Svchost spawning Cmd

  1[metadata]
  2creation_date = "2020/02/18"
  3integration = ["endpoint", "windows", "system"]
  4maturity = "production"
  5min_stack_comments = "Multiple field support in the New Terms rule type was added in Elastic 8.6"
  6min_stack_version = "8.6.0"
  7updated_date = "2024/04/05"
  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[rule]
 35author = ["Elastic"]
 36description = "Identifies a suspicious parent child process relationship with cmd.exe descending from svchost.exe"
 37from = "now-9m"
 38index = ["winlogbeat-*", "logs-endpoint.events.process-*", "logs-windows.*", "logs-system.security*"]
 39language = "kuery"
 40license = "Elastic License v2"
 41name = "Svchost spawning Cmd"
 42note = """## Triage and analysis
 43
 44### Investigating Svchost spawning Cmd
 45
 46The Service Host process (SvcHost) is a system process that can host one, or multiple, Windows services in the Windows NT family of operating systems. Note that `Svchost.exe` is reserved for use by the operating system and should not be used by non-Windows services.
 47
 48This rule looks for the creation of the `cmd.exe` process with `svchost.exe` as its parent process. This is an unusual behavior that can indicate the masquerading of a malicious process as `svchost.exe` or exploitation for privilege escalation.
 49
 50> **Note**:
 51> 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.
 52
 53#### Possible investigation steps
 54
 55- 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.
 56- Investigate other alerts associated with the user/host during the past 48 hours.
 57- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
 58- Examine the host for derived artifacts that indicate suspicious activities:
 59  - Analyze the process executable using a private sandboxed analysis system.
 60  - Observe and collect information about the following activities in both the sandbox and the alert subject host:
 61    - Attempts to contact external domains and addresses.
 62      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
 63      - Examine the DNS cache for suspicious or anomalous entries.
 64        - $osquery_0
 65    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
 66    - Examine the host services for suspicious or anomalous entries.
 67      - $osquery_1
 68      - $osquery_2
 69      - $osquery_3
 70  - 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.
 71- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.
 72
 73
 74### False positive analysis
 75
 76- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
 77
 78### Response and remediation
 79
 80- Initiate the incident response process based on the outcome of the triage.
 81- Isolate the involved host to prevent further post-compromise behavior.
 82- If the triage identified malware, search the environment for additional compromised hosts.
 83  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 84  - Stop suspicious processes.
 85  - Immediately block the identified indicators of compromise (IoCs).
 86  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
 87- Remove and block malicious artifacts identified during triage.
 88- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 89- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 90- 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).
 91"""
 92references = [
 93    "https://nasbench.medium.com/demystifying-the-svchost-exe-process-and-its-command-line-options-508e9114e747",
 94]
 95risk_score = 21
 96rule_id = "fd7a6052-58fa-4397-93c3-4795249ccfa2"
 97setup = """## Setup
 98
 99If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
100events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
101Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
102`event.ingested` to @timestamp.
103For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
104"""
105severity = "low"
106tags = ["Domain: Endpoint",
107        "OS: Windows",
108        "Use Case: Threat Detection",
109        "Tactic: Execution",
110        "Resources: Investigation Guide",
111        "Data Source: Elastic Defend"
112        ]
113timeline_id = "e70679c2-6cde-4510-9764-4823df18f7db"
114timeline_title = "Comprehensive Process Timeline"
115timestamp_override = "event.ingested"
116type = "new_terms"
117
118query = '''
119host.os.type:windows and event.category:process and event.type:start and process.parent.name:"svchost.exe" and
120process.name:("cmd.exe" or "Cmd.exe" or "CMD.EXE") and
121not process.command_line : "\"cmd.exe\" /C sc control hptpsmarthealthservice 211"
122'''
123
124[[rule.filters]]
125[rule.filters.meta]
126negate = true
127[rule.filters.query.wildcard."process.args"]
128"case_insensitive" = true
129"value" = "?:\\\\Windows\\\\system32\\\\silcollector.cmd"
130
131[[rule.filters]]
132[rule.filters.meta]
133negate = true
134[rule.filters.query.wildcard."process.command_line"]
135"case_insensitive" = true
136"value" = "*?:\\\\Program Files\\\\Npcap\\\\CheckStatus.bat*"
137
138
139[[rule.filters]]
140[rule.filters.meta]
141negate = true
142[rule.filters.query.wildcard."process.command_line"]
143"case_insensitive" = true
144"value" = "*?:\\\\Program Files*\\\\Pulseway\\\\watchdog.bat*"
145
146[[rule.filters]]
147[rule.filters.meta]
148negate = true
149[rule.filters.query.wildcard."process.command_line"]
150"case_insensitive" = true
151"value" = "cmd /C \".\\\\inetsrv\\\\iissetup.exe /keygen \""
152
153[[rule.threat]]
154framework = "MITRE ATT&CK"
155
156[[rule.threat.technique]]
157id = "T1059"
158name = "Command and Scripting Interpreter"
159reference = "https://attack.mitre.org/techniques/T1059/"
160
161[rule.threat.tactic]
162id = "TA0002"
163name = "Execution"
164reference = "https://attack.mitre.org/tactics/TA0002/"
165
166[rule.new_terms]
167field = "new_terms_fields"
168value = ["host.id", "process.command_line", "user.id"]
169
170[[rule.new_terms.history_window_start]]
171field = "history_window_start"
172value = "now-14d"