[Detection Rules] Adding Documents for v8.12.8 Pre-Built Detection Rules

docs/detections/prebuilt-rules/downloadable-packages/8-12-8/prebuilt-rule-8-12-8-account-discovery-command-via-system-account.asciidoc

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+[[prebuilt-rule-8-12-8-account-discovery-command-via-system-account]]
+=== Account Discovery Command via SYSTEM Account
+
+Identifies when the SYSTEM account uses an account discovery utility. This could be a sign of discovery activity after an adversary has achieved privilege escalation.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* winlogbeat-*
+* logs-endpoint.events.process-*
+* logs-windows.sysmon_operational-*
+
+*Severity*: low
+
+*Risk score*: 21
+
+*Runs every*: 5m
+
+*Searches indices from*: now-9m ({ref}/common-options.html#date-math[Date Math format], see also <<rule-schedule, `Additional look-back time`>>)
+
+*Maximum alerts per execution*: 100
+
+*References*: None
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: Windows
+* Use Case: Threat Detection
+* Tactic: Discovery
+* Tactic: Privilege Escalation
+* Resources: Investigation Guide
+* Data Source: Elastic Defend
+* Data Source: Sysmon
+
+*Version*: 111
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Investigation guide
+
+
+
+*Triage and analysis*
+
+
+
+*Investigating Account Discovery Command via SYSTEM Account*
+
+
+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 account discovery utilities using the SYSTEM account, which is commonly observed after attackers successfully perform privilege escalation or exploit web applications.
+
+
+*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.
+  - If the process tree includes a web-application server process such as w3wp, httpd.exe, nginx.exe and alike, investigate any suspicious file creation or modification in the last 48 hours to assess the presence of any potential webshell backdoor.
+- Investigate other alerts associated with the user/host during the past 48 hours.
+- Determine how the SYSTEM account is being used. For example, users with administrator privileges can spawn a system shell using Windows services, scheduled tasks or other third party utilities.
+
+
+*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).
+- Use the data collected through the analysis to investigate other machines affected in the environment.
+
+
+==== Setup
+
+
+
+*Setup*
+
+
+If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
+events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
+Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
+`event.ingested` to @timestamp.
+For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
+
+
+==== Rule query
+
+
+[source, js]
+----------------------------------
+process where host.os.type == "windows" and event.type == "start" and
+  (?process.Ext.token.integrity_level_name : "System" or
+  ?winlog.event_data.IntegrityLevel : "System") and
+  (
+    process.name : "whoami.exe" or
+    (
+      process.name : "net1.exe" and not process.parent.name : "net.exe" and not process.args : ("start", "stop", "/active:*")
+    )
+  )
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Discovery
+** ID: TA0007
+** Reference URL: https://attack.mitre.org/tactics/TA0007/
+* Technique:
+** Name: System Owner/User Discovery
+** ID: T1033
+** Reference URL: https://attack.mitre.org/techniques/T1033/
+* Tactic:
+** Name: Privilege Escalation
+** ID: TA0004
+** Reference URL: https://attack.mitre.org/tactics/TA0004/
+* Technique:
+** Name: Valid Accounts
+** ID: T1078
+** Reference URL: https://attack.mitre.org/techniques/T1078/
+* Sub-technique:
+** Name: Local Accounts
+** ID: T1078.003
+** Reference URL: https://attack.mitre.org/techniques/T1078/003/

docs/detections/prebuilt-rules/downloadable-packages/8-12-8/prebuilt-rule-8-12-8-adding-hidden-file-attribute-via-attrib.asciidoc

