Detection: Windows PuTTY Suite Utility Execution

Description

This analytic detects the execution of programs associated with the PuTTY SSH client suite, including putty.exe, pscp.exe, plink.exe, psftp.exe, and puttygen.exe. This activity is significant because these tools can be used to establish unauthorized remote connections, transfer files, or execute commands on remote systems. If identified in an unusual context, such as non-administrative accounts or unexpected systems, it may indicate attempts to bypass security controls, perform lateral movement, or exfiltrate data, which could lead to further network compromise.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Processes where
 7
 8(
 9    Processes.process_name IN (
10        "putty.exe",
11        "pscp.exe",
12        "plink.exe",
13        "psftp.exe",
14        "puttygen.exe"
15    )
16    OR
17    Processes.original_file_name IN (
18        "PuTTY",
19        "PSCP",
20        "Plink",
21        "PSFTP",
22        "PuTTYgen"
23    )
24)
25
26by Processes.process Processes.vendor_product Processes.user_id
27   Processes.process_hash Processes.parent_process_name
28   Processes.parent_process_exec Processes.action Processes.dest
29   Processes.process_current_directory Processes.process_path
30   Processes.process_integrity_level Processes.original_file_name
31   Processes.parent_process Processes.parent_process_path
32   Processes.parent_process_guid Processes.parent_process_id
33   Processes.process_guid Processes.process_id
34   Processes.user Processes.process_name
35
36
37| `drop_dm_object_name(Processes)`
38
39| `security_content_ctime(firstTime)`
40
41| `security_content_ctime(lastTime)`
42
43| `windows_putty_suite_utility_execution_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	Other	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'XmlWinEventLog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Some legitimate users may run PuTTY for remote administration or secure file transfers. Filter alerts to exclude approved administrative activities.

Associated Analytic Story

• Active Directory Lateral Movement

• Command And Control

Risk Based Analytics (RBA)

Risk Message:

Potential PuTTY suite activity observed on $dest$ via $process$.

Detection Testing

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1