IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

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SMB (Windows File Sharing) Activity to the Internet

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SMB (Windows File Sharing) Activity to the Internet

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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 back- door vector or for data exfiltration.

Rule type: query

Rule indices:

filebeat-*
packetbeat-*
logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

Tags:

Elastic
Host
Network
Threat Detection
Initial Access

Version: 7 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 7.11.2

Rule authors: Elastic

Rule license: Elastic License

Rule query

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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 192.168.0.0/16 or 224.0.0.0/4 or "::1" or "FE80::/10"
or "FF00::/8" )

Threat mapping

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Framework: MITRE ATT&CK^TM

Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
Technique:
- Name: Exploit Public-Facing Application
- ID: T1190
- Reference URL: https://attack.mitre.org/techniques/T1190/
Tactic:
- Name: Exfiltration
- ID: TA0010
- Reference URL: https://attack.mitre.org/tactics/TA0010/
Technique:
- Name: Exfiltration Over Alternative Protocol
- ID: T1048
- Reference URL: https://attack.mitre.org/techniques/T1048/

Rule version history

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Version 7 (7.11.2 release)

Formatting only

Version 6 (7.11.0 release)

Updated query, changed from:

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 172.16.0.0/12 or
192.168.0.0/16 or "::1")

Version 5 (7.10.0 release)

Formatting only

Version 4 (7.9.0 release)

Updated query, changed from:

network.transport:tcp and destination.port:(139 or 445) 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 172.16.0.0/12 or
192.168.0.0/16 or "::1")

Version 3 (7.7.0 release)

Updated query, changed from:

network.transport: tcp and destination.port: (139 or 445) and (
network.direction: outbound or ( 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 172.16.0.0/12 or 192.168.0.0/16) ) )

Version 2 (7.6.1 release)

Removed auditbeat-*, packetbeat-*, and winlogbeat-* from the rule indices.

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