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+[[prebuilt-rule-8-12-8-adding-hidden-file-attribute-via-attrib]]
+=== Adding Hidden File Attribute via Attrib
+
+Adversaries can add the 'hidden' attribute to files to hide them from the user in an attempt to evade detection.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* winlogbeat-*
+* logs-endpoint.events.process-*
+* logs-windows.*
+* endgame-*
+* logs-system.security*
+
+*Severity*: low
+
+*Risk score*: 21
+
+*Runs every*: 5m
+
+*Searches indices from*: now-9m ({ref}/common-options.html#date-math[Date Math format], see also <<rule-schedule, `Additional look-back time`>>)
+
+*Maximum alerts per execution*: 100
+
+*References*: None
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: Windows
+* Use Case: Threat Detection
+* Tactic: Defense Evasion
+* Tactic: Persistence
+* Data Source: Elastic Endgame
+* Resources: Investigation Guide
+* Data Source: Elastic Defend
+
+*Version*: 111
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Investigation guide
+
+
+
+*Triage and analysis*
+
+
+
+*Investigating Adding Hidden File Attribute via Attrib*
+
+
+The `Hidden` attribute is a file or folder attribute that makes the file or folder invisible to regular directory listings when the attribute is set. 
+
+Attackers can use this attribute to conceal tooling and malware to prevent administrators and users from finding it, even if they are looking specifically for it.
+
+This rule looks for the execution of the `attrib.exe` utility with a command line that indicates the modification of the `Hidden` attribute.
+
+> **Note**:
+> This investigation guide uses the https://www.elastic.co/guide/en/security/master/invest-guide-run-osquery.html[Osquery Markdown Plugin] introduced in Elastic Stack version 8.5.0. Older Elastic Stack versions will display unrendered Markdown in this guide.
+
+
+*Possible investigation steps*
+
+
+- Identify the user account that performed the action and whether it should perform this kind of action.
+- Contact the account owner and confirm whether they are aware of this activity.
+- 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.
+- Investigate other alerts associated with the user/host during the past 48 hours.
+- Examine the command line to identify the target file or folder.
+  - Examine the file, which process created it, header, etc.
+  - If suspicious, retrieve the files' SHA-256 hash values using the PowerShell `Get-FileHash` cmdlet and search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
+- Examine the host for derived artifacts that indicate suspicious activities:
+  - Observe and collect information about the following activities in the alert subject host:
+    - Attempts to contact external domains and addresses.
+      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
+      - Examine the DNS cache for suspicious or anomalous entries.
+        - !{osquery{"label":"Osquery - Retrieve DNS Cache","query":"SELECT * FROM dns_cache"}}
+    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
+    - Examine the host services for suspicious or anomalous entries.
+      - !{osquery{"label":"Osquery - Retrieve All Services","query":"SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services"}}
+      - !{osquery{"label":"Osquery - Retrieve Services Running on User Accounts","query":"SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services WHERE\nNOT (user_account LIKE '%LocalSystem' OR user_account LIKE '%LocalService' OR user_account LIKE '%NetworkService' OR\nuser_account == null)\n"}}
+      - !{osquery{"label":"Osquery - Retrieve Service Unsigned Executables with Virustotal Link","query":"SELECT concat('https://www.virustotal.com/gui/file/', sha1) AS VtLink, name, description, start_type, status, pid,\nservices.path FROM services JOIN authenticode ON services.path = authenticode.path OR services.module_path =\nauthenticode.path JOIN hash ON services.path = hash.path WHERE authenticode.result != 'trusted'\n"}}
+
+
+*False positive analysis*
+
+
+- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
+
+
+*Response and remediation*
+
+
+- Initiate the incident response process based on the outcome of the triage.
+- Isolate the involved host to prevent further post-compromise behavior.
+- If the triage identified malware, search the environment for additional compromised hosts.
+  - Implement temporary network rules, procedures, and segmentation to contain the malware.
+  - Stop suspicious processes.
+  - Immediately block the identified indicators of compromise (IoCs).
+  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
+- Remove and block malicious artifacts identified during triage.
+- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
+- 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.
+- Determine the initial vector abused by the attacker and take action to prevent reinfection through 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
+
+
+[source, js]
+----------------------------------
+process where host.os.type == "windows" and event.type == "start" and
+  (process.name : "attrib.exe" or ?process.pe.original_file_name == "ATTRIB.EXE") and process.args : "+h" and
+  not (process.parent.name: "cmd.exe" and process.command_line: "attrib  +R +H +S +A *.cui")
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Defense Evasion
+** ID: TA0005
+** Reference URL: https://attack.mitre.org/tactics/TA0005/
+* Technique:
+** Name: Hide Artifacts
+** ID: T1564
+** Reference URL: https://attack.mitre.org/techniques/T1564/
+* Sub-technique:
+** Name: Hidden Files and Directories
+** ID: T1564.001
+** Reference URL: https://attack.mitre.org/techniques/T1564/001/
+* Technique:
+** Name: File and Directory Permissions Modification
+** ID: T1222
+** Reference URL: https://attack.mitre.org/techniques/T1222/
+* Sub-technique:
+** Name: Windows File and Directory Permissions Modification
+** ID: T1222.001
+** Reference URL: https://attack.mitre.org/techniques/T1222/001/
+* Tactic:
+** Name: Persistence
+** ID: TA0003
+** Reference URL: https://attack.mitre.org/tactics/TA0003/