Cisco Umbrella - Crypto Miner User-Agent Detected

Severity: medium
Time window: 15m
Source: github.com/Azure/Azure-Sentinel

'Detects suspicious user agent strings used by crypto miners in proxy logs.'

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	No specific technique

Rule body

id: b619d1f1-7f39-4c7e-bf9e-afbb46457997
name: Cisco Umbrella - Crypto Miner User-Agent Detected
description: |
  'Detects suspicious user agent strings used by crypto miners in proxy logs.'
severity: Medium
requiredDataConnectors:
  - connectorId: CiscoUmbrellaDataConnector
    dataTypes:
      - Cisco_Umbrella_proxy_CL
queryFrequency: 15m
queryPeriod: 15m
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
query: |
  let timeframe = 15m;
  Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(timeframe)
  | where HttpUserAgentOriginal contains "XMRig" or HttpUserAgentOriginal contains "ccminer"
  | extend Message = "Crypto Miner User Agent"
  | project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated,HttpUserAgentOriginal
entityMappings:
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: UrlOriginal
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SrcIpAddr
version: 1.1.2
kind: Scheduled

Stages and Predicates

Stage 0: `let`

let timeframe = 15m;

Stage 1: `source`

Cisco_Umbrella

Stage 2: `where`

| where EventType == "proxylogs"

Stage 3: `where`

| where TimeGenerated > ago(timeframe)

Stage 4: `where`

| where HttpUserAgentOriginal contains "XMRig" or HttpUserAgentOriginal contains "ccminer"

Stage 5: `extend`

| extend Message = "Crypto Miner User Agent"

Stage 6: `project`

| project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated,HttpUserAgentOriginal

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventType`	eq	`proxylogs`	`field:"EventType" kind:eq value:"proxylogs"`
`HttpUserAgentOriginal`	contains	`XMRig` `ccminer`	`field:"HttpUserAgentOriginal" kind:contains`

Output fields

These fields are emitted when the rule matches.

Field	Source
`DstIpAddr`	`project`
`HttpUserAgentOriginal`	`project`
`Message`	`project`
`SrcIpAddr`	`project`
`TimeGenerated`	`project`
`UrlOriginal`	`project`

Cisco Umbrella - Crypto Miner User-Agent Detected

MITRE ATT&CK coverage

Rule body

Stages and Predicates

Stage 0: let

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: extend

Stage 6: project

Indicators

Output fields

Stage 0: `let`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `project`