SonicWall - Allowed SSH, Telnet, and RDP Connections

Status: experimental
Severity: medium
Time window: 1h
Source: github.com/Azure/Azure-Sentinel

'This rule identifies allowed inbound SSH, Telnet, and RDP connections. This analytic rule leverages the SonicWall Firewall ASIM Network Session parser (ASimNetworkSessionSonicWallFirewall).'

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1133` External Remote Services, `T1190` Exploit Public-Facing Application
Execution	`T1059` Command and Scripting Interpreter
Persistence	`T1133` External Remote Services
Credential Access	`T1003` OS Credential Dumping, `T1110` Brute Force
Discovery	`T1018` Remote System Discovery, `T1087` Account Discovery
Lateral Movement	`T1021` Remote Services
Collection	`T1005` Data from Local System
Exfiltration	`T1011` Exfiltration Over Other Network Medium, `T1041` Exfiltration Over C2 Channel, `T1048` Exfiltration Over Alternative Protocol, `T1567` Exfiltration Over Web Service
Impact	`T1490` Inhibit System Recovery

Rule body kusto

id: 27f1a570-5f20-496b-88f6-a9aa2c5c9534
name: SonicWall - Allowed SSH, Telnet, and RDP Connections
description: |
  'This rule identifies allowed inbound SSH, Telnet, and RDP connections. This analytic rule leverages the SonicWall Firewall ASIM Network Session parser (ASimNetworkSessionSonicWallFirewall).'
severity: Medium
status: Experimental
requiredDataConnectors:
  - connectorId: CEF
    dataTypes:
      - CommonSecurityLog
  - connectorId: SonicWallFirewall
    dataTypes:
      - ASimNetworkSessionSonicWallFirewall
  - connectorId: CefAma
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - Execution
  - Persistence
  - CredentialAccess
  - Discovery
  - LateralMovement
  - Collection
  - Exfiltration
  - Impact
relevantTechniques:
  - T1190
  - T1133
  - T1059
  - T1133
  - T1110
  - T1003
  - T1087
  - T1018
  - T1021
  - T1005
  - T1048
  - T1041
  - T1011
  - T1567
  - T1490
query: |
  ASimNetworkSessionSonicWallFirewall(false)
  | where NetworkDirection == "Inbound" and EventResult in ("NA", "Success")
  | where EventOriginalType != 1370
  | where SrcAppName contains "Windows Remote Desktop Services"
      or SrcAppName contains "Telnet"
      or (SrcAppName contains "SSH Protocol" and ThreatId != 446) // Filters out SSH server responses.
      or SrcAppName contains "Bitvise SSH"
      or DstPortNumber in (22, 23, 3389)
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SrcIpAddr
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: DstIpAddr
version: 1.0.1
kind: Scheduled

Stages and Predicates

Stage 1: `source`

ASimNetworkSessionSonicWallFirewall(false)

Stage 2: `where`

| where NetworkDirection == "Inbound" and EventResult in ("NA", "Success")

Stage 3: `where`

| where EventOriginalType != 1370

Stage 4: `where`

| where SrcAppName contains "Windows Remote Desktop Services"
    or SrcAppName contains "Telnet"
    or (SrcAppName contains "SSH Protocol" and ThreatId != 446)
    or SrcAppName contains "Bitvise SSH"
    or DstPortNumber in (22, 23, 3389)

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
`DstPortNumber`	in	`22` transforms: `cased` `23` transforms: `cased` `3389` transforms: `cased`
`EventOriginalType`	ne	`1370` transforms: `cased`
`EventResult`	in	`NA` transforms: `cased` `Success` transforms: `cased`
`NetworkDirection`	eq	`Inbound` transforms: `cased`
`SrcAppName`	contains	`Bitvise SSH` `SSH Protocol` `Telnet` `Windows Remote Desktop Services`
`ThreatId`	ne	`446` transforms: `cased`

`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)

SonicWall - Allowed SSH, Telnet, and RDP Connections

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Indicators

Keyboard shortcuts

Search operators

SonicWall - Allowed SSH, Telnet, and RDP Connections

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Indicators

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`