Svchost spawning Cmd

  1[metadata]
  2creation_date = "2020/02/18"
  3integration = ["endpoint", "windows", "system"]
  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[rule]
 33author = ["Elastic"]
 34description = "Identifies a suspicious parent child process relationship with cmd.exe descending from svchost.exe"
 35from = "now-9m"
 36index = ["winlogbeat-*", "logs-endpoint.events.process-*", "logs-windows.*", "logs-system.security*"]
 37language = "kuery"
 38license = "Elastic License v2"
 39name = "Svchost spawning Cmd"
 40note = """## Triage and analysis
 41
 42### Investigating Svchost spawning Cmd
 43
 44The 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.
 45
 46This 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.
 47
 48> **Note**:
 49> 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.
 50
 51#### Possible investigation steps
 52
 53- 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.
 54- Investigate other alerts associated with the user/host during the past 48 hours.
 55- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
 56- Examine the host for derived artifacts that indicate suspicious activities:
 57  - Analyze the process executable using a private sandboxed analysis system.
 58  - Observe and collect information about the following activities in both the sandbox and the alert subject host:
 59    - Attempts to contact external domains and addresses.
 60      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
 61      - Examine the DNS cache for suspicious or anomalous entries.
 62        - $osquery_0
 63    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
 64    - Examine the host services for suspicious or anomalous entries.
 65      - $osquery_1
 66      - $osquery_2
 67      - $osquery_3
 68  - 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.
 69- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target host after the registry modification.
 70
 71
 72### False positive analysis
 73
 74- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
 75
 76### Response and remediation
 77
 78- Initiate the incident response process based on the outcome of the triage.
 79- Isolate the involved host to prevent further post-compromise behavior.
 80- If the triage identified malware, search the environment for additional compromised hosts.
 81  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 82  - Stop suspicious processes.
 83  - Immediately block the identified indicators of compromise (IoCs).
 84  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
 85- Remove and block malicious artifacts identified during triage.
 86- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 87- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 88- 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).
 89"""
 90references = [
 91    "https://nasbench.medium.com/demystifying-the-svchost-exe-process-and-its-command-line-options-508e9114e747",
 92]
 93risk_score = 21
 94rule_id = "fd7a6052-58fa-4397-93c3-4795249ccfa2"
 95setup = """## Setup
 96
 97If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
 98events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
 99Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
100`event.ingested` to @timestamp.
101For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
102"""
103severity = "low"
104tags = ["Domain: Endpoint",
105        "OS: Windows",
106        "Use Case: Threat Detection",
107        "Tactic: Execution",
108        "Resources: Investigation Guide",
109        "Data Source: Elastic Defend"
110        ]
111timeline_id = "e70679c2-6cde-4510-9764-4823df18f7db"
112timeline_title = "Comprehensive Process Timeline"
113timestamp_override = "event.ingested"
114type = "new_terms"
115
116query = '''
117host.os.type:windows and event.category:process and event.type:start and process.parent.name:"svchost.exe" and
118process.name:("cmd.exe" or "Cmd.exe" or "CMD.EXE") and
119not process.command_line : "\"cmd.exe\" /C sc control hptpsmarthealthservice 211"
120'''
121
122[[rule.filters]]
123[rule.filters.meta]
124negate = true
125[rule.filters.query.wildcard."process.args"]
126"case_insensitive" = true
127"value" = "?:\\\\Windows\\\\system32\\\\silcollector.cmd"
128
129[[rule.filters]]
130[rule.filters.meta]
131negate = true
132[rule.filters.query.wildcard."process.command_line"]
133"case_insensitive" = true
134"value" = "*?:\\\\Program Files\\\\Npcap\\\\CheckStatus.bat*"
135
136
137[[rule.filters]]
138[rule.filters.meta]
139negate = true
140[rule.filters.query.wildcard."process.command_line"]
141"case_insensitive" = true
142"value" = "*?:\\\\Program Files*\\\\Pulseway\\\\watchdog.bat*"
143
144[[rule.filters]]
145[rule.filters.meta]
146negate = true
147[rule.filters.query.wildcard."process.command_line"]
148"case_insensitive" = true
149"value" = "cmd /C \".\\\\inetsrv\\\\iissetup.exe /keygen \""
150
151[[rule.threat]]
152framework = "MITRE ATT&CK"
153
154[[rule.threat.technique]]
155id = "T1059"
156name = "Command and Scripting Interpreter"
157reference = "https://attack.mitre.org/techniques/T1059/"
158
159[rule.threat.tactic]
160id = "TA0002"
161name = "Execution"
162reference = "https://attack.mitre.org/tactics/TA0002/"
163
164[rule.new_terms]
165field = "new_terms_fields"
166value = ["host.id", "process.command_line", "user.id"]
167
168[[rule.new_terms.history_window_start]]
169field = "history_window_start"
170value = "now-14d"