SUNBURST Command and Control Activity

  1[metadata]
  2creation_date = "2020/12/14"
  3integration = ["endpoint"]
  4maturity = "production"
  5updated_date = "2024/05/21"
  6
  7[transform]
  8[[transform.osquery]]
  9label = "Osquery - Retrieve DNS Cache"
 10query = "SELECT * FROM dns_cache"
 11
 12[[transform.osquery]]
 13label = "Osquery - Retrieve All Services"
 14query = "SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services"
 15
 16[[transform.osquery]]
 17label = "Osquery - Retrieve Services Running on User Accounts"
 18query = """
 19SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services WHERE
 20NOT (user_account LIKE '%LocalSystem' OR user_account LIKE '%LocalService' OR user_account LIKE '%NetworkService' OR
 21user_account == null)
 22"""
 23
 24[[transform.osquery]]
 25label = "Osquery - Retrieve Service Unsigned Executables with Virustotal Link"
 26query = """
 27SELECT concat('https://www.virustotal.com/gui/file/', sha1) AS VtLink, name, description, start_type, status, pid,
 28services.path FROM services JOIN authenticode ON services.path = authenticode.path OR services.module_path =
 29authenticode.path JOIN hash ON services.path = hash.path WHERE authenticode.result != 'trusted'
 30"""
 31
 32
 33[rule]
 34author = ["Elastic"]
 35description = """
 36The malware known as SUNBURST targets the SolarWind's Orion business software for command and control. This rule detects
 37post-exploitation command and control activity of the SUNBURST backdoor.
 38"""
 39from = "now-9m"
 40index = ["logs-endpoint.events.network-*"]
 41language = "eql"
 42license = "Elastic License v2"
 43name = "SUNBURST Command and Control Activity"
 44note = """## Triage and analysis
 45
 46### Investigating SUNBURST Command and Control Activity
 47
 48SUNBURST is a trojanized version of a digitally signed SolarWinds Orion plugin called SolarWinds.Orion.Core.BusinessLayer.dll. The plugin contains a backdoor that communicates via HTTP to third-party servers. After an initial dormant period of up to two weeks, SUNBURST may retrieve and execute commands that instruct the backdoor to transfer files, execute files, profile the system, reboot the system, and disable system services. The malware's network traffic attempts to blend in with legitimate SolarWinds activity by imitating the Orion Improvement Program (OIP) protocol, and the malware stores persistent state data within legitimate plugin configuration files. The backdoor uses multiple obfuscated blocklists to identify processes, services, and drivers associated with forensic and anti-virus tools.
 49
 50More details on SUNBURST can be found on the [Mandiant Report](https://www.mandiant.com/resources/sunburst-additional-technical-details).
 51
 52This rule identifies suspicious network connections that attempt to blend in with legitimate SolarWinds activity by imitating the Orion Improvement Program (OIP) protocol behavior.
 53
 54> **Note**:
 55> This investigation guide uses the [Osquery Markdown Plugin](https://www.elastic.co/guide/en/security/master/invest-guide-run-osquery.html) introduced in Elastic Stack version 8.5.0. Older Elastic Stack versions will display unrendered Markdown in this guide.
 56
 57#### Possible investigation steps
 58
 59- 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.
 60- Examine the host for derived artifacts that indicate suspicious activities:
 61  - Analyze the executable involved using a private sandboxed analysis system.
 62  - Observe and collect information about the following activities in both the sandbox and the alert subject host:
 63    - Attempts to contact external domains and addresses.
 64      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
 65      - Examine the DNS cache for suspicious or anomalous entries.
 66        - $osquery_0
 67    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
 68    - Examine the host services for suspicious or anomalous entries.
 69      - $osquery_1
 70      - $osquery_2
 71      - $osquery_3
 72  - 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.
 73- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.
 74
 75### False positive analysis
 76
 77- This activity should not happen legitimately. The security team should address any potential benign true positive (B-TP), as this configuration can put the environment at risk.
 78
 79### Response and remediation
 80
 81- Initiate the incident response process based on the outcome of the triage.
 82- Isolate the involved host to prevent further post-compromise behavior.
 83- If the triage identified malware, search the environment for additional compromised hosts.
 84  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 85  - Stop suspicious processes.
 86  - Immediately block the identified indicators of compromise (IoCs).
 87  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
 88- Remove and block malicious artifacts identified during triage.
 89- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 90- Reimage the host operating system and restore compromised files to clean versions.
 91- Upgrade SolarWinds systems to the latest version to eradicate the chance of reinfection by abusing the same vector.
 92- 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).
 93"""
 94references = [
 95    "https://www.fireeye.com/blog/threat-research/2020/12/evasive-attacker-leverages-solarwinds-supply-chain-compromises-with-sunburst-backdoor.html",
 96]
 97risk_score = 73
 98rule_id = "22599847-5d13-48cb-8872-5796fee8692b"
 99severity = "high"
100tags = [
101    "Domain: Endpoint",
102    "OS: Windows",
103    "Use Case: Threat Detection",
104    "Tactic: Command and Control",
105    "Resources: Investigation Guide",
106    "Data Source: Elastic Defend",
107]
108timestamp_override = "event.ingested"
109type = "eql"
110
111query = '''
112network where host.os.type == "windows" and event.type == "protocol" and network.protocol == "http" and
113  process.name : ("ConfigurationWizard.exe",
114                  "NetFlowService.exe",
115                  "NetflowDatabaseMaintenance.exe",
116                  "SolarWinds.Administration.exe",
117                  "SolarWinds.BusinessLayerHost.exe",
118                  "SolarWinds.BusinessLayerHostx64.exe",
119                  "SolarWinds.Collector.Service.exe",
120                  "SolarwindsDiagnostics.exe") and
121  (
122    (
123      (http.request.body.content : "*/swip/Upload.ashx*" and http.request.body.content : ("POST*", "PUT*")) or
124      (http.request.body.content : ("*/swip/SystemDescription*", "*/swip/Events*") and http.request.body.content : ("GET*", "HEAD*"))
125    ) and
126    not http.request.body.content : "*solarwinds.com*"
127  )
128'''
129
130
131[[rule.threat]]
132framework = "MITRE ATT&CK"
133[[rule.threat.technique]]
134id = "T1071"
135name = "Application Layer Protocol"
136reference = "https://attack.mitre.org/techniques/T1071/"
137[[rule.threat.technique.subtechnique]]
138id = "T1071.001"
139name = "Web Protocols"
140reference = "https://attack.mitre.org/techniques/T1071/001/"
141
142
143
144[rule.threat.tactic]
145id = "TA0011"
146name = "Command and Control"
147reference = "https://attack.mitre.org/tactics/TA0011/"
148[[rule.threat]]
149framework = "MITRE ATT&CK"
150[[rule.threat.technique]]
151id = "T1195"
152name = "Supply Chain Compromise"
153reference = "https://attack.mitre.org/techniques/T1195/"
154[[rule.threat.technique.subtechnique]]
155id = "T1195.002"
156name = "Compromise Software Supply Chain"
157reference = "https://attack.mitre.org/techniques/T1195/002/"
158
159
160
161[rule.threat.tactic]
162id = "TA0001"
163name = "Initial Access"
164reference = "https://attack.mitre.org/tactics/TA0001/"