mirror of
https://github.com/splunk/security_content
synced 2026-06-08 17:32:49 +00:00
Michael Haag
ec5cf468e3
This PR introduces comprehensive updates to our detection analytics, focusing on tagging relevant detections with the new "Seashell Blizzard" analytic story. The changes include: Version and date updates across 20 detection files, with dates standardized to '2025-03-24' or '2025-03-25', and version numbers incremented appropriately. Analytics tagged with "Seashell Blizzard" include: ConnectWise ScreenConnect vulnerability detections (authentication bypass, path traversal) Exchange Server exploitation detections (ProxyShell, ProxyNotShell, web shell) Credential access monitoring (LSASS dumps via TaskMgr and ProcDump) Remote access software usage detections (file, process, registry) Scheduled task abuse detections SQL Server xp_cmdshell configuration changes Registry hive dumping detection Key updates: - Added "Seashell Blizzard" tag to 20 existing detections These changes enhance our ability to track and detect activities associated with the Seashell Blizzard threat actor.
76 lines
4.3 KiB
YAML
76 lines
4.3 KiB
YAML
name: ProxyShell ProxyNotShell Behavior Detected
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id: c32fab32-6aaf-492d-bfaf-acbed8e50cdf
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version: 5
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date: '2025-03-24'
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author: Michael Haag, Splunk
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status: production
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type: Correlation
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description: The following analytic identifies potential exploitation of Windows Exchange
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servers via ProxyShell or ProxyNotShell vulnerabilities, followed by post-exploitation
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activities such as running nltest, Cobalt Strike, Mimikatz, and adding new users.
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It leverages data from multiple analytic stories, requiring at least five distinct
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sources to trigger, thus reducing noise. This activity is significant as it indicates
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a high likelihood of an active compromise, potentially leading to unauthorized access,
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privilege escalation, and persistent threats within the environment. If confirmed
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malicious, attackers could gain control over the Exchange server, exfiltrate data,
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and maintain long-term access.
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data_source: []
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search: '| tstats `security_content_summariesonly` min(_time) as firstTime max(_time)
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as lastTime sum(All_Risk.calculated_risk_score) as risk_score, count(All_Risk.calculated_risk_score)
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as risk_event_count, values(All_Risk.annotations.mitre_attack.mitre_tactic_id) as
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annotations.mitre_attack.mitre_tactic_id, dc(All_Risk.annotations.mitre_attack.mitre_tactic_id)
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as mitre_tactic_id_count, values(All_Risk.analyticstories) as analyticstories values(All_Risk.annotations.mitre_attack.mitre_technique_id)
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as annotations.mitre_attack.mitre_technique_id, dc(All_Risk.annotations.mitre_attack.mitre_technique_id)
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as mitre_technique_id_count, values(All_Risk.tag) as tag, values(source) as source,
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dc(source) as source_count dc(All_Risk.analyticstories) as dc_analyticstories from
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datamodel=Risk.All_Risk where All_Risk.analyticstories IN ("ProxyNotShell","ProxyShell")
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OR (All_Risk.analyticstories IN ("ProxyNotShell","ProxyShell") AND All_Risk.analyticstories="Cobalt
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Strike") All_Risk.risk_object_type="system" by _time span=1h All_Risk.risk_object
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All_Risk.risk_object_type | `drop_dm_object_name(All_Risk)` | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`| where source_count >=5 | `proxyshell_proxynotshell_behavior_detected_filter`'
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how_to_implement: To implement this correlation, you will need to enable ProxyShell,
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ProxyNotShell and Cobalt Strike analytic stories (the anaytics themselves) and ensure
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proper data is being collected for Web and Endpoint datamodels. Run the correlation
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rule seperately to validate it is not triggering too much or generating incorrectly.
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Validate by running ProxyShell POC code and Cobalt Strike behavior.
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known_false_positives: False positives will be limited, however tune or modify the
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query as needed.
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references:
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- https://www.gteltsc.vn/blog/warning-new-attack-campaign-utilized-a-new-0day-rce-vulnerability-on-microsoft-exchange-server-12715.html
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- https://msrc-blog.microsoft.com/2022/09/29/customer-guidance-for-reported-zero-day-vulnerabilities-in-microsoft-exchange-server/
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drilldown_searches:
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- name: View the detection results for - "$risk_object$"
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search: '%original_detection_search% | search risk_object = "$risk_object$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$risk_object$"
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search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$risk_object$")
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starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime
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values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories)
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as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic)
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as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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tags:
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analytic_story:
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- ProxyShell
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- ProxyNotShell
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- Seashell Blizzard
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asset_type: Web Server
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mitre_attack_id:
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- T1190
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- T1133
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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security_domain: network
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tests:
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- name: True Positive Test
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attack_data:
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- data:
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https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/proxyshell/proxyshell-risk.log
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source: proxyshell
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sourcetype: stash
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