Potential CVE-2025-33053 Exploitation

[metadata]
creation_date = "2025/06/11"
integration = ["endpoint", "windows", "m365_defender", "sentinel_one_cloud_funnel"]
maturity = "production"
updated_date = "2026/03/24"

[rule]
author = ["Elastic"]
description = """
Identifies a suspicious Diagnostics Utility for Internet Explorer child process. This may indicate the successful exploitation of the vulnerability CVE-2025-33053.
"""
from = "now-9m"
index = [
    "logs-endpoint.events.process-*",
    "winlogbeat-*",
    "logs-windows.sysmon_operational-*",
    "endgame-*",
    "logs-m365_defender.event-*",
    "logs-sentinel_one_cloud_funnel.*",
]
language = "eql"
license = "Elastic License v2"
name = "Potential CVE-2025-33053 Exploitation"
note = """## Triage and analysis

### Investigating Potential CVE-2025-33053 Exploitation

### Possible investigation steps

- Review the process details to confirm the suspicious child process was indeed started by iediagcmd.exe.
- Check any URL file type creation before the alert and review the source of those files.
- Investigate the process tree and make sure all descendant processes are terminated.
- Examine the network activity associated with the suspicious process to detect any unauthorized data exfiltration or communication with known malicious IP addresses.
- Assess the system for any additional indicators of compromise, such as unexpected changes in system files or registry keys, which might suggest a broader attack.

### False positive analysis

- This behavior is very rare and should be highly suspicious.

### Response and remediation

- Isolate the affected system from the network to prevent further spread of the potential threat and to contain any malicious activity.
- Terminate the suspicious child process identified in the alert.
- Conduct a thorough scan of the affected system using updated antivirus or endpoint detection and response (EDR) tools to identify and remove any additional malicious files or processes.
- Escalate the incident to the security operations center (SOC) or incident response team for further investigation and to determine if the threat is part of a larger attack campaign.
- Implement additional monitoring and alerting for similar suspicious activities involving explorer.exe to enhance detection capabilities and prevent recurrence.
- Review and update endpoint security policies to restrict the execution of potentially malicious URL files."""
references = [
     "https://research.checkpoint.com/2025/stealth-falcon-zero-day/", 
     "https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-33053",
]
risk_score = 73
rule_id = "5e23495f-09e2-4484-8235-bdb150d698c9"
severity = "high"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Initial Access",
    "Tactic: Defense Evasion",
    "Data Source: Elastic Endgame",
    "Data Source: Elastic Defend",
    "Data Source: Sysmon",
    "Data Source: Microsoft Defender for Endpoint",
    "Data Source: SentinelOne",
    "Resources: Investigation Guide",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
  process.parent.executable : "C:\\Program Files\\Internet Explorer\\iediagcmd.exe" and
  process.name : ("route.exe", "netsh.exe", "ipconfig.exe", "dxdiag.exe", "conhost.exe", "makecab.exe") and
  process.executable != null and
  not process.executable : ("C:\\Windows\\System32\\route.exe",
                            "C:\\Windows\\System32\\netsh.exe",
                            "C:\\Windows\\System32\\ipconfig.exe",
                            "C:\\Windows\\System32\\dxdiag.exe",
                            "C:\\Windows\\System32\\conhost.exe",
                            "C:\\Windows\\System32\\makecab.exe")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1566"
name = "Phishing"
reference = "https://attack.mitre.org/techniques/T1566/"

[[rule.threat.technique.subtechnique]]
id = "T1566.001"
name = "Spearphishing Attachment"
reference = "https://attack.mitre.org/techniques/T1566/001/"

[[rule.threat.technique.subtechnique]]
id = "T1566.002"
name = "Spearphishing Link"
reference = "https://attack.mitre.org/techniques/T1566/002/"

[rule.threat.tactic]
id = "TA0001"
name = "Initial Access"
reference = "https://attack.mitre.org/tactics/TA0001/"

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1036"
name = "Masquerading"
reference = "https://attack.mitre.org/techniques/T1036/"

[[rule.threat.technique.subtechnique]]
id = "T1036.005"
name = "Match Legitimate Resource Name or Location"
reference = "https://attack.mitre.org/techniques/T1036/005/"

[[rule.threat.technique]]
id = "T1218"
name = "System Binary Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1218/"

[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1203"
name = "Exploitation for Client Execution"
reference = "https://attack.mitre.org/techniques/T1203/"

[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"