investigating-insider-threat-indicators调查内部威胁（Insider Threat）指标，包括数据渗漏（Data Exfiltration）尝试、未授权访问模式、 策略违规和离职前行为，结合 SIEM 分析、DLP 告警和 HR 数据关联进行调查。 适用于 SOC 团队收到 HR 内部威胁转介、检测到员工异常数据移动， 或需要为潜在内部威胁建立调查时间线时。
Independent GitHub snapshot · Automated classification · Original documentation governs
以下情况使用本技能：
不适用于未获得适当法律授权的情况——内部威胁调查必须在监控开始前与 HR、法务和隐私团队协调。
开始任何监控前，确保获得适当授权：
内部威胁调查授权
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案例 ID： IT-2024-0089
调查对象： [员工姓名] — [部门]
授权人： [CISO / 总法律顾问]
转介来源： HR — 员工提交辞职，两周通知期
理由： 员工可访问商业机密和客户 PII
范围： 邮件、文件访问、USB、云存储、打印
持续时间： 2024-03-15 至 2024-03-29（通知期）
隐私审查： 已完成——符合可接受使用策略
查询调查对象的综合活动：
index=* (user="jsmith" OR src_user="jsmith" OR sender="jsmith@company.com"
OR SubjectUserName="jsmith")
earliest="2024-03-01" latest=now
| eval event_category = case(
sourcetype LIKE "%dlp%", "DLP",
sourcetype LIKE "%proxy%", "Web 访问",
sourcetype LIKE "%email%", "邮件",
sourcetype LIKE "%WinEventLog%", "终端",
sourcetype LIKE "%o365%", "云",
sourcetype LIKE "%vpn%", "VPN",
sourcetype LIKE "%badge%", "物理访问",
1=1, sourcetype
)
| stats count by event_category, sourcetype, _time
| timechart span=1d count by event_category
批量文件下载（SharePoint/OneDrive）：
index=o365 sourcetype="o365:management:activity" Operation IN ("FileDownloaded", "FileSynced")
UserId="jsmith@company.com" earliest=-30d
| stats count AS downloads, sum(eval(if(isnotnull(FileSize), FileSize, 0))) AS total_bytes,
dc(SourceFileName) AS unique_files
by UserId, SiteUrl, _time
| bin _time span=1d
| eval total_gb = round(total_bytes / 1073741824, 2)
| where downloads > 50 OR total_gb > 1
| sort - total_gb
USB/可移动媒体使用：
index=sysmon EventCode=1 Computer="WORKSTATION-JSMITH"
(CommandLine="*removable*" OR CommandLine="*usb*"
OR Image="*\\xcopy*" OR Image="*\\robocopy*")
| table _time, Computer, User, Image, CommandLine
| append [
search index=endpoint sourcetype="endpoint:device_connect"
user="jsmith" device_type="removable"
| table _time, user, device_name, device_serial, action
]
| sort _time
基于邮件的渗漏：
index=email sourcetype="o365:messageTrace"
SenderAddress="jsmith@company.com"
| eval is_external = if(match(RecipientAddress, "@company\.comquot;), 0, 1)
| eval has_attachment = if(isnotnull(AttachmentName), 1, 0)
| stats count AS total_emails,
sum(is_external) AS external_emails,
sum(has_attachment) AS with_attachments,
sum(eval(if(is_external=1 AND has_attachment=1, 1, 0))) AS external_with_attach,
sum(Size) AS total_size_bytes
by SenderAddress
| eval external_attach_pct = round(external_with_attach / total_emails * 100, 1)
| eval total_size_mb = round(total_size_bytes / 1048576, 1)
云存储上传检测：
index=proxy user="jsmith"
(dest IN ("*dropbox.com", "*drive.google.com", "*onedrive.live.com",
"*box.com", "*wetransfer.com", "*mega.nz")
OR category="cloud-storage")
http_method=POST
| stats count AS uploads, sum(bytes_out) AS total_uploaded
by user, dest, category
| eval uploaded_mb = round(total_uploaded / 1048576, 1)
| sort - uploaded_mb
访问正常职责范围之外的敏感系统：
index=auth user="jsmith" action=success earliest=-30d
| stats dc(app) AS unique_apps, values(app) AS apps_accessed by user
| join user type=left [
| inputlookup role_app_mapping.csv
| search role="Financial Analyst"
