An adversary may deface systems external to an organization in an attempt to deliver messaging, intimidate, or otherwise mislead an organization or users. External Defacement may ultimately cause users to distrust the systems and to question/discredit the system’s integrity. Externally-facing websites are a common victim of defacement; often targeted by adversary and hacktivist groups in order to push a political message or spread propaganda.(Citation: FireEye Cyber Threats to Media Industries)(Citation: Kevin Mandia Statement to US Senate Committee on Intelligence)(Citation: Anonymous Hackers Deface Russian Govt Site) External Defacement may be used as a catalyst to trigger events, or as a response to actions taken by an organization or government. Similarly, website defacement may also be used as setup, or a precursor, for future attacks such as Drive-by Compromise.(Citation: Trend Micro Deep Dive Into Defacement)
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.
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.
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.