Detection rules › Splunk
High Process Termination Frequency
The following analytic identifies a high frequency of process termination events on a computer within a short period. It leverages Sysmon EventCode 5 logs to detect instances where 15 or more processes are terminated within a 3-second window. This behavior is significant as it is commonly associated with ransomware attempting to avoid exceptions during file encryption. If confirmed malicious, this activity could indicate an active ransomware attack, potentially leading to widespread file encryption and significant data loss.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Impact | T1486 Data Encrypted for Impact |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 5 | Process terminated |
Rule body splunk
name: High Process Termination Frequency
id: 17cd75b2-8666-11eb-9ab4-acde48001122
version: 14
creation_date: '2021-03-19'
modification_date: '2026-05-13'
author: Teoderick Contreras
status: production
type: Anomaly
description: The following analytic identifies a high frequency of process termination events on a computer within a short period. It leverages Sysmon EventCode 5 logs to detect instances where 15 or more processes are terminated within a 3-second window. This behavior is significant as it is commonly associated with ransomware attempting to avoid exceptions during file encryption. If confirmed malicious, this activity could indicate an active ransomware attack, potentially leading to widespread file encryption and significant data loss.
data_source:
- Sysmon EventID 5
search: |-
`sysmon` EventCode=5
| bin _time span=3s
| stats values(process) as process values(process_exec) as process_exec values(process_guid) as process_guid values(process_id) as process_id values(process_name) as process_name values(process_path) as process_path values(user_id) as user_id min(_time) as firstTime max(_time) as lastTime count
BY _time dest EventCode
ProcessID signature signature_id
vendor_product
| where count >= 15
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `high_process_termination_frequency_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the Image (process full path of terminated process) from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: admin or user tool that can terminate multiple process.
references:
- https://www.mandiant.com/resources/fin11-email-campaigns-precursor-for-ransomware-data-theft
- https://blog.virustotal.com/2020/11/keep-your-friends-close-keep-ransomware.html
drilldown_searches:
- name: View the detection results for - "$dest$"
search: '%original_detection_search% | search dest = "$dest$"'
earliest_offset: $info_min_time$
latest_offset: $info_max_time$
- name: View risk events for the last 7 days for - "$dest$"
search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
earliest_offset: 7d
latest_offset: "0"
intermediate_findings:
entities:
- field: dest
type: system
score: 20
message: High frequency process termination (more than 15 processes within 3s) detected on host $dest$
analytic_story:
- BlackByte Ransomware
- Rhysida Ransomware
- LockBit Ransomware
- Medusa Ransomware
- Crypto Stealer
- Snake Keylogger
- Clop Ransomware
- Termite Ransomware
- Interlock Ransomware
- NailaoLocker Ransomware
- Hellcat Ransomware
asset_type: Endpoint
mitre_attack_id:
- T1486
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/clop/clop_a/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: search
`sysmon` EventCode=5
Stage 2: bucket
| bin _time span=3s
Stage 3: stats
| stats values(process) as process values(process_exec) as process_exec values(process_guid) as process_guid values(process_id) as process_id values(process_name) as process_name values(process_path) as process_path values(user_id) as user_id min(_time) as firstTime max(_time) as lastTime count
BY _time dest EventCode
ProcessID signature signature_id
vendor_product
Stage 4: where
| where count >= 15
Stage 5: search
| `security_content_ctime(firstTime)`
Stage 6: search
| `security_content_ctime(lastTime)`
Stage 7: search
| `high_process_termination_frequency_filter`
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.