[Detection Rules] Adding Documents for v8.11.20 Pre-Built Detection Rules

docs/detections/prebuilt-rules/downloadable-packages/8-11-20/prebuilt-rule-8-11-20-active-directory-group-modification-by-system.asciidoc

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+[[prebuilt-rule-8-11-20-active-directory-group-modification-by-system]]
+=== Active Directory Group Modification by SYSTEM
+
+Identifies a user being added to an active directory group by the SYSTEM (S-1-5-18) user. This behavior can indicate that the attacker has achieved SYSTEM privileges in a domain controller, which attackers can obtain by exploiting vulnerabilities or abusing default group privileges (e.g., Server Operators), and is attempting to pivot to a domain account.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* winlogbeat-*
+* logs-system.security*
+* logs-windows.forwarded*
+
+*Severity*: medium
+
+*Risk score*: 47
+
+*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: Persistence
+* Use Case: Active Directory Monitoring
+* Data Source: Active Directory
+
+*Version*: 1
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Rule query
+
+
+[source, js]
+----------------------------------
+iam where winlog.api == "wineventlog" and event.code == "4728" and
+winlog.event_data.SubjectUserSid : "S-1-5-18" and
+
+/* DOMAIN_USERS and local groups */
+not group.id : "S-1-5-21-*-513"
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Persistence
+** ID: TA0003
+** Reference URL: https://attack.mitre.org/tactics/TA0003/
+* Technique:
+** Name: Account Manipulation
+** ID: T1098
+** Reference URL: https://attack.mitre.org/techniques/T1098/
+* Tactic:
+** Name: Privilege Escalation
+** ID: TA0004
+** Reference URL: https://attack.mitre.org/tactics/TA0004/
+* Technique:
+** Name: Account Manipulation
+** ID: T1098
+** Reference URL: https://attack.mitre.org/techniques/T1098/

docs/detections/prebuilt-rules/downloadable-packages/8-11-20/prebuilt-rule-8-11-20-bypass-uac-via-event-viewer.asciidoc

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+[[prebuilt-rule-8-11-20-bypass-uac-via-event-viewer]]
+=== Bypass UAC via Event Viewer
+
+Identifies User Account Control (UAC) bypass via eventvwr.exe. Attackers bypass UAC to stealthily execute code with elevated permissions.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* winlogbeat-*
+* logs-endpoint.events.process-*
+* logs-windows.*
+* endgame-*
+* logs-system.security*
+* logs-m365_defender.event-*
+
+*Severity*: high
+
+*Risk score*: 73
+
+*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: Privilege Escalation
+* Tactic: Defense Evasion
+* Resources: Investigation Guide
+* Data Source: Elastic Endgame
+* Data Source: Elastic Defend
+* Data Source: Microsoft Defender for Endpoint
+
+*Version*: 113
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Investigation guide
+
+
+
+*Triage and analysis*
+
+
+
+*Investigating Bypass UAC via Event Viewer*
+
+
+Windows User Account Control (UAC) allows a program to elevate its privileges (tracked as low to high integrity levels) to perform a task under administrator-level permissions, possibly by prompting the user for confirmation. UAC can deny an operation under high-integrity enforcement, or allow the user to perform the action if they are in the local administrators group and enter an administrator password when prompted.
+
+For more information about the UAC and how it works, check the https://docs.microsoft.com/en-us/windows/security/identity-protection/user-account-control/how-user-account-control-works[official Microsoft docs page].
+
+During startup, `eventvwr.exe` checks the registry value of the `HKCU\Software\Classes\mscfile\shell\open\command` registry key for the location of `mmc.exe`, which is used to open the `eventvwr.msc` saved console file. If the location of another binary or script is added to this registry value, it will be executed as a high-integrity process without a UAC prompt being displayed to the user. This rule detects this UAC bypass by monitoring processes spawned by `eventvwr.exe` other than `mmc.exe` and `werfault.exe`.
+
+> **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*
+
+
+- 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.
+- Inspect the host for suspicious or abnormal behavior in the alert timeframe.
+- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
+- Examine the host for derived artifacts that indicate suspicious activities:
+  - Analyze the process executable using a private sandboxed analysis system.
+  - Observe and collect information about the following activities in both the sandbox and 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"}}
+  - 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.
+- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.
+
+
+
+*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).
+
+
+==== 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.parent.name : "eventvwr.exe" and
+  not process.executable :
+            ("?:\\Windows\\SysWOW64\\mmc.exe",
+             "?:\\Windows\\System32\\mmc.exe",
+             "?:\\Windows\\SysWOW64\\WerFault.exe",
+             "?:\\Windows\\System32\\WerFault.exe")
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Privilege Escalation
+** ID: TA0004
+** Reference URL: https://attack.mitre.org/tactics/TA0004/
+* Technique:
+** Name: Abuse Elevation Control Mechanism
+** ID: T1548
+** Reference URL: https://attack.mitre.org/techniques/T1548/
+* Sub-technique:
+** Name: Bypass User Account Control
+** ID: T1548.002
+** Reference URL: https://attack.mitre.org/techniques/T1548/002/
+* Tactic:
+** Name: Defense Evasion
+** ID: TA0005
+** Reference URL: https://attack.mitre.org/tactics/TA0005/
+* Technique:
+** Name: Abuse Elevation Control Mechanism
+** ID: T1548
+** Reference URL: https://attack.mitre.org/techniques/T1548/
+* Sub-technique:
+** Name: Bypass User Account Control
+** ID: T1548.002
+** Reference URL: https://attack.mitre.org/techniques/T1548/002/