| stats values(authorized_app) AS authorized_apps by role
| eval user="jsmith"
]
| eval unauthorized = mvfilter(NOT match(apps_accessed, mvjoin(authorized_apps, "|")))
| where isnotnull(unauthorized)
| table user, unauthorized, authorized_apps
下班时间和周末活动：
index=* user="jsmith" earliest=-30d
| eval hour = tonumber(strftime(_time, "%H"))
| eval is_offhours = if(hour < 7 OR hour > 19, 1, 0)
| eval day = strftime(_time, "%A")
| eval is_weekend = if(day IN ("Saturday", "Sunday"), 1, 0)
| stats count AS total, sum(is_offhours) AS offhours, sum(is_weekend) AS weekend by user
| eval offhours_pct = round(offhours / total * 100, 1)
| eval weekend_pct = round(weekend / total * 100, 1)
将活动与辞职时间线进行比较：
| makeresults
| eval user="jsmith",
resignation_date="2024-03-15",
last_day="2024-03-29",
access_revocation="2024-03-29 17:00"
| join user [
search index=* user="jsmith" earliest=-90d
| bin _time span=1d
| stats count AS daily_events, dc(sourcetype) AS data_sources by user, _time
]
| eval phase = case(
_time < relative_time(now(), "-30d"), "正常（辞职前）",
_time >= strptime(resignation_date, "%Y-%m-%d") AND _time <= strptime(last_day, "%Y-%m-%d"),
"通知期",
1=1, "过渡期"
)
| chart avg(daily_events) AS avg_events by phase
门禁/物理访问关联：
index=badge_access employee_id="jsmith" earliest=-30d
| stats count AS badge_events, values(door_name) AS doors_accessed,
earliest(_time) AS first_badge, latest(_time) AS last_badge by employee_id
| eval areas = mvcount(doors_accessed)
维护所有收集证据的监管链：
import hashlib
import json
from datetime import datetime
evidence_log = {
"case_id": "IT-2024-0089",
"investigator": "soc_analyst_tier2",
"collection_time": datetime.utcnow().isoformat(),
"items": [
{
"item_id": "EV-001",
"description": "Splunk 导出——所有用户活动 2024-03-01 至 2024-03-15",
"file": "jsmith_activity_export.csv",
"sha256": hashlib.sha256(open("jsmith_activity_export.csv", "rb").read()).hexdigest(),
"collected_by": "analyst_doe",
"collection_method": "Splunk 搜索导出"
},
{
"item_id": "EV-002",
"description": "DLP 告警详情——47 次策略违规",
"file": "dlp_alerts_jsmith.json",
"sha256": hashlib.sha256(open("dlp_alerts_jsmith.json", "rb").read()).hexdigest(),
"collected_by": "analyst_doe",
"collection_method": "Microsoft Purview 导出"
}
]
}
with open(f"evidence_log_{evidence_log['case_id']}.json", "w") as f:
json.dump(evidence_log, f, indent=2)
| 术语 | 定义 |
|---|---|
| 内部威胁（Insider Threat） | 拥有合法访问权限的个人出于未授权目的滥用该权限带来的风险 |
| 数据渗漏（Data Exfiltration） | 通过邮件、USB、云或其他渠道将数据未经授权地传输到组织外部 |
| DLP | 数据丢失防护（Data Loss Prevention）——根据内容策略监控和阻止未授权数据传输的技术 |
| 通知期监控（Notice Period Monitoring） | 在员工辞职到离职期间对其进行的强化监控 |
| 监管链（Chain of Custody） | 确保取证完整性的文档化证据处理程序，用于潜在的法律诉讼 |
| 知悉必要原则违规（Need-to-Know Violation） | 访问超出员工职责或当前任务所需的信息或系统 |
内部威胁调查报告 — IT-2024-0089
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对象： jsmith（金融分析师，财务部）
期间： 2024-03-01 至 2024-03-15
状态： 员工于 2024-03-15 辞职，最后工作日 2024-03-29
主要发现：
[高] 从 SharePoint 下载 3,847 个文件（12.4 GB）——同类平均值的 10 倍
[高] 通知期内连接 USB 设备 14 次（上月 0 次）
[高] 向个人 Gmail 发送 187 封带附件邮件
[中] 通知期内下班时间活动增加 340%
[中] 访问 HR 薪酬数据库 3 次（超出职责范围）
时间线：
3 月 01-14 日：正常活动基线（平均每天 150 个事件）
3 月 15 日：提交辞职（活动激增至 890 个事件）
3 月 16-17 日：周末访问——2,100 次 SharePoint 下载
3 月 18 日：首次连接 USB 设备，触发 DLP 告警
已收集证据： 4 项（SHA-256 已验证，监管链已记录）
建议： 建议立即撤销访问权限
证据包已准备好供法务审查