Detection rules › Splunk
Impacket atexec.py Scheduled Task Creation (Windows Event Log)
Impacket's atexec.py is a tool designed for executing commands on a target system via the Windows Task Scheduler to run arbitrary commands with the privileges of the account under which the scheduler is running, often providing a method for remote command execution which can be used by attackers during post-exploitation activities. This use case detects the creation of scheduled tasks matching characteristics of those created by Impacket atexec.py, notably the presence of commands in the task content and an 8 character mixed-case alphabetic task name.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1053.005 Scheduled Task/Job: Scheduled Task, T1059.003 Command and Scripting Interpreter: Windows Command Shell |
| Persistence | T1053.005 Scheduled Task/Job: Scheduled Task |
| Privilege Escalation | T1053.005 Scheduled Task/Job: Scheduled Task |
| Stealth | T1027 Obfuscated Files or Information |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4698 | A scheduled task was created. |
Rule body yaml
id: '29247.52789'
title: Impacket atexec.py Scheduled Task Creation
description: Impacket's atexec.py is a tool designed for executing commands on a target
system via the Windows Task Scheduler to run arbitrary commands with the privileges
of the account under which the scheduler is running, often providing a method for
remote command execution which can be used by attackers during post-exploitation
activities. This use case detects the creation of scheduled tasks matching characteristics
of those created by Impacket atexec.py, notably the presence of commands in the
task content and an 8 character mixed-case alphabetic task name.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4698) OR
"<EventID>4698<") "exec" "/C" ".tmp" | where match(TaskName, "^\x5c[A-Za-z]{8}$")
| table _time, host, user, TaskName | bin span=1s | stats values(*) as * by _time,
host '
techniques:
- execution:scheduled task/job
- execution:command and scripting interpreter
- execution:scheduled task/job:scheduled task
- persistence:scheduled task/job:scheduled task
- privilege-escalation:scheduled task/job:scheduled task
- execution:command and scripting interpreter:windows command shell
- defense-evasion:obfuscated files or information
technique_id:
- T1053
- T1059
- T1053.005
- T1059.003
- T1027
data_category:
- Windows event logs
references:
- https://u0041.co/blog/post/1
- https://github.com/fortra/impacket/blob/master/examples/atexec.py
- https://labs.withsecure.com/content/dam/labs/docs/WithSecure-Lazarus-No-Pineapple-Threat-Intelligence-Report-2023.pdf
- https://thedfirreport.com/2023/10/30/netsupport-intrusion-results-in-domain-compromise/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4698) OR "<EventID>4698<") "exec" "/C" ".tmp"
Stage 2: where
| where match(TaskName, "^\x5c[A-Za-z]{8}$")
Stage 3: table
| table _time, host, user, TaskName
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
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.
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>4698<" |
| 1 | "exec" |
| 1 | "/C" |
| 1 | ".tmp" |