b2JqZWN0Q2xhc3M9Y2VydGlmaWNhdGlv
| bkF1dGhvcml0eTA7BgNVHREENDAyoB8GCSsGAQQBgjcZAaASBBDjAT1NPPfwT4sa
| sNjnBqS3gg9EQzAxLnNlcXVlbC5odGIwTQYJKwYBBAGCNxkCBEAwPqA8BgorBgEE
| AYI3GQIBoC4ELFMtMS01LTIxLTU0ODY3MDM5Ny05NzI2ODc0ODQtMzQ5NjMzNTM3
| MC0xMDAwMA0GCSqGSIb3DQEBCwUAA4IBAQCBDjlZZbFac6RlhZ2BhLzvWmA1Xcyn
| jZmYF3aOXmmof1yyO/kxk81fStsu3gtZ94KmpkBwmd1QkSJCuT54fTxg17xDtA49
| QF7O4DPsFkeOM2ip8TAf8x5bGwH5tlZvNjllBCgSpCupZlNY8wKYnyKQDNwtWtgL
| UF4SbE9Q6JWA+Re5lPa6AoUr/sRzKxcPsAjK8kgquUA0spoDrxAqkADIRsHgBLGY
| +Wn+DXHctZtv8GcOwrfW5KkbkVykx8DSS2qH4y2+xbC3ZHjsKlVjoddkjEkrHku0
| 2iXZSIqShMXzXmLTW/G+LzqK3U3VTcKo0yUKqmLlKyZXzQ+kYVLqgOOX
|_-----END CERTIFICATE-----
|_ssl-date: 2025-01-19T12:40:16+00:00; +1m17s from scanner time.
3269/tcp  open  ssl/ldap      syn-ack Microsoft Windows Active Directory LDAP (Domain: sequel.htb0., Site: Default-First-Site-Name)
|_ssl-date: 2025-01-19T12:40:16+00:00; +1m17s from scanner time.
| ssl-cert: Subject: commonName=DC01.sequel.htb
| Subject Alternative Name: othername: 1.3.6.1.4.1.311.25.1::<unsupported>, DNS:DC01.sequel.htb
| Issuer: commonName=sequel-DC01-CA/domainComponent=sequel
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2024-06-08T17:35:00
| Not valid after:  2025-06-08T17:35:00
| MD5:   09fd3df49f58da05410de89e7442b6ff
| SHA-1: c3ac8bfd6132ed7729757f5e69901ced528eaac5
| -----BEGIN CERTIFICATE-----
| MIIGJjCCBQ6gAwIBAgITVAAAAANDveocXlnSDQAAAAAAAzANBgkqhkiG9w0BAQsF
| ADBGMRMwEQYKCZImiZPyLGQBGRYDaHRiMRYwFAYKCZImiZPyLGQBGRYGc2VxdWVs
| MRcwFQYDVQQDEw5zZXF1ZWwtREMwMS1DQTAeFw0yNDA2MDgxNzM1MDBaFw0yNTA2
| MDgxNzM1MDBaMBoxGDAWBgNVBAMTD0RDMDEuc2VxdWVsLmh0YjCCASIwDQYJKoZI
| hvcNAQEBBQADggEPADCCAQoCggEBANRCnm8pZ86LZP3kAtl29rFgY5gEOEXSCZSm
| F6Ai+1vh6a8LrCRKMWtC8+Kla0PXgjTcGcmDawcI8h0BsaSH6sQVAD21ca5MQcv0
| xf+4TzrvAnp9H+pVHO1r42cLXBwq14Ak8dSueiOLgxoLKO1CDtKk+e8ZxQWf94Bp
| Vu8rnpImFT6IeDgACeBfb0hLzK2JJRT9ezZiUVxoTfMKKuy4IPFWcshW/1bQfEK0
| ExOcQZVaoCJzRPBUVTp/XGHEW9d6abW8h1UR+64qVfGexsrUKBfxKRsHuHTxa4ts
| +qUVJRbJkzlSgyKGMjhNfT3BPVwwP8HvErWvbsWKKPRkvMaPhU0CAwEAAaOCAzcw
| ggMzMC8GCSsGAQQBgjcUAgQiHiAARABvAG0AYQBpAG4AQwBvAG4AdAByAG8AbABs
| AGUAcjAdBgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwEwDgYDVR0PAQH/BAQD
| AgWgMHgGCSqGSIb3DQEJDwRrMGkwDgYIKoZIhvcNAwICAgCAMA4GCCqGSIb3DQME
| AgIAgDALBglghkgBZQMEASowCwYJYIZIAWUDBAEtMAsGCWCGSAFlAwQBAjALBglg
| hkgBZQMEAQUwBwYFKw4DAgcwCgYIKoZIhvcNAwcwHQYDVR0OBBYEFNfVXsrpSahW