docs/detections/prebuilt-rules/downloadable-packages/8-11-20/prebuilt-rule-8-11-20-dnf-package-manager-plugin-file-creation.asciidoc

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+[[prebuilt-rule-8-11-20-dnf-package-manager-plugin-file-creation]]
+=== DNF Package Manager Plugin File Creation
+
+Detects file creation events in the plugin directories for the Yum package manager. In Linux, DNF (Dandified YUM) is a command-line utility used for handling packages on Fedora-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor DNF to gain persistence by injecting malicious code into plugins that DNF runs, thereby ensuring continued unauthorized access or control each time DNF is used for package management.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* logs-endpoint.events.file*
+
+*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*: 
+
+* https://pwnshift.github.io/2020/10/01/persistence.html
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: Linux
+* Use Case: Threat Detection
+* Tactic: Persistence
+* Tactic: Defense Evasion
+* Data Source: Elastic Defend
+
+*Version*: 1
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Setup
+
+
+
+*Setup*
+
+This rule requires data coming in from Elastic Defend.
+
+
+*Elastic Defend Integration Setup*
+
+Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.
+
+
+*Prerequisite Requirements:*
+
+- Fleet is required for Elastic Defend.
+- To configure Fleet Server refer to the https://www.elastic.co/guide/en/fleet/current/fleet-server.html[documentation].
+
+
+*The following steps should be executed in order to add the Elastic Defend integration on a Linux System:*
+
+- Go to the Kibana home page and click "Add integrations".
+- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
+- Click "Add Elastic Defend".
+- Configure the integration name and optionally add a description.
+- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
+- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html[Helper guide].
+- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
+- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
+
+For more details on Elastic Agent configuration settings, refer to the https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html[helper guide].
+- Click "Save and Continue".
+- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
+
+For more details on Elastic Defend refer to the https://www.elastic.co/guide/en/security/current/install-endpoint.html[helper guide].
+
+
+==== Rule query
+
+
+[source, js]
+----------------------------------
+file where host.os.type == "linux" and event.action in ("rename", "creation") and
+file.path : ("/usr/lib/python*/site-packages/dnf-plugins/*", "/etc/dnf/plugins/*") and not (
+  process.executable in (
+    "/bin/dockerd", "/usr/bin/dockerd", "/usr/sbin/dockerd", "/bin/microdnf", "/usr/bin/microdnf", "/bin/rpm",
+    "/usr/bin/rpm", "/bin/snapd", "/usr/bin/snapd", "/bin/yum", "/usr/bin/yum", "/bin/dnf", "/usr/bin/dnf",
+    "/bin/podman", "/usr/bin/podman", "/bin/dnf-automatic", "/usr/bin/dnf-automatic", "/sbin/apk", "/usr/sbin/apk",
+    "/usr/local/sbin/apk", "/bin/podman", "/usr/bin/podman", "/usr/bin/puppet", "/bin/puppet",
+    "/opt/puppetlabs/puppet/bin/puppet", "/usr/bin/chef-client", "/bin/chef-client", "/bin/autossl_check",
+    "/usr/bin/autossl_check", "/proc/self/exe", "/dev/fd/*", "/usr/lib/snapd/snapd", "/usr/local/bin/dockerd",
+    "/usr/libexec/netplan/generate"
+  ) or
+  file.extension in ("swp", "swpx", "swx") or
+  process.executable : (
+    "/nix/store/*", "/var/lib/dpkg/*", "/tmp/vmis.*", "/snap/*", "/dev/fd/*", "/usr/lib/*", "/usr/libexec/*",
+    "/etc/kernel/*"
+  ) or
+  process.executable == null or
+  (process.name == "sed" and file.name : "sed*") or
+  (process.name == "perl" and file.name : "e2scrub_all.tmp*") 
+)
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Persistence
+** ID: TA0003
+** Reference URL: https://attack.mitre.org/tactics/TA0003/
+* Technique:
+** Name: Create or Modify System Process
+** ID: T1543
+** Reference URL: https://attack.mitre.org/techniques/T1543/
+* Technique:
+** Name: Hijack Execution Flow
+** ID: T1574
+** Reference URL: https://attack.mitre.org/techniques/T1574/
+* Tactic:
+** Name: Defense Evasion
+** ID: TA0005
+** Reference URL: https://attack.mitre.org/tactics/TA0005/