Communication To Uncommon Destination Ports

Hunt Hypothesis

Detects programs that connect to uncommon destination ports

Detection Rule

Sigma (Original)

title: Communication To Uncommon Destination Ports
id: 6d8c3d20-a5e1-494f-8412-4571d716cf5c
related:
    - id: 4b89abaa-99fe-4232-afdd-8f9aa4d20382
      type: similar
status: test
description: Detects programs that connect to uncommon destination ports
references:
    - https://docs.google.com/spreadsheets/d/17pSTDNpa0sf6pHeRhusvWG6rThciE8CsXTSlDUAZDyo
author: Florian Roth (Nextron Systems)
date: 2017-03-19
modified: 2024-03-12
tags:
    - attack.persistence
    - attack.command-and-control
    - attack.t1571
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Initiated: 'true'
        DestinationPort:
            - 8080
            - 8888
    filter_main_local_ranges:
        DestinationIp|cidr:
            - '127.0.0.0/8'
            - '10.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '::1/128'  # IPv6 loopback
            - 'fe80::/10'  # IPv6 link-local addresses
            - 'fc00::/7'  # IPv6 private addresses
    filter_optional_sys_directories:
        Image|startswith:
            - 'C:\Program Files\'
            - 'C:\Program Files (x86)\'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

KQL (Azure Sentinel)

imNetworkSession
| where (NetworkDirection =~ "true" and (DstPortNumber in~ ("8080", "8888"))) and (not((ipv4_is_in_range(DstIpAddr, "127.0.0.0/8") or ipv4_is_in_range(DstIpAddr, "10.0.0.0/8") or ipv4_is_in_range(DstIpAddr, "172.16.0.0/12") or ipv4_is_in_range(DstIpAddr, "192.168.0.0/16") or ipv4_is_in_range(DstIpAddr, "169.254.0.0/16") or ipv4_is_in_range(DstIpAddr, "::1/128") or ipv4_is_in_range(DstIpAddr, "fe80::/10") or ipv4_is_in_range(DstIpAddr, "fc00::/7")))) and (not(((SrcProcessName startswith "C:\\Program Files\\" or SrcProcessName startswith "C:\\Program Files (x86)\\") or (DstProcessName startswith "C:\\Program Files\\" or DstProcessName startswith "C:\\Program Files (x86)\\"))))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Persistence
• Tactic: Command and Control
• Technique: T1571 — T1571

References

• https://docs.google.com/spreadsheets/d/17pSTDNpa0sf6pHeRhusvWG6rThciE8CsXTSlDUAZDyo
• SigmaHQ Rule