External Remote Service Logon from Public IP

calendar Jan 23, 2023 · attack.initial_access attack.credential_access attack.t1133 attack.t1078 attack.t1110  ·
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Detects successful logon from public IP address via RDP, SMB, etc. This can indicate a publicly-exposed RDP or SMB port.

Sigma rule (View on GitHub)

 1title: External Remote Service Logon from Public IP
 2id: 259a9cdf-c4dd-4fa2-b243-2269e5ab18a2
 3status: experimental
 4description: Detects successful logon from public IP address via RDP, SMB, etc. This can indicate a publicly-exposed RDP or SMB port.
 5references:
 6    - https://www.inversecos.com/2020/04/successful-4624-anonymous-logons-to.html
 7    - https://twitter.com/Purp1eW0lf/status/1616144561965002752
 8author: Micah Babinski, @micahbabinski
 9date: 2023/01/19
10tags:
11    - attack.initial_access
12    - attack.credential_access
13    - attack.t1133
14    - attack.t1078
15    - attack.t1110
16logsource:
17    product: windows
18    service: security
19detection:
20    selection:
21        EventID: 4624
22        LogonType:
23            - 3 # Network logon such as SMB
24            - 10 # RemoteInteractive logon such as RDP
25    filter_username:
26        SubjectUserName: '-'
27    filter_src_ip:
28        - IpAddress|cidr: 10.0.0.0/8
29        - IpAddress|cidr: 172.16.0.0/12
30        - IpAddress|cidr: 192.168.0.0/16
31        - IpAddress|cidr: 224.0.0.0/4
32        - IpAddress|cidr: 127.0.0.0/8
33    condition: selection and not filter_username and not filter_src_ip
34falsepositives:
35    - Legitimate or intentional inbound connections from public IP addresses on RDP or SMB ports.
36level: medium```

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