Rules File Backdoor is a new attack targeting AI-powered code editors. It silently injects malicious code into projects by corrupting the tools developers rely on.
This threat affects popular AI tools such as Copilot and Cursor. These editors use configuration or “rules” files to guide their code suggestions. However, attackers can secretly poison these files to manipulate the AI.
By using invisible characters and crafted prompts, attackers trick AI tools into generating code with hidden vulnerabilities. For example, the backdoor may use zero-width spaces or bidirectional markers that go unnoticed in standard reviews.
Therefore, the AI unknowingly assists in building malicious code. Developers might accept and commit this code, unaware of the risk. This creates a dangerous supply chain issue that can spread across multiple projects.
Moreover, if one poisoned file enters a shared repository, the threat escalates. Every contributor using AI tools becomes vulnerable, and malicious code can appear in every code generation session.
Another concern is that the poisoned files can survive forks and code merges. As a result, the malicious behavior passes down to other teams and even end users. This makes the attack long-lasting and hard to detect.
Reports show that this method bypasses standard reviews, even when teams use strict security practices. Attackers rely on the AI’s natural language understanding, tricking it into behaving in unsafe ways.
Although the tools’ providers state that users must review suggestions, the attack is subtle. Many developers trust their AI assistants, which makes this tactic even more effective.
How to Stay Safe from This Threat
To reduce the risk, developers must treat AI-generated code with skepticism. Always review suggestions manually, especially when using shared or unfamiliar rules files.
Use secure repositories, monitor for hidden characters in configuration files, and scan for known threat patterns. Additionally, educate teams about AI abuse risks and maintain strict code audit policies.
By taking proactive steps, you can protect your software supply chain and reduce the chance of hidden backdoors compromising your systems.
Sleep well, we got you covered.
