Persistence via Update Orchestrator Service Hijack

  1[metadata]
  2creation_date = "2020/08/17"
  3integration = ["endpoint", "windows"]
  4maturity = "production"
  5updated_date = "2023/03/06"
  6min_stack_comments = "New fields added: required_fields, related_integrations, setup"
  7min_stack_version = "8.3.0"
  8
  9[transform]
 10[[transform.osquery]]
 11label = "Osquery - Retrieve DNS Cache"
 12query = "SELECT * FROM dns_cache"
 13
 14[[transform.osquery]]
 15label = "Osquery - Retrieve All Services"
 16query = "SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services"
 17
 18[[transform.osquery]]
 19label = "Osquery - Retrieve Services Running on User Accounts"
 20query = """
 21SELECT description, display_name, name, path, pid, service_type, start_type, status, user_account FROM services WHERE
 22NOT (user_account LIKE '%LocalSystem' OR user_account LIKE '%LocalService' OR user_account LIKE '%NetworkService' OR
 23user_account == null)
 24"""
 25
 26[[transform.osquery]]
 27label = "Osquery - Retrieve Service Unsigned Executables with Virustotal Link"
 28query = """
 29SELECT concat('https://www.virustotal.com/gui/file/', sha1) AS VtLink, name, description, start_type, status, pid,
 30services.path FROM services JOIN authenticode ON services.path = authenticode.path OR services.module_path =
 31authenticode.path JOIN hash ON services.path = hash.path WHERE authenticode.result != 'trusted'
 32"""
 33
 34
 35[rule]
 36author = ["Elastic"]
 37description = """
 38Identifies potential hijacking of the Microsoft Update Orchestrator Service to establish persistence with an integrity
 39level of SYSTEM.
 40"""
 41from = "now-9m"
 42index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*", "endgame-*"]
 43language = "eql"
 44license = "Elastic License v2"
 45name = "Persistence via Update Orchestrator Service Hijack"
 46note = """## Triage and analysis
 47
 48### Investigating Persistence via Update Orchestrator Service Hijack
 49
 50Windows Update Orchestrator Service is a DCOM service used by other components to install Windows updates that are already downloaded. Windows Update Orchestrator Service was vulnerable to elevation of privileges (any user to local system) due to an improper authorization of the callers. The vulnerability affected the Windows 10 and Windows Server Core products. Fixed by Microsoft on Patch Tuesday June 2020.
 51
 52This rule will detect uncommon processes spawned by `svchost.exe` with `UsoSvc` as the command line parameters. Attackers can leverage this technique to elevate privileges or maintain persistence.
 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- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
 61- Investigate other alerts associated with the user/host during the past 48 hours.
 62- Assess whether this behavior is prevalent in the environment by looking for similar occurrences across hosts.
 63- Examine the host for derived artifacts that indicate suspicious activities:
 64  - Analyze the process executable using a private sandboxed analysis system.
 65  - Observe and collect information about the following activities in both the sandbox and the alert subject host:
 66    - Attempts to contact external domains and addresses.
 67      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
 68      - Examine the DNS cache for suspicious or anomalous entries.
 69        - $osquery_0
 70    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
 71    - Examine the host services for suspicious or anomalous entries.
 72      - $osquery_1
 73      - $osquery_2
 74      - $osquery_3
 75  - 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.
 76- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.
 77
 78
 79### False positive analysis
 80
 81- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
 82
 83### Response and remediation
 84
 85- Initiate the incident response process based on the outcome of the triage.
 86- Isolate the involved host to prevent further post-compromise behavior.
 87- If the triage identified malware, search the environment for additional compromised hosts.
 88  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 89  - Stop suspicious processes.
 90  - Immediately block the identified indicators of compromise (IoCs).
 91  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
 92- Remove and block malicious artifacts identified during triage.
 93- 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.
 94- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 95- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 96- 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).
 97
 98## Setup
 99
100If 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 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
101"""
102references = ["https://github.com/irsl/CVE-2020-1313"]
103risk_score = 73
104rule_id = "265db8f5-fc73-4d0d-b434-6483b56372e2"
105severity = "high"
106tags = ["Elastic", "Host", "Windows", "Threat Detection", "Persistence", "CVE-2020-1313", "Investigation Guide", "Elastic Endgame"]
107timestamp_override = "event.ingested"
108type = "eql"
109
110query = '''
111process where host.os.type == "windows" and event.type == "start" and
112  process.parent.executable : "C:\\Windows\\System32\\svchost.exe" and
113  process.parent.args : "UsoSvc" and
114  not process.executable :
115          ("?:\\ProgramData\\Microsoft\\Windows\\UUS\\Packages\\*\\amd64\\MoUsoCoreWorker.exe",
116          "?:\\Windows\\System32\\UsoClient.exe",
117          "?:\\Windows\\System32\\MusNotification.exe",
118          "?:\\Windows\\System32\\MusNotificationUx.exe",
119          "?:\\Windows\\System32\\MusNotifyIcon.exe",
120          "?:\\Windows\\System32\\WerFault.exe",
121          "?:\\Windows\\System32\\WerMgr.exe",
122          "?:\\Windows\\UUS\\amd64\\MoUsoCoreWorker.exe",
123          "?:\\Windows\\System32\\MoUsoCoreWorker.exe",
124          "?:\\Windows\\UUS\\amd64\\UsoCoreWorker.exe",
125          "?:\\Windows\\System32\\UsoCoreWorker.exe",
126          "?:\\Program Files\\Common Files\\microsoft shared\\ClickToRun\\OfficeC2RClient.exe") and
127  not process.name : ("MoUsoCoreWorker.exe", "OfficeC2RClient.exe")
128'''
129
130
131[[rule.threat]]
132framework = "MITRE ATT&CK"
133[[rule.threat.technique]]
134id = "T1543"
135name = "Create or Modify System Process"
136reference = "https://attack.mitre.org/techniques/T1543/"
137[[rule.threat.technique.subtechnique]]
138id = "T1543.003"
139name = "Windows Service"
140reference = "https://attack.mitre.org/techniques/T1543/003/"
141
142
143
144[rule.threat.tactic]
145id = "TA0003"
146name = "Persistence"
147reference = "https://attack.mitre.org/tactics/TA0003/"