clarify segregation mitigation (#208)

1_1_vulns/PromptInjection.md

@@ -25,7 +25,7 @@ Prompt injection vulnerabilities are possible due to the nature of LLMs, which d
 
 1. Enforce privilege control on LLM access to backend systems. Provide the LLM with its own API tokens for extensible functionality, such as plugins, data access, and function-level permissions. Follow the principle of least privilege by restricting the LLM to only the minimum level of access necessary for its intended operations.
 2. Implement human in the loop for extensible functionality. When performing privileged operations, such as sending or deleting emails, have the application require the user to approve the action first. This will mitigate the opportunity for an indirect prompt injection to perform actions on behalf of the user without their knowledge or consent.
-3. Segregate external content from user prompts. Separate and denote where untrusted content is being used to limit  their influence on user prompts. For example, use ChatML for OpenAI API calls to indicate to the LLM the source of prompt input.
+3. Clearly separate and label external or other untrusted content used in prompts passed to the LLM. This allows the model to distinguish influencers like user prompts versus unvalidated external sources. Segregating these input sources may limit the ability of malicious external content to manipulate or inject unintended behavior into the LLM's prompt interpretations. Note that this mitigation is prone to circumvention when used in isolation, so must be used in conjunction with other mitigations.
 4. Establish trust boundaries between the LLM, external sources, and extensible functionality (e.g., plugins or downstream functions). Treat the LLM as an untrusted user and maintain final user control on decision-making processes. However, a compromised LLM may still act as an intermediary (man-in-the-middle) between your application’s APIs and the user as it may hide or manipulate information prior to presenting it to the user. Highlight potentially untrustworthy responses visually to the user.
 
 ### Example Attack Scenarios