Detection rules › Splunk

Rundll32 DNSQuery

Author
Teoderick Contreras, Splunk
Source
upstream

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.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1218.011 System Binary Proxy Execution: Rundll32

Event coverage

ProviderEvent IDTitle
Sysmon22DNSEvent (DNS query)

Stages and Predicates

Stage 1: search

search EventCode=22 process_name="rundll32.exe"

Stage 2: stats

stats 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

search

Stage 4: search

search

Stage 5: search

search `macro`

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.

FieldKindValues
EventCodeeq
  • 22 corpus 15 (splunk 15)
process_nameeq
  • "rundll32.exe"