Detection rules › Splunk
Rundll32 DNSQuery
The following analytic detects a suspicious rundll32.exe process making HTTP connections and performing DNS queries to web domains. It leverages Sysmon EventCode 22 logs to identify these activities. This behavior is significant as it is commonly associated with IcedID malware, where rundll32.exe checks internet connectivity and communicates with C&C servers to download configurations and other components. If confirmed malicious, this activity could allow attackers to establish persistence, download additional payloads, and exfiltrate sensitive data, posing a severe threat to the network.
Known false positives
- No false positives have been identified at this time.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 22: DNSEvent (DNS query) |
Rule body
name: Rundll32 DNSQuery
id: f1483f5e-ee29-11eb-9d23-acde48001122
version: 13
creation_date: '2021-08-03'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects a suspicious `rundll32.exe` process making HTTP connections and performing DNS queries to web domains. It leverages Sysmon EventCode 22 logs to identify these activities. This behavior is significant as it is commonly associated with IcedID malware, where `rundll32.exe` checks internet connectivity and communicates with C&C servers to download configurations and other components. If confirmed malicious, this activity could allow attackers to establish persistence, download additional payloads, and exfiltrate sensitive data, posing a severe threat to the network.
data_source:
- Sysmon EventID 22
search: |-
`sysmon` EventCode=22 process_name="rundll32.exe"
| stats count min(_time) as firstTime max(_time) as lastTime
BY answer answer_count dvc
process_exec process_guid process_name
query query_count reply_code_id
signature signature_id src
user_id vendor_product QueryName
QueryResults QueryStatus
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `rundll32_dnsquery_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name and eventcode = 22 dnsquery executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where renamed rundll32.exe may be used.
known_false_positives: No false positives have been identified at this time.
references:
- https://any.run/malware-trends/icedid
finding:
title: rundll32 process $process_name$ made a DNS query for $query$ from host $dvc$
entity:
field: dvc
type: system
score: 50
threat_objects:
- field: process_name
type: process_name
analytic_story:
- IcedID
- Living Off The Land
asset_type: Endpoint
mitre_attack_id:
- T1218.011
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: network
security_domain: endpoint
Stages and Predicates
Stage 1: search
`sysmon` EventCode=22 process_name="rundll32.exe"
Stage 2: stats
| stats count min(_time) as firstTime max(_time) as lastTime
BY answer answer_count dvc
process_exec process_guid process_name
query query_count reply_code_id
signature signature_id src
user_id vendor_product QueryName
QueryResults QueryStatus
Stage 3: search
| `security_content_ctime(firstTime)`
Stage 4: search
| `security_content_ctime(lastTime)`
Stage 5: search
| `rundll32_dnsquery_filter`
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"22" |
process_name | eq |
| field:"process_name" kind:eq |