| xfdL4wxFDgtUztvRMB8GA1UdIwQYMBaAFMZBubbkDkfWBlps8YrGlP0a+7jDMIHI
| BgNVHR8EgcAwgb0wgbqggbeggbSGgbFsZGFwOi8vL0NOPXNlcXVlbC1EQzAxLUNB
| LENOPURDMDEsQ049Q0RQLENOPVB1YmxpYyUyMEtleSUyMFNlcnZpY2VzLENOPVNl
| cnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERDPWh0Yj9jZXJ0aWZp
| Y2F0ZVJldm9jYXRpb25MaXN0P2Jhc2U/b2JqZWN0Q2xhc3M9Y1JMRGlzdHJpYnV0
| aW9uUG9pbnQwgb8GCCsGAQUFBwEBBIGyMIGvMIGsBggrBgEFBQcwAoaBn2xkYXA6
| Ly8vQ049c2VxdWVsLURDMDEtQ0EsQ049QUlBLENOPVB1YmxpYyUyMEtleSUyMFNl
| cnZpY2VzLENOPVNlcnZpY2VzLENOPUNvbmZpZ3VyYXRpb24sREM9c2VxdWVsLERD
| PWh0Yj9jQUNlcnRpZmljYXRlP2Jhc2U/b2JqZWN0Q2xhc3M9Y2VydGlmaWNhdGlv
| bkF1dGhvcml0eTA7BgNVHREENDAyoB8GCSsGAQQBgjcZAaASBBDjAT1NPPfwT4sa
| sNjnBqS3gg9EQzAxLnNlcXVlbC5odGIwTQYJKwYBBAGCNxkCBEAwPqA8BgorBgEE
| AYI3GQIBoC4ELFMtMS01LTIxLTU0ODY3MDM5Ny05NzI2ODc0ODQtMzQ5NjMzNTM3
| MC0xMDAwMA0GCSqGSIb3DQEBCwUAA4IBAQCBDjlZZbFac6RlhZ2BhLzvWmA1Xcyn
| jZmYF3aOXmmof1yyO/kxk81fStsu3gtZ94KmpkBwmd1QkSJCuT54fTxg17xDtA49
| QF7O4DPsFkeOM2ip8TAf8x5bGwH5tlZvNjllBCgSpCupZlNY8wKYnyKQDNwtWtgL
| UF4SbE9Q6JWA+Re5lPa6AoUr/sRzKxcPsAjK8kgquUA0spoDrxAqkADIRsHgBLGY
| +Wn+DXHctZtv8GcOwrfW5KkbkVykx8DSS2qH4y2+xbC3ZHjsKlVjoddkjEkrHku0
| 2iXZSIqShMXzXmLTW/G+LzqK3U3VTcKo0yUKqmLlKyZXzQ+kYVLqgOOX
|_-----END CERTIFICATE-----
5985/tcp  open  http          syn-ack Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-server-header: Microsoft-HTTPAPI/2.0
|_http-title: Not Found
9389/tcp  open  mc-nmf        syn-ack .NET Message Framing
47001/tcp open  http          syn-ack Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-server-header: Microsoft-HTTPAPI/2.0
|_http-title: Not Found
49664/tcp open  msrpc         syn-ack Microsoft Windows RPC
49665/tcp open  msrpc         syn-ack Microsoft Windows RPC
49666/tcp open  msrpc         syn-ack Microsoft Windows RPC
49667/tcp open  msrpc         syn-ack Microsoft Windows RPC
49685/tcp open  ncacn_http    syn-ack Microsoft Windows RPC over HTTP 1.0
49686/tcp open  msrpc         syn-ack Microsoft Windows RPC
49689/tcp open  msrpc         syn-ack Microsoft Windows RPC
49694/tcp open  msrpc         syn-ack Microsoft Windows RPC
49716/tcp open  msrpc         syn-ack Microsoft Windows RPC
49739/tcp open  msrpc         syn-ack Microsoft Windows RPC
49809/tcp open  msrpc         syn-ack Microsoft Windows RPC
Service Info: Host: DC01; OS: Windows; CPE: cpe:/o:microsoft:windows
 
