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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Proxy Port Activity to the Internet

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Proxy Port Activity to the Internet

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Detects events that may describe network events of proxy use to the Internet. It includes popular HTTP proxy ports and SOCKS proxy ports. Typically, environments will use an internal IP address for a proxy server. It can also be used to circumvent network controls and detection mechanisms.

Rule type: query

Rule indices:

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

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

Tags:

Elastic
Host
Network
Threat Detection
Command and Control

Version: 8 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 7.12.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Some proxied applications may use these ports but this usually occurs in local traffic using private IPs which this rule does not match. Proxies are widely used as a security technology but in enterprise environments this is usually local traffic which this rule does not match. If desired, internet proxy services using these ports can be added to allowlists. Some screen recording applications may use these ports.

Proxy port activity involving an unusual source or destination may be more suspicious. Some cloud environments may use this port when VPNs or direct connects are not in use and cloud instances are accessed across the Internet. Because these ports are in the ephemeral range, this rule may false under certain conditions such as when a NATed web server replies to a client which has used a port in the range by coincidence. In this case, such servers can be excluded if desired.

Rule query

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event.category:(network or network_traffic) and network.transport:tcp
and (destination.port:(1080 or 3128 or 8080) or
event.dataset:zeek.socks) 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: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/

Rule version history

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Version 8 (7.12.0 release)

Formatting only

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:(1080 or 3128 or 8080) or
event.dataset:zeek.socks) 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:(1080 or 3128 or 8080) 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: (3128 or 8080 or 1080)
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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