Privilege Escalation via Named Pipe Impersonation

  1[metadata]
  2creation_date = "2020/11/23"
  3integration = ["endpoint", "windows", "system"]
  4maturity = "production"
  5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
  6min_stack_version = "8.3.0"
  7updated_date = "2024/03/28"
  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 a privilege escalation attempt via named pipe impersonation. An adversary may abuse this technique by
 39utilizing a framework such Metasploit's meterpreter getsystem command.
 40"""
 41from = "now-9m"
 42index = ["winlogbeat-*", "logs-endpoint.events.process-*", "logs-windows.*", "endgame-*", "logs-system.security*"]
 43language = "eql"
 44license = "Elastic License v2"
 45name = "Privilege Escalation via Named Pipe Impersonation"
 46note = """## Triage and analysis
 47
 48### Investigating Privilege Escalation via Named Pipe Impersonation
 49
 50A named pipe is a type of inter-process communication (IPC) mechanism used in operating systems like Windows, which allows two or more processes to communicate with each other by sending and receiving data through a well-known point.
 51
 52Attackers can abuse named pipes to elevate their privileges by impersonating the security context in which they execute code. Metasploit, for example, creates a service and a random pipe, and then uses the service to connect to the pipe and impersonate the service security context, which is SYSTEM.
 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 other alerts associated with the user/host during the past 48 hours.
 61- Inspect the host for suspicious or abnormal behavior in the alert timeframe.
 62- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
 63- Examine the host for derived artifacts that indicate suspicious activities:
 64  - If any suspicious processes were found, examine 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
 77### False positive analysis
 78
 79- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
 80
 81### Response and remediation
 82
 83- Initiate the incident response process based on the outcome of the triage.
 84- Isolate the involved host to prevent further post-compromise behavior.
 85- If the triage identified malware, search the environment for additional compromised hosts.
 86  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 87  - Stop suspicious processes.
 88  - Immediately block the identified indicators of compromise (IoCs).
 89  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
 90- Remove and block malicious artifacts identified during triage.
 91- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
 92- 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.
 93- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 94- 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).
 95"""
 96references = [
 97    "https://www.ired.team/offensive-security/privilege-escalation/windows-namedpipes-privilege-escalation",
 98    "https://www.cobaltstrike.com/blog/what-happens-when-i-type-getsystem/",
 99    "https://redcanary.com/blog/getsystem-offsec/",
100]
101risk_score = 73
102rule_id = "3ecbdc9e-e4f2-43fa-8cca-63802125e582"
103setup = """## Setup
104
105If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
106events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
107Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
108`event.ingested` to @timestamp.
109For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
110"""
111severity = "high"
112tags = [
113    "Domain: Endpoint",
114    "OS: Windows",
115    "Use Case: Threat Detection",
116    "Tactic: Privilege Escalation",
117    "Resources: Investigation Guide",
118    "Data Source: Elastic Endgame",
119    "Data Source: Elastic Defend"
120]
121timestamp_override = "event.ingested"
122type = "eql"
123
124query = '''
125process where host.os.type == "windows" and event.type == "start" and
126 (process.name : ("Cmd.Exe", "PowerShell.EXE") or ?process.pe.original_file_name in ("Cmd.Exe", "PowerShell.EXE")) and
127 process.args : "echo" and process.args : ">" and process.args : "\\\\.\\pipe\\*"
128'''
129
130
131[[rule.threat]]
132framework = "MITRE ATT&CK"
133[[rule.threat.technique]]
134id = "T1134"
135name = "Access Token Manipulation"
136reference = "https://attack.mitre.org/techniques/T1134/"
137
138
139[rule.threat.tactic]
140id = "TA0004"
141name = "Privilege Escalation"
142reference = "https://attack.mitre.org/tactics/TA0004/"