Details have recently surfaced about a now-patched vulnerability in Microsoft 365 Copilot that could have enabled the theft of sensitive user information through a technique called ASCII smuggling.
“ASCII Smuggling is a novel technique that uses special Unicode characters that resemble ASCII but are not actually visible in the user interface,” explained security researcher Johann Rehberger.
This technique is particularly concerning because it allows attackers to render invisible data within clickable hyperlinks, effectively staging it for exfiltration without the user’s knowledge.
Cybersecurity Threats in AI Tools
The attack in question cleverly combines several methods to form a reliable exploit chain. Here’s how the attack would unfold:
- Prompt Injection via Malicious Content: The attacker conceals malicious content within a document and shares it through chat, triggering a prompt injection.
- Instructing Copilot: The injected prompt then directs Copilot to search for more emails and documents containing sensitive information.
- ASCII Smuggling for Data Exfiltration: Finally, the attacker uses ASCII smuggling to entice the user into clicking on a link that exfiltrates the valuable data to a third-party server.
The ultimate outcome of this attack could be the transmission of sensitive data, such as multi-factor authentication (MFA) codes, to an adversary-controlled server. Fortunately, Microsoft addressed this vulnerability after it was responsibly disclosed in January 2024.
The Importance of Monitoring AI Tools
As artificial intelligence (AI) tools like Microsoft Copilot become more integrated into business operations, the risks associated with them must be carefully monitored. Proof-of-concept (PoC) attacks have demonstrated how malicious actors can manipulate AI tools to exfiltrate private data, bypass security measures, and even execute remote code.
At Impress Computers, we understand the evolving landscape of cybersecurity threats, particularly those emerging from AI-driven applications. These threats are not hypothetical; they are real and growing. Techniques like retrieval-augmented generation (RAG) poisoning and indirect prompt injection have shown that attackers can potentially gain full control over AI apps like Microsoft Copilot, even turning them into spear-phishing machines.
In one novel attack scenario, an external hacker with code execution capabilities could trick Copilot into providing users with phishing pages, mimicking the style of the compromised user to launch a targeted phishing attack.
Protecting Your Business with Impress Computers
Microsoft has acknowledged the risks associated with publicly exposed Copilot bots, especially those created using Microsoft Copilot Studio without adequate authentication protections. These vulnerabilities could be exploited by threat actors to extract sensitive information if they have prior knowledge of the bot’s name or URL.
At Impress Computers, we recommend that enterprises assess their risk tolerance and exposure to potential data leaks from AI tools like Copilot. It’s essential to enable Data Loss Prevention (DLP) and other security controls to manage the creation and publication of these AI tools securely.
By partnering with Impress Computers, businesses can ensure that they are equipped with the latest cybersecurity measures to protect against these emerging threats. Our team stays ahead of the curve, continuously monitoring for vulnerabilities and implementing robust security strategies tailored to your specific needs.
Don’t let your business fall victim to these sophisticated cyber threats. Trust Impress Computers to safeguard your digital assets in this rapidly changing technological landscape.
Cyber Incident Prevention Best Practices For
Your Small Business