Elastic Security Detection Rules

Potential Fake CAPTCHA Phishing Attack

Last updated 24 days ago on 2025-08-19
Created 24 days ago on 2025-08-19

About

Identifies potential fake CAPTCHA phishing attack based on PowerShell or Cmd argument values. Adversaries employ this technique via compromised websites with browser injects, posing either as fake CAPTCHAs to access the site or as a page loading error requiring a fix to display the page. The victim is instructed to copy and past a malicious command to the Windows Run dialog box.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: ExecutionData Source: Windows Security Event LogsData Source: Elastic DefendData Source: SysmonData Source: SentinelOneData Source: Microsoft Defender for EndpointData Source: CrowdstrikeLanguage: eql
Severity
high
Risk Score
73
MITRE ATT&CK™

Execution (TA0002)(opens in a new tab or window)

↳ Command and Scripting Interpreter (T1059)(opens in a new tab or window)

Defense Evasion (TA0005)(opens in a new tab or window)

↳ System Binary Proxy Execution (T1218)(opens in a new tab or window)

Initial Access (TA0001)(opens in a new tab or window)

↳ Phishing (T1566)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process-*logs-crowdstrike.fdr*logs-m365_defender.event-*logs-sentinel_one_cloud_funnel.*logs-system.security*logs-windows.forwarded*logs-windows.sysmon_operational-*winlogbeat-*
Related Integrations

endpoint(opens in a new tab or window)

windows(opens in a new tab or window)

system(opens in a new tab or window)

sentinel_one_cloud_funnel(opens in a new tab or window)

m365_defender(opens in a new tab or window)

crowdstrike(opens in a new tab or window)

Query
process where host.os.type == "windows" and event.type == "start" and
 process.name : ("powershell.exe", "cmd.exe", "mshta.exe") and process.parent.name : "explorer.exe" and
 process.command_line : ("*recaptcha *", "*CAPTCHA Verif*", "*complete verification*", "*Verification ID*", "*Verification Code*", "*Verification UID*",
                         "*hυmаn vаlіdаtiοn*", "*human ID*", "*Action Identificator*", "*not a robot*", "*Click OK to*", "*anti-robot test*",
                         "*Cloudflare ID*")

Install detection rules in Elastic Security

Detect Potential Fake CAPTCHA Phishing Attack in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).