Atlas / Skills / cyberstrikeus / T1491 Defacement

T1491 DefacementCAUTION

skills/cyberstrikeus/t1491-defacement

Agent skill by cyberstrikeus · agents · ai hacking · ai penetration testing · Audited 2026-10-18

⚑ Report / re-scan Source ↗

Open-source AI-powered offensive security harness for automated penetration testing.

Verdict

CAUTION

Grade

Trust score

89 /100

Version

18.1

Hosts

—

License

AGPL-3.0

Stars

3,185

Overview

Open-source AI-powered offensive security harness for automated penetration testing.

Read from source at commit eaf7d03223fcOBSERVED · 2026-10-18

What it tells the agent

The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: "T1491_defacement"
description: "Adversaries may modify visual content available internally or externally to an enterprise network, thus affecting the integrity of the original content."
category: "business-logic"
version: "18.1"
author: "cyberstrike-official"
tags:
  - mitre-attack
  - enterprise
  - t1491
  - impact
  - windows
  - iaas
  - linux
  - macos
  - esxi
technique_id: "T1491"
tactic: "impact"
all_tactics:
  - impact
platforms:
  - Windows
  - IaaS
  - Linux
  - macOS
  - ESXi
mitre_url: "https://attack.mitre.org/techniques/T1491"
tech_stack:
  - windows
  - cloud
  - linux
  - macos
  - esxi
cwe_ids:
  - CWE-400
chains_with:
  - T1491.001
  - T1491.002
prerequisites: []
severity_boost:
  T1491.001: "Chain with T1491.001 for deeper attack path"
  T1491.002: "Chain with T1491.002 for deeper attack path"
---

# T1491 Defacement

## High-Level Description

Adversaries may modify visual content available internally or externally to an enterprise network, thus affecting the integrity of the original content. Reasons for Defacement include delivering messaging, intimidation, or claiming (possibly false) credit for an intrusion. Disturbing or offensive images may be used as a part of Defacement in order to cause user discomfort, or to pressure compliance with accompanying messages.

## Kill Chain Phase

- Impact (TA0040)

**Platforms:** Windows, IaaS, Linux, macOS, ESXi

## What to Check

- [ ] Identify if Defacement technique is applicable to target environment
- [ ] Check Windows systems for indicators of Defacement
- [ ] Check IaaS systems for indicators of Defacement
- [ ] Check Linux systems for indicators of Defacement
- [ ] Verify mitigations are bypassed or absent (1 known mitigations)
- [ ] Assess detection coverage (1 detection strategies)

## How to Test

### Manual Testing

1. **Identify Attack Surface**: Determine if the target environment is susceptible to Defacement by examining the target platforms (Windows, IaaS, Linux).

2. **Assess Existing Defenses**: Review whether mitigations for T1491 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

3. **Execute Test**: Use tools and methods described in the MITRE ATT&CK page and external references below.

> **Note**: No Atomic Red Team tests available for this technique. See [Atomic Red Team GitHub](https://github.com/redcanaryco/atomic-red-team) for updates.

## Remediation Guide

### M1053 Data Backup

Consider implementing IT disaster recovery plans that contain procedures for taking regular data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and destroy the backups to prevent recovery.

## Detection

### Defacement via File and Web Content Modification Across Platforms

## Risk Assessment

| Finding                         | Severity | Impact |
| ------------------------------- | -------- | ------ |
| Defacement technique applicable | Low      | Impact |

## CWE Categories

| CWE ID  | Title                             |
| ------- | --------------------------------- |
| CWE-400 | Uncontrolled Resource Consumption |

## References

- [Atomic Red Team - T1491](https://github.com/redcanaryco/atomic-red-team/tree/master/atomics/T1491)
- [MITRE ATT&CK - T1491](https://attack.mitre.org/techniques/T1491)

Trust audit

CAUTIONgrade B · trust 89/100 Install with care. The audit found things worth knowing before you trust its output.

Layer	What it checks	Result
L0	Provenance & inventory	WARN
L1	Static analysis of the code	NA
L2	Instruction surface (what it tells the agent)	PASS
L3	Class-specific surface	PASS
L4	Behavioural (sandbox)	SKIPPED

What the source does

Filesystem: none-observed
Network: none-observed
Shell: none-observed
Dependencies: pinned
Secrets in source: none-found