Behavioral Detection of External Website Defacement across Platforms

Technique Detected:  External Defacement | T1491.002

ID: DET0590
Domains: Enterprise
Analytics: AN1622, AN1623, AN1624, AN1625
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1622

Adversary modifies externally-facing web content by accessing and overwriting hosted HTML/JS/CSS files, typically following web shell deployment, credential abuse, or exploitation of web application vulnerabilities.

Log Sources
Data Component Name Channel
File Modification (DC0061) WinEventLog:Security EventCode=4663
Network Traffic Content (DC0085) NSM:Connections Unusual POST requests to admin or upload endpoints
Process Creation (DC0032) WinEventLog:Sysmon EventCode=1
Mutable Elements
Field Description
target_directory Web root folder varies by environment, e.g., C:\inetpub\wwwroot
UserContext May vary based on which service account hosts the website
TimeWindow Time between webshell upload and file overwrite may vary

AN1623

Adversary compromises a Linux-based web server and modifies hosted web files by exploiting upload vulnerabilities, remote code execution, or replacing index.html via SSH/webshell.

Log Sources
Data Component Name Channel
File Modification (DC0061) auditd:SYSCALL open/write syscalls targeting web directory files
Logon Session Metadata (DC0088) NSM:Connections Successful sudo or ssh from unknown IPs
Network Traffic Content (DC0085) NSM:Flow Suspicious POSTs to upload endpoints
Mutable Elements
Field Description
web_root May differ (e.g., /var/www/html, /srv/http, etc.)
payload_hash Adversary content hash may change across campaigns
UserContext Can range from apache/nginx user to root if escalated

AN1624

Adversary modifies web-facing content on macOS via web development environments like MAMP or misconfigured Apache instances, typically with access to the hosting user account or via persistence tools.

Log Sources
Data Component Name Channel
File Modification (DC0061) macos:unifiedlog Terminal/Editor processes modifying web folder
Logon Session Metadata (DC0088) macos:unifiedlog loginwindow or sshd events with external IP
Mutable Elements
Field Description
web_root_dir May include ~/Sites or custom Apache paths
editor_name Text editor or script modifying the files may vary (e.g., nano, VS Code)

AN1625

Adversary modifies content in cloud-hosted websites (e.g., AWS S3-backed, Azure Blob-hosted sites) by gaining access to management consoles or APIs and uploading altered HTML/JS files.

Log Sources
Data Component Name Channel
File Creation (DC0039) AWS:CloudTrail PutObject
Cloud Storage Enumeration (DC0017) AWS:CloudTrail ListBuckets
Cloud Storage Access (DC0025) AWS:CloudTrail GetObject
Mutable Elements
Field Description
bucket_name Website bucket name varies per org
region Adversary may target multi-region failover setups
IAMRole Attack may leverage stolen cross-account roles or elevated policies