As artificial intelligence becomes part of daily workflows, attackers are exploring new ways to exploit its weaknesses. Recent research has revealed a method where seemingly harmless images uploaded to AI systems can conceal hidden instructions, tricking chatbots into performing actions without the user’s awareness.
How hidden commands emerge
The risk lies in how AI platforms process images. To reduce computing costs, most systems shrink images before analysis, a step known as downscaling. During this resizing, certain pixel patterns, deliberately placed by an attacker can form shapes or text that the model interprets as user input. While the original image looks ordinary to the human eye, the downscaled version quietly delivers instructions to the system.
This technique is not entirely new. Academic studies as early as 2020 suggested that scaling algorithms such as bicubic or bilinear resampling could be manