SMB (Windows File Sharing) Activity to the Internet

Last updated a year ago on 2025-01-15

Created 6 years ago on 2020-02-18

About

This rule detects network events that may indicate the use of Windows file sharing (also called SMB or CIFS) traffic to the Internet. SMB is commonly used within networks to share files, printers, and other system resources amongst trusted systems. It should almost never be directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector or for data exfiltration.

Tags

Tactic: Initial AccessDomain: EndpointUse Case: Threat DetectionData Source: PAN-OSLanguage: kuery

Severity

high

Risk Score

MITRE ATT&CK™

Initial Access (TA0001)(external, opens in a new tab or window)

↳ Exploit Public-Facing Application (T1190)(external, opens in a new tab or window)

Exfiltration (TA0010)(external, opens in a new tab or window)

↳ Exfiltration Over Alternative Protocol (T1048)(external, opens in a new tab or window)

License

Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type

Query (Kibana Query Language)

Integration Pack

Prebuilt Security Detection Rules

Index Patterns

packetbeat-*auditbeat-*filebeat-*logs-network_traffic.*logs-panw.panos*

Related Integrations

network_traffic(external, opens in a new tab or window)

panw(external, opens in a new tab or window)

Query

✄𐘗text code block:
✄𐘗(event.dataset: network_traffic.flow or (event.category: (network or network_traffic))) and
  network.transport:tcp and (destination.port:(139 or 445) or event.dataset:zeek.smb) and
  source.ip:(
    10.0.0.0/8 or
    172.16.0.0/12 or
    192.168.0.0/16
  ) and
  not destination.ip:(
    10.0.0.0/8 or
    127.0.0.0/8 or
    169.254.0.0/16 or
    172.16.0.0/12 or
    192.0.0.0/24 or
    192.0.0.0/29 or
    192.0.0.8/32 or
    192.0.0.9/32 or
    192.0.0.10/32 or
    192.0.0.170/32 or
    192.0.0.171/32 or
    192.0.2.0/24 or
    192.31.196.0/24 or
    192.52.193.0/24 or
    192.168.0.0/16 or
    192.88.99.0/24 or
    224.0.0.0/4 or
    100.64.0.0/10 or
    192.175.48.0/24 or
    198.18.0.0/15 or
    198.51.100.0/24 or
    203.0.113.0/24 or
    240.0.0.0/4 or
    "::1" or
    "FE80::/10" or
    "FF00::/8"
  )

Install detection rules in Elastic Security

Detect SMB (Windows File Sharing) Activity to the Internet in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).