[Detection Rules] Adding Documents for v8.9.9 Pre-Built Detection Rules

docs/detections/prebuilt-rules/downloadable-packages/8-9-9/prebuilt-rule-8-9-9-abnormal-process-id-or-lock-file-created.asciidoc

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+[[prebuilt-rule-8-9-9-abnormal-process-id-or-lock-file-created]]
+=== Abnormal Process ID or Lock File Created
+
+Identifies the creation of a Process ID (PID), lock or reboot file created in temporary file storage paradigm (tmpfs) directory /var/run. On Linux, the PID files typically hold the process ID to track previous copies running and manage other tasks. Certain Linux malware use the /var/run directory for holding data, executables and other tasks, disguising itself or these files as legitimate PID files.
+
+*Rule type*: new_terms
+
+*Rule indices*: 
+
+* logs-endpoint.events.*
+
+*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*: 
+
+* https://www.sandflysecurity.com/blog/linux-file-masquerading-and-malicious-pids-sandfly-1-2-6-update/
+* https://twitter.com/GossiTheDog/status/1522964028284411907
+* https://exatrack.com/public/Tricephalic_Hellkeeper.pdf
+* https://www.elastic.co/security-labs/a-peek-behind-the-bpfdoor
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: Linux
+* Use Case: Threat Detection
+* Tactic: Execution
+* Threat: BPFDoor
+* Resources: Investigation Guide
+* Data Source: Elastic Defend
+
+*Version*: 211
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Investigation guide
+
+
+[source, markdown]
+----------------------------------
+## Triage and analysis
+
+### Investigating Abnormal Process ID or Lock File Created
+
+Linux applications may need to save their process identification number (PID) for various purposes: from signaling that a program is running to serving as a signal that a previous instance of an application didn't exit successfully. PID files contain its creator process PID in an integer value.
+
+Linux lock files are used to coordinate operations in files so that conflicts and race conditions are prevented.
+
+This rule identifies the creation of PID, lock, or reboot files in the /var/run/ directory. Attackers can masquerade malware, payloads, staged data for exfiltration, and more as legitimate PID files.
+
+#### Possible investigation steps
+
+- Retrieve the file and determine if it is malicious:
+    - Check the contents of the PID files. They should only contain integer strings.
+    - Check the file type of the lock and PID files to determine if they are executables. This is only observed in     malicious files.
+    - Check the size of the subject file. Legitimate PID files should be under 10 bytes.
+    - Check if the lock or PID file has high entropy. This typically indicates an encrypted payload.
+        - Analysts can use tools like `ent` to measure entropy.
+    - Examine the reputation of the SHA-256 hash in the PID file. Use a database like VirusTotal to identify additional pivots and artifacts for investigation.
+- Trace the file's creation to ensure it came from a legitimate or authorized process.
+- Investigate other alerts associated with the user/host during the past 48 hours.
+- Investigate any abnormal account behavior, such as command executions, file creations or modifications, and network connections.
+- Investigate any abnormal behavior by the subject process such as network connections, file modifications, and any spawned child processes.
+
+### False positive analysis
+
+- False positives can appear if the PID file is legitimate and holding a process ID as intended. If the PID file is an executable or has a file size that's larger than 10 bytes, it should be ruled suspicious.
+- If this activity is expected and noisy in your environment, consider adding exceptions — preferably with a combination of file name and process executable conditions.
+
+### 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.
+- 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.
+- Block the identified indicators of compromise (IoCs).
+- Take actions to terminate processes and connections used by the attacker.
+- 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 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]
+----------------------------------
+host.os.type:linux and event.category:file and event.action:creation and
+user.id:0 and file.extension:(pid or lock or reboot) and file.path:(/var/run/* or /run/*) and (
+  (process.name : (
+    bash or dash or sh or tcsh or csh or zsh or ksh or fish or ash or touch or nano or vim or vi or editor or mv or cp)
+  ) or (
+  process.executable : (
+    ./* or /tmp/* or /var/tmp/* or /dev/shm/* or /var/run/* or /boot/* or /srv/* or /run/*
+  ))
+) and not process.name : (go or git or containerd* or snap-confine)
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Execution
+** ID: TA0002
+** Reference URL: https://attack.mitre.org/tactics/TA0002/
+* Technique:
+** Name: Native API
+** ID: T1106
+** Reference URL: https://attack.mitre.org/techniques/T1106/

docs/detections/prebuilt-rules/downloadable-packages/8-9-9/prebuilt-rule-8-9-9-access-of-stored-browser-credentials.asciidoc

