---
id: 1404
title: "Deceiving users with ANSI terminal codes in MCP"
source_domain: blog.trailofbits.com
source_url: "https://blog.trailofbits.com/2025/04/29/deceiving-users-with-ansi-terminal-codes-in-mcp/"
published_at: "2025-04-29 13:00"
tags: ["ai-security", "claude-code", "mcp", "prompt-injection", "llm-security", "trail-of-bits", "ansi-escape-codes", "terminal-security"]
phying_url: "https://phying.com/item/1404"
lang: en
---

# Deceiving users with ANSI terminal codes in MCP

## Summary

Trail of Bits shows how ANSI escape sequences in MCP tool descriptions hide line-jumping payloads from users; Claude Code v0.2.76 does no filtering, enabling stealthy prompt injection attacks.

## Intelligence Metadata

- **Sources:** blog.trailofbits.com
- **Published:** 2025-04-29 13:00
- **Original:** https://blog.trailofbits.com/2025/04/29/deceiving-users-with-ansi-terminal-codes-in-mcp/
- **Phying News:** https://phying.com/item/1404