Denial of AI Service - AI Security Technique

Researchers at Lumia have demonstrated that it is possible to extract authentication tokens from the memory of LLM Desktop Applications. An attacker could then use those tokens to impersonate as the victim to the LLM backed, thereby gaining access to the victim’s conversations as well as the ability to interfere in future conversations. The attacker’s access would allow them the ability to directly inject prompts to change the LLM’s behavior, poison the LLM’s context to have persistent effects, manipulate the user’s conversation history to cover their tracks, and ultimately impact the confidentiality, integrity, and availability of the system. The researchers demonstrated this on Anthropic Claude, Microsoft M365 Copilot, and OpenAI ChatGPT.

Vendor Responses to Responsible Disclosure:

• Anthropic (HackerOne) - Closed as informational since local attack.
• Microsoft Security Response Center - Attack doesn’t bypass security boundaries for CVE.
• OpenAI (BugCrowd) - Closed as informational and noted that it’s up to Microsoft to patch this behavior.

The publicly available Streamlit application MathGPT uses GPT-3, a large language model (LLM), to answer user-generated math questions.

Recent studies and experiments have shown that LLMs such as GPT-3 show poor performance when it comes to performing exact math directly^[1][2]. However, they can produce more accurate answers when asked to generate executable code that solves the question at hand. In the MathGPT application, GPT-3 is used to convert the user's natural language question into Python code that is then executed. After computation, the executed code and the answer are displayed to the user.

Some LLMs can be vulnerable to prompt injection attacks, where malicious user inputs cause the models to perform unexpected behavior^[3][4]. In this incident, the actor explored several prompt-override avenues, producing code that eventually led to the actor gaining access to the application host system's environment variables and the application's GPT-3 API key, as well as executing a denial of service attack. As a result, the actor could have exhausted the application's API query budget or brought down the application.

After disclosing the attack vectors and their results to the MathGPT and Streamlit teams, the teams took steps to mitigate the vulnerabilities, filtering on select prompts and rotating the API key.

References

1. [1] https://arxiv.org/abs/2103.03874
2. [2] https://arxiv.org/abs/2110.14168
3. [3] https://lspace.swyx.io/p/reverse-prompt-eng
4. [4] https://research.nccgroup.com/2022/12/05/exploring-prompt-injection-attacks/