Analytics Story: Netsh Abuse

Date: 2017-01-05 ID: 2b1800dd-92f9-47ec-a981-fdf1351e5f65 Author: Bhavin Patel, Splunk Product: Splunk Enterprise Security

Description

Detect activities and various techniques associated with the abuse of netsh.exe, which can disable local firewall settings or set up a remote connection to a host from an infected system.

Why it matters

It is a common practice for attackers of all types to leverage native Windows tools and functionality to execute commands for malicious reasons. One such tool on Windows OS is netsh.exe,a command-line scripting utility that allows you to--either locally or remotely--display or modify the network configuration of a computer that is currently running. Netsh.exe can be used to discover and disable local firewall settings. It can also be used to set up a remote connection to a host from an infected system. To get started, run the detection search to identify parent processes of netsh.exe.

Correlation Search

1| tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime sum(All_Risk.calculated_risk_score) as risk_score, count(All_Risk.calculated_risk_score) as risk_event_count, values(All_Risk.annotations.mitre_attack.mitre_tactic_id) as annotations.mitre_attack.mitre_tactic_id, dc(All_Risk.annotations.mitre_attack.mitre_tactic_id) as mitre_tactic_id_count, values(All_Risk.annotations.mitre_attack.mitre_technique_id) as annotations.mitre_attack.mitre_technique_id, dc(All_Risk.annotations.mitre_attack.mitre_technique_id) as mitre_technique_id_count, values(All_Risk.tag) as tag, values(source) as source, dc(source) as source_count from datamodel=Risk.All_Risk where source IN ("*Windows Cmdline Tool Execution From Non-Shell Process*", "*Windows System Network Config Discovery Display DNS*", "*Local Account Discovery With Wmic*", "*Windows Group Discovery Via Net*", "*Windows Create Local Administrator Account Via Net*", "*Windows User Discovery Via Net*", "*Icacls Deny Command*", "*ICACLS Grant Command*", "*Windows Proxy Via Netsh*", "*Processes launching netsh*", "*Disabling Firewall with Netsh*", "*Windows System Network Connections Discovery Netsh*", "*Network Connection Discovery With Arp*", "*Windows System Discovery Using ldap Nslookup*", "*Windows System Shutdown CommandLine*") by All_Risk.risk_object All_Risk.risk_object_type All_Risk.annotations.mitre_attack.mitre_tactic | `drop_dm_object_name(All_Risk)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | where source_count >= 4 | `windows_common_abused_cmd_shell_risk_behavior_filter`

Detections

Name ▲▼	Technique ▲▼	Type ▲▼
Processes launching netsh	Disable or Modify System Firewall	Anomaly

Data Sources

Name ▲▼	Platform ▲▼	Sourcetype ▲▼	Source ▲▼
CrowdStrike ProcessRollup2	N/A	`crowdstrike:events:sensor`	`crowdstrike`
Sysmon EventID 1	Windows	`xmlwineventlog`	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`
Windows Event Log Security 4688	Windows	`xmlwineventlog`	`XmlWinEventLog:Security`

References

Source: GitHub | Version: 1