Privilege Escalation via Named Pipe Impersonation

  1[metadata]
  2creation_date = "2020/11/23"
  3integration = ["endpoint", "windows", "system", "m365_defender", "sentinel_one_cloud_funnel", "crowdstrike"]
  4maturity = "production"
  5updated_date = "2024/11/02"
  6min_stack_version = "8.14.0"
  7min_stack_comments = "Breaking change at 8.14.0 for the Windows Integration."
  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 = [
 43    "winlogbeat-*",
 44    "logs-endpoint.events.process-*",
 45    "logs-windows.forwarded*",
 46    "logs-windows.sysmon_operational-*",
 47    "endgame-*",
 48    "logs-system.security*",
 49    "logs-m365_defender.event-*",
 50    "logs-sentinel_one_cloud_funnel.*",
 51    "logs-crowdstrike.fdr*",
 52]
 53language = "eql"
 54license = "Elastic License v2"
 55name = "Privilege Escalation via Named Pipe Impersonation"
 56note = """## Triage and analysis
 57
 58### Investigating Privilege Escalation via Named Pipe Impersonation
 59
 60A 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.
 61
 62Attackers 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.
 63
 64> **Note**:
 65> 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.
 66
 67#### Possible investigation steps
 68
 69- 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.
 70- Investigate other alerts associated with the user/host during the past 48 hours.
 71- Inspect the host for suspicious or abnormal behavior in the alert timeframe.
 72- Investigate any abnormal behavior by the subject process such as network connections, registry or file modifications, and any spawned child processes.
 73- Examine the host for derived artifacts that indicate suspicious activities:
 74  - If any suspicious processes were found, examine the process executable using a private sandboxed analysis system.
 75  - Observe and collect information about the following activities in both the sandbox and the alert subject host:
 76    - Attempts to contact external domains and addresses.
 77      - Use the Elastic Defend network events to determine domains and addresses contacted by the subject process by filtering by the process' `process.entity_id`.
 78      - Examine the DNS cache for suspicious or anomalous entries.
 79        - $osquery_0
 80    - Use the Elastic Defend registry events to examine registry keys accessed, modified, or created by the related processes in the process tree.
 81    - Examine the host services for suspicious or anomalous entries.
 82      - $osquery_1
 83      - $osquery_2
 84      - $osquery_3
 85  - 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.
 86
 87### False positive analysis
 88
 89- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
 90
 91### Response and remediation
 92
 93- Initiate the incident response process based on the outcome of the triage.
 94- Isolate the involved host to prevent further post-compromise behavior.
 95- If the triage identified malware, search the environment for additional compromised hosts.
 96  - Implement temporary network rules, procedures, and segmentation to contain the malware.
 97  - Stop suspicious processes.
 98  - Immediately block the identified indicators of compromise (IoCs).
 99  - Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that attackers could use to reinfect the system.
100- Remove and block malicious artifacts identified during triage.
101- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
102- 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.
103- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
104- 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).
105"""
106references = [
107    "https://www.ired.team/offensive-security/privilege-escalation/windows-namedpipes-privilege-escalation",
108    "https://www.cobaltstrike.com/blog/what-happens-when-i-type-getsystem/",
109    "https://redcanary.com/blog/getsystem-offsec/",
110]
111risk_score = 73
112rule_id = "3ecbdc9e-e4f2-43fa-8cca-63802125e582"
113severity = "high"
114tags = [
115    "Domain: Endpoint",
116    "OS: Windows",
117    "Use Case: Threat Detection",
118    "Tactic: Privilege Escalation",
119    "Resources: Investigation Guide",
120    "Data Source: Elastic Endgame",
121    "Data Source: Elastic Defend",
122    "Data Source: System",
123    "Data Source: Microsoft Defender for Endpoint",
124    "Data Source: Sysmon",
125    "Data Source: SentinelOne",
126    "Data Source: Crowdstrike",
127]
128timestamp_override = "event.ingested"
129type = "eql"
130
131query = '''
132process where host.os.type == "windows" and event.type == "start" and
133 (process.name : ("Cmd.Exe", "PowerShell.EXE") or ?process.pe.original_file_name in ("Cmd.Exe", "PowerShell.EXE")) and
134 process.args : "echo" and process.args : ">" and process.args : "\\\\.\\pipe\\*"
135'''
136
137
138[[rule.threat]]
139framework = "MITRE ATT&CK"
140[[rule.threat.technique]]
141id = "T1134"
142name = "Access Token Manipulation"
143reference = "https://attack.mitre.org/techniques/T1134/"
144
145
146[rule.threat.tactic]
147id = "TA0004"
148name = "Privilege Escalation"
149reference = "https://attack.mitre.org/tactics/TA0004/"