ID | Technique | Tactic |
---|---|---|
T1021.001 | Remote Desktop Protocol | Lateral Movement |
T1021 | Remote Services | Lateral Movement |
Detection: Remote Desktop Network Bruteforce
EXPERIMENTAL DETECTION
This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.
Description
The following analytic identifies potential Remote Desktop Protocol (RDP) brute force attacks by monitoring network traffic for RDP application activity. It detects anomalies by filtering source and destination pairs that generate traffic exceeding twice the standard deviation of the average traffic. This method leverages the Network_Traffic data model to identify unusual patterns indicative of brute force attempts. This activity is significant as it may indicate an attacker attempting to gain unauthorized access to systems via RDP. If confirmed malicious, this could lead to unauthorized access, data exfiltration, or further network compromise.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Network_Traffic where All_Traffic.app=rdp by All_Traffic.src All_Traffic.dest All_Traffic.dest_port
3| eventstats stdev(count) AS stdev avg(count) AS avg p50(count) AS p50
4| where count>(avg + stdev*2)
5| rename All_Traffic.src AS src All_Traffic.dest AS dest
6| table firstTime lastTime src dest count avg p50 stdev
7| `remote_desktop_network_bruteforce_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
N/A | N/A | N/A | N/A | N/A |
Macros Used
Name | Value |
---|---|
security_content_summariesonly | summariesonly= summariesonly_config allow_old_summaries= oldsummaries_config fillnull_value= fillnull_config`` |
remote_desktop_network_bruteforce_filter | search * |
remote_desktop_network_bruteforce_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
You must ensure that your network traffic data is populating the Network_Traffic data model.
Known False Positives
RDP gateways may have unusually high amounts of traffic from all other hosts' RDP applications in the network.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
$dest$ may be the target of an RDP Bruteforce | 25 | 50 | 50 |
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | Not Applicable | N/A | N/A | N/A |
Unit | ❌ Failing | N/A | N/A |
N/A |
Integration | ❌ Failing | N/A | N/A |
N/A |
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: 3