IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Windows Network Enumeration
editWindows Network Enumeration
editIdentifies attempts to enumerate hosts in a network using the built-in Windows net.exe tool.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- winlogbeat-*
- logs-windows.*
Severity: medium
Risk score: 47
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Discovery
Version: 8 (version history)
Added (Elastic Stack release): 7.11.0
Last modified (Elastic Stack release): 8.4.0
Rule authors: Elastic
Rule license: Elastic License v2
Investigation guide
edit## Triage and analysis ### Investigating Windows Network Enumeration After successfully compromising an environment, attackers may try to gain situational awareness to plan their next steps. This can happen by running commands to enumerate network resources, users, connections, files, and installed security software. This rule looks for the execution of the `net` utility to enumerate servers in the environment that hosts shared drives or printers. This information is useful to attackers as they can identify targets for lateral movements and search for valuable shared data. #### Possible investigation steps - Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures. - Identify the user account that performed the action and whether it should perform this kind of action. - Investigate other alerts associated with the user/host during the past 48 hours. - Investigate abnormal behaviors observed using the account, such as commands executed, files created or modified, and network connections. ### False positive analysis - Discovery activities are not inherently malicious if they occur in isolation. As long as the analyst did not identify suspicious activity related to the user or host, such alerts can be dismissed. ### Response and remediation - Initiate the incident response process based on the outcome of the triage. - Isolate the involved hosts to prevent further post-compromise behavior. - Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business systems, and web services. - Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components. - Determine the initial vector abused by the attacker and take action to prevent reinfection via the same vector. - Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the mean time to respond (MTTR).
Rule query
editprocess where event.type in ("start", "process_started") and ((process.name : "net.exe" or process.pe.original_file_name == "net.exe") or ((process.name : "net1.exe" or process.pe.original_file_name == "net1.exe") and not process.parent.name : "net.exe")) and (process.args : "view" or (process.args : "time" and process.args : "\\\\*")) /* expand when ancestry is available and not descendant of [process where event.type == ("start", "process_started") and process.name : "cmd.exe" and ((process.parent.name : "userinit.exe") or (process.parent.name : "gpscript.exe") or (process.parent.name : "explorer.exe" and process.args : "C:\\*\\Start Menu\\Programs\\Startup\\*.bat*"))] */
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Discovery
- ID: TA0007
- Reference URL: https://attack.mitre.org/tactics/TA0007/
-
Technique:
- Name: Remote System Discovery
- ID: T1018
- Reference URL: https://attack.mitre.org/techniques/T1018/
Rule version history
edit- Version 8 (8.4.0 release)
-
- Formatting only
- Version 6 (8.3.0 release)
-
- Formatting only
- Version 5 (8.2.0 release)
-
- Formatting only
- Version 4 (7.15.0 release)
-
-
Updated query, changed from:
process where event.type in ("start", "process_started") and ((process.name : "net.exe" or process.pe.original_file_name == "net.exe") or ((process.name : "net1.exe" or process.pe.original_file_name == "net1.exe") and not process.parent.name : "net.exe")) and (process.args : "view" or (process.args : "time" and process.args : "\\\\*")) /* expand when ancestory is available and not descendant of [process where event.type == ("start", "process_started") and process.name : "cmd.exe" and ((process.parent.name : "userinit.exe") or (process.parent.name : "gpscript.exe") or (process.parent.name : "explorer.exe" and process.args : "C:\\*\\Start Menu\\Programs\\Startup\\*.bat*"))] */
-
- Version 3 (7.12.0 release)
-
- Formatting only
- Version 2 (7.11.2 release)
-
- Formatting only