Azure Network Security Configuration Modified or Deleted

Status: Experimental
Severity: medium
Log types: Azure.MonitorActivity
Tags: AZT506, Defense Evasion, Impact, Impair Defenses, Disable or Modify Cloud Firewall, Data Destruction
Reference: https://attack.mitre.org/techniques/T1562/007/
Source: github.com/panther-labs/panther-analysis

Identifies when a network security configuration is modified or deleted. This includes Network Security Group (NSG) changes, security rule modifications, NSG joins to subnets/interfaces, and diagnostic settings changes. These actions may indicate defense evasion, persistence, or preparation for data exfiltration.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1562.007` Impair Defenses: Disable or Modify Cloud Firewall
Impact	`T1485` Data Destruction

Rule body yaml

AnalysisType: rule
Filename: azure_nsg_deleted_or_modified.py
RuleID: "Azure.MonitorActivity.Network.NSGModifiedOrDeleted"
DisplayName: "Azure Network Security Configuration Modified or Deleted"
Enabled: true
LogTypes:
  - Azure.MonitorActivity
Severity: Medium
Status: Experimental
Description: >
  Identifies when a network security configuration is modified or deleted.
  This includes Network Security Group (NSG) changes, security rule modifications, NSG joins to subnets/interfaces,
  and diagnostic settings changes. These actions may indicate defense evasion, persistence, or preparation for data exfiltration.
Reports:
  MITRE ATT&CK:
    - TA0005:T1562.007 # Defense Evasion: Impair Defenses - Disable or Modify Cloud Firewall
    - TA0040:T1485 # Impact: Data Destruction
Tags:
  - AZT506
  - Defense Evasion
  - Impact
  - Impair Defenses
  - Disable or Modify Cloud Firewall
  - Data Destruction
Runbook: |
  1. Find all network security group and firewall operations by the callerIpAddress in the 24 hours before and after this alert to identify if multiple security controls are being modified
  2. Query for all network configuration changes from the same caller in the past 7 days to determine if this is part of a broader defense evasion pattern
  3. Check if the callerIpAddress is associated with known VPNs or corporate network ranges used by authorized network administrators
Reference: https://attack.mitre.org/techniques/T1562/007/
SummaryAttributes:
  - resourceId
  - callerIpAddress
  - correlationId
Tests:
  - Name: NSG Deleted Successfully
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T10:30:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg",
        "operationName": "Microsoft.Network/networkSecurityGroups/delete",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "resultSignature": "200",
        "callerIpAddress": "1.1.1.1",
        "correlationId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
        "location": "",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: NSG Modified
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T13:30:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg",
        "operationName": "Microsoft.Network/networkSecurityGroups/write",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "1.2.3.4",
        "correlationId": "d4e5f6a7-b8c9-0123-def0-333333333333",
        "location": "westus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Security Rule Created
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T14:00:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg/securityRules/AllowRDP",
        "operationName": "Microsoft.Network/networkSecurityGroups/securityRules/write",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "4.4.4.4",
        "correlationId": "b2c3d4e5-f6a7-8901-bcde-f01234567890",
        "location": "westus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Security Rule Deleted
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T14:15:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg/securityRules/DenyAll",
        "operationName": "Microsoft.Network/networkSecurityGroups/securityRules/delete",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "3.3.3.3",
        "correlationId": "c3d4e5f6-a7b8-9012-cdef-555555555555",
        "location": "eastus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: NSG Join Action
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T14:30:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg",
        "operationName": "Microsoft.Network/networkSecurityGroups/join/action",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "2.2.2.2",
        "correlationId": "d4e5f6a7-b8c9-0123-def0-444444444444",
        "location": "westus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Diagnostic Settings Modified
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T14:45:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg/providers/microsoft.insights/diagnosticSettings/default",
        "operationName": "Microsoft.Network/networkSecurityGroups/providers/microsoft.insights/diagnosticSettings/write",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "1.1.1.1",
        "correlationId": "e5f6a7b8-c9d0-1234-ef01-333333333333",
        "location": "eastus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Case Insensitive Match
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T11:45:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/prod-rg/providers/Microsoft.Network/networkSecurityGroups/prodnsg",
        "operationName": "microsoft.network/networksecuritygroups/delete",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Succeeded",
        "callerIpAddress": "1.2.3.4",
        "correlationId": "f9e8d7c6-b5a4-3210-9876-fedcba098765",
        "location": "eastus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Different Operation
    ExpectedResult: false
    Log:
      {
        "time": "2024-12-17T15:15:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Network/networkSecurityGroups/mynsg",
        "operationName": "Microsoft.Network/networkSecurityGroups/read",
        "operationVersion": "2021-04-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "25.26.27.28",
        "correlationId": "a7b8c9d0-e1f2-3456-0123-456789012345",
        "location": "eastus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }

Detection logic

Condition

operationName in ["MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/WRITE", "MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/DELETE", "MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/SECURITYRULES/WRITE", "MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/SECURITYRULES/DELETE", "MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/JOIN/ACTION", "MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/PROVIDERS/MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/WRITE"]
resultType in ["Success", "Succeeded"]

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
`operationName`	in	`MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/DELETE` `MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/JOIN/ACTION` `MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/PROVIDERS/MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/WRITE` `MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/SECURITYRULES/DELETE` `MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/SECURITYRULES/WRITE` `MICROSOFT.NETWORK/NETWORKSECURITYGROUPS/WRITE`
`resultType`	in	`Succeeded` `Success`

`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)