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+[[prebuilt-rule-8-9-9-access-of-stored-browser-credentials]]
+=== Access of Stored Browser Credentials
+
+Identifies the execution of a process with arguments pointing to known browser files that store passwords and cookies. Adversaries may acquire credentials from web browsers by reading files specific to the target browser.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* auditbeat-*
+* logs-endpoint.events.*
+
+*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*: 
+
+* https://securelist.com/calisto-trojan-for-macos/86543/
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: macOS
+* Use Case: Threat Detection
+* Tactic: Credential Access
+* Data Source: Elastic Defend
+
+*Version*: 105
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Rule query
+
+
+[source, js]
+----------------------------------
+process where host.os.type == "macos" and event.type in ("start", "process_started") and
+  process.args :
+    (
+      "/Users/*/Library/Application Support/Google/Chrome/Default/Login Data",
+      "/Users/*/Library/Application Support/Google/Chrome/Default/Cookies",
+      "/Users/*/Library/Application Support/Google/Chrome/Profile*/Cookies",
+      "/Users/*/Library/Cookies*",
+      "/Users/*/Library/Application Support/Firefox/Profiles/*.default/cookies.sqlite",
+      "/Users/*/Library/Application Support/Firefox/Profiles/*.default/key*.db",
+      "/Users/*/Library/Application Support/Firefox/Profiles/*.default/logins.json",
+      "Login Data",
+      "Cookies.binarycookies",
+      "key4.db",
+      "key3.db",
+      "logins.json",
+      "cookies.sqlite"
+    ) and 
+  not (process.name : "wordexp-helper" and process.parent.name : ("elastic-agent", "elastic-endpoint"))
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Credential Access
+** ID: TA0006
+** Reference URL: https://attack.mitre.org/tactics/TA0006/
+* Technique:
+** Name: Steal Web Session Cookie
+** ID: T1539
+** Reference URL: https://attack.mitre.org/techniques/T1539/
+* Technique:
+** Name: Credentials from Password Stores
+** ID: T1555
+** Reference URL: https://attack.mitre.org/techniques/T1555/
+* Sub-technique:
+** Name: Credentials from Web Browsers
+** ID: T1555.003
+** Reference URL: https://attack.mitre.org/techniques/T1555/003/

docs/detections/prebuilt-rules/downloadable-packages/8-9-9/prebuilt-rule-8-9-9-access-to-a-sensitive-ldap-attribute.asciidoc

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+[[prebuilt-rule-8-9-9-access-to-a-sensitive-ldap-attribute]]
+=== Access to a Sensitive LDAP Attribute
+
+Identify access to sensitive Active Directory object attributes that contains credentials and decryption keys such as unixUserPassword, ms-PKI-AccountCredentials and msPKI-CredentialRoamingTokens.
+
+*Rule type*: eql
+
+*Rule indices*: 
+
+* winlogbeat-*
+* logs-system.*
+* logs-windows.*
+
+*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*: 
+
+* https://www.mandiant.com/resources/blog/apt29-windows-credential-roaming
+* https://social.technet.microsoft.com/wiki/contents/articles/11483.windows-credential-roaming.aspx
+* https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-5136
+
+*Tags*: 
+
+* Domain: Endpoint
+* OS: Windows
+* Use Case: Threat Detection
+* Tactic: Credential Access
+* Tactic: Privilege Escalation
+* Use Case: Active Directory Monitoring
+* Data Source: Active Directory
+
+*Version*: 9
+
+*Rule authors*: 
+
+* Elastic
+
+*Rule license*: Elastic License v2
+
+
+==== Rule query
+
+
+[source, js]
+----------------------------------
+any where event.action == "Directory Service Access" and event.code == "4662" and
+
+  not winlog.event_data.SubjectUserSid : "S-1-5-18" and
+
+  winlog.event_data.Properties : (
+   /* unixUserPassword */
+  "*612cb747-c0e8-4f92-9221-fdd5f15b550d*",
+
+  /* ms-PKI-AccountCredentials */
+  "*b8dfa744-31dc-4ef1-ac7c-84baf7ef9da7*",
+
+  /*  ms-PKI-DPAPIMasterKeys */
+  "*b3f93023-9239-4f7c-b99c-6745d87adbc2*",
+
+  /* msPKI-CredentialRoamingTokens */
+  "*b7ff5a38-0818-42b0-8110-d3d154c97f24*"
+  ) and
+
+  /*
+   Excluding noisy AccessMasks
+   0x0 undefined and 0x100 Control Access
+   https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4662
+   */
+  not winlog.event_data.AccessMask in ("0x0", "0x100")
+
+----------------------------------
+
+*Framework*: MITRE ATT&CK^TM^
+
+* Tactic:
+** Name: Credential Access
+** ID: TA0006
+** Reference URL: https://attack.mitre.org/tactics/TA0006/
+* Technique:
+** Name: OS Credential Dumping
+** ID: T1003
+** Reference URL: https://attack.mitre.org/techniques/T1003/
+* Technique:
+** Name: Unsecured Credentials
+** ID: T1552
+** Reference URL: https://attack.mitre.org/techniques/T1552/
+* Sub-technique:
+** Name: Private Keys
+** ID: T1552.004
+** Reference URL: https://attack.mitre.org/techniques/T1552/004/
+* 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: Domain Accounts
+** ID: T1078.002
+** Reference URL: https://attack.mitre.org/techniques/T1078/002/