Host script results:
| smb2-security-mode:
|   311:
|_    Message signing enabled and required
|_clock-skew: mean: 1m16s, deviation: 0s, median: 1m16s
| p2p-conficker:
|   Checking for Conficker.C or higher...
|   Check 1 (port 62012/tcp): CLEAN (Timeout)
|   Check 2 (port 54223/tcp): CLEAN (Timeout)
|   Check 3 (port 49465/udp): CLEAN (Timeout)
|   Check 4 (port 20179/udp): CLEAN (Timeout)
|_  0/4 checks are positive: Host is CLEAN or ports are blocked
| smb2-time:
|   date: 2025-01-19T12:39:38
|_  start_date: N/A
 
Nmap done: 1 IP address (1 host up) scanned in 102.00 seconds
 
List of open ports: 53,88,135,139,389,445,464,593,636,1433,3268,3269,5985,9389,47001,49664,49665,49666,49667,49685,49686,49689,49694,49716,49739,49809

Looks like a domain controller. Domain name is sequel.htb and DC common name is dc01.sequel.htb

We have credentials rose:KxEPkKe6R8su so we will start with an RID bruteforce to get additional usernames.

Also enumerate SMB shares with provided credentials.

We have access to several shares, let's begin with the "Users" folder.

Nothing useful here, move to the next share.

Download the stuff, the file accounts.xlsx contains several passwords, including what seems to be credentials for MSSQL sa account.

USER

We have disclosed what seems to be MSSQL sa account password, let's try it with Impacket.

Once inside first step would be to enable xp_cmdshell

It seems it is correctly enabled, we can issue xp_cmdshell commands now. We will start by disabling character restrictions.

And now we can launch our favorite reverse shell.

A reverse shell for user sql_svc is received on port 1919.

Since there is a database running, next step would be to enumerate the file system for configuration files. In this case we find clear text passwords in the path c:\sql2019\expressadv_enu\sql-configuration.ini

Since we have a usernames list from our previous RID bruteforce, let's spray the password.

With the found credential we can have an Evil-WinRM session.

And collect the user flag.

SYSTEM

Start from the ryan shell and take the opportunity to enumerate the system.

Also it seems AD CS is installed in the host.

Next step will be to perform an AD enumeration with BloodHound CE. Installation and configuration guide for this tool are available in Certified. In that case, we used BloodHound-Python as a remote data collector; however, in this case, since we have a shell in the system, we will use SharpHound local collector for the sake of testing different tools.

We need to use a SharpHound CE version developed for BloodHound CE, otherwise the data ingestion will fail. The appropriate version can be downloaded from the application GUI itself in Settings → Download Collectors.

Drop a copy of SharpHoundCE.exe in the host and collect the data.

Bring the ZIP to your BloodHoundCE and have a look at the AD, we see ryan has WriteOwner over the user ca_svc. If you click on the edge, the application itself tells how to abuse this.

Essentially, it is the same as did in Certified: first we take ownership of the group, then abuse our position to grant ourselves full control, and finally perform a shadow credential attack to get the victim's NT hash.

Let's begin by taking ownership of the group.

Then abuse the ownership to grant ourselves full control by editing the DACL.

Now we are in a position to perform a shadow credential attack and dump ca_svc user NT hash.

In summary, having full control over an account allows to modify the account's msDS-KeyCredentialLink LDAP attribute. This attribute usually stores public key credentials associated with an AD user or computer object. In this case we will store an alternate credential in the form of a certificate. Later, we will use this certificate to request a TGT on behalf of the user or to dump the NT hash.

This can be done with pyWhisker and PKINITtools (see Certified), or with Certipy, which provides an option to automate a shadow credentials attack in a single command and dump the hash.

We cannot use this hash to have a WinRM shell as ca_svc, but we can use it to remotely find vulnerable templates with Certipy.

There is a template vulnerable to ESC4, which basically means there are users with excessive permissions (i.e. full control) over the template. In other words, SEQUEL.HTB\Cert Publishers can do whatever they want with the template, including modifying it to make it vulnerable to ESC1.

The certificate template is now vulnerable to the ESC1 technique.

We can request a certificate based on the template and specify an arbitrary SAN with either the -upn or -dns parameters.

An with this certificate dump the administrator's NT hash.

The only thing that's left is to open a shell with the hash.

You are root.

REFERENCES

https://i-tracing.com/blog/dacl-shadow-credentials/

https://specterops.io/wp-content/uploads/sites/3/2022/06/Certified_Pre-Owned.pdf

https://github.com/ly4k/Certipy?tab=readme-ov-file#esc4

PreviousSeason 7NextWeek 2. Backfire

Last updated