Agent Hijacking — Agent Hijacking Analysis

# **Agent Hijacking: The Evolving Threat of Malicious Tool and Session Manipulation** ## **Executive Summary** Agent hijacking is an increasingly sophisticated attack vector where adversaries manipulate automated systems, legitimate tools, or user sessions to execute unauthorized actions. This report examines three distinct manifestations of agent hijacking—**PayPal fraud via external transactions, tool hijacking in AI-driven architectures (e.g., MCP), and web session hijacking (SOUL Web Hijack)**—to highlight emerging attack patterns, technical mechanisms, and mitigation strategies. These threats underscore the need for **defense-in-depth security measures**, including strict input validation, runtime integrity monitoring, and session security hardening. --- ## **1. Agent Hijacking in Digital Payment Systems: PayPal Fraud via External Transactions** ### **Threat Landscape** PayPal remains a prime target for fraud due to its widespread adoption in peer-to-peer (P2P) and e-commerce transactions. A common attack vector involves **fraudulent sellers exploiting PayPal’s dispute resolution system** by receiving payment for goods (e.g., smartphones) via **Personal Payments** (outside eBay or other marketplaces) and then failing to deliver the item. #### **Attack Mechanics** 1. **Transaction Misrepresentation**: - The attacker lures the victim into sending money via **PayPal Friends & Family (P2P)** or **Goods & Services (G&S)** under the guise of a legitimate purchase. - The seller marks the