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splunk-security_content/detections/endpoint/possible_browser_pass_view_parameter.yml
2023-09-15 10:58:38 -07:00

85 lines
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YAML

name: Possible Browser Pass View Parameter
id: 8ba484e8-4b97-11ec-b19a-acde48001122
version: 1
date: '2021-11-22'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
description: This analytic will detect if a suspicious process contains a commandline
parameter related to a web browser credential dumper. This technique is used by
Remcos RAT malware which uses the Nirsoft webbrowserpassview.exe application to
dump web browser credentials. Remcos uses the "/stext" command line to dump the
credentials in text format. This Hunting query is a good indicator of hosts suffering
from possible Remcos RAT infection. Since the hunting query is based on the parameter
command and the possible path where it will save the text credential information,
it may catch normal tools that are using the same command and behavior.
data_source:
- Sysmon Event ID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.process IN ("*/stext
*", "*/shtml *", "*/LoadPasswordsIE*", "*/LoadPasswordsFirefox*", "*/LoadPasswordsChrome*",
"*/LoadPasswordsOpera*", "*/LoadPasswordsSafari*" , "*/UseOperaPasswordFile*", "*/OperaPasswordFile*","*/stab*",
"*/scomma*", "*/stabular*", "*/shtml*", "*/sverhtml*", "*/sxml*", "*/skeepass*"
) AND Processes.process IN ("*\\temp\\*", "*\\users\\public\\*", "*\\programdata\\*")
by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process
Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
Processes.original_file_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` | `possible_browser_pass_view_parameter_filter`'
how_to_implement: 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: False positive is quite limited. Filter is needed
references:
- https://www.nirsoft.net/utils/web_browser_password.html
- https://app.any.run/tasks/df0baf9f-8baf-4c32-a452-16562ecb19be/
tags:
analytic_story:
- Remcos
asset_type: Endpoint
confidence: 40
impact: 40
message: suspicious process $process_name$ contains commandline $process$ on $dest$
mitre_attack_id:
- T1555.003
- T1555
observable:
- name: user
type: User
role:
- Victim
- name: dest
type: Hostname
role:
- Victim
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.parent_process
- Processes.original_file_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
- Processes.parent_process_id
risk_score: 16
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1555/web_browser_pass_view/sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: xmlwineventlog