The emergence of generative artificial intelligence services has produced a steady increase in what is typically referred to as “prompt injection” hacks, manipulating large language models through logic rather than exploiting traditional security vulnerabilities.

However, the difference between the two is starting to blend. The Synopsys Cybersecurity Research Center warns today of a new prompt injection that exploits a security vulnerability, rather than logic alone, to steal data. The vulnerability was found in EmailGPT, an application programming interface service and Google Chrome extension that assists users in writing emails inside Gmail using OpenAI’s GPT models.

EmailGPT uses an API service that has been found to allow a malicious actor to inject direct prompts and take over the service logic. Using the vulnerability, attackers can force the AI service to leak standard hard-coded systems prompts or execute unwanted prompts.

When engaging with EmailGPT, an attacker can submit a malicious prompt that requests harmful information and the system will respond by providing the requested data. The vulnerability can also be executed by anyone who has access to the service.

When exploited, the vulnerability can lead to intellectual property leakage, denial-of-service and direct financial loss through an attacker making repeated requests to the AI provider’s API, which are pay-per-use.

The vulnerability has a Common Vulnerability Scoring System score of 6.5, indicating a medium severity.

The Synopsys CyRC researchers reached out to the developers of EmailGPT before going public with the details, adhering to their responsible disclosure policy. The company had not responded to Synopsys as of the time of writing despite multiple attempts to obtain a response over a 90-day period.

When it comes to security issues such as those involving CVSS scores, there is usually some workaround or way to overcome the issue at hand. However, in this case, the researchers simply recommend immediately removing EmailGPT from any installations.

Image: EmailGPT