OpenSSH server firewall configuration on Windows (command)

Status: experimental
Severity: high
Log source: product windows, category process_creation
Author: mdecrevoisier
Source: github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker configure the Windows firewall to allow incoming connections to perform stealthy lateral movement.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1562.004` Impair Defenses: Disable or Modify System Firewall

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 4688	A new process has been created.

Rule body yaml

title: OpenSSH server firewall configuration on Windows (command)
description: Detects scenarios where an attacker configure the Windows firewall to allow incoming connections to perform stealthy lateral movement.
references:
 - https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0008-Lateral%20Movement/T1021.004-Remote%20Service%20SSH
 - https://winaero.com/enable-openssh-server-windows-10/
 - https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse
 - https://virtualizationreview.com/articles/2020/05/21/ssh-server-on-windows-10.aspx
tags:
- attack.defense_evasion
- attack.t1562.004
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  category: process_creation
detection:
  selection_event:
    EventID: 4688

  selection_netsh_adv: # Command for firewall rule creation (available starting Server 2012 R2)
    CommandLine|contains|all:
      - netsh
      - advfirewall
      - localport=
      - '22'

  selection_netsh: # Command for firewall rule creation (deprecated)
    CommandLine|contains|all:
      - netsh
      - firewall
      - portopening
      - '22'

  condition: selection_event and (selection_netsh_adv or selection_netsh)
falsepositives:
- Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection_event and (selection_netsh_adv or selection_netsh)

Stage 1: `selection_event`

selection_event:
  EventID: 4688

Stage 2: `selection_netsh_adv`

selection_netsh_adv:
  CommandLine|contains|all:
    - netsh
    - advfirewall
    - localport=
    - '22'

Stage 3: `selection_netsh`

selection_netsh:
  CommandLine|contains|all:
    - netsh
    - firewall
    - portopening
    - '22'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`CommandLine`	match	`22` `advfirewall` corpus 7 (sigma 6, kusto 1) `firewall` corpus 13 (sigma 7, splunk 6) `localport=` `netsh` corpus 9 (sigma 9) `portopening` corpus 2 (sigma 2)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

OpenSSH server firewall configuration on Windows (command)

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_event`

Stage 2: `selection_netsh_adv`

Stage 3: `selection_netsh`

Indicators

Keyboard shortcuts

Search operators

OpenSSH server firewall configuration on Windows (command)

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_event

Stage 2: selection_netsh_adv

Stage 3: selection_netsh

Indicators

Stage 0: `condition`

Stage 1: `selection_event`

Stage 2: `selection_netsh_adv`

Stage 3: `selection_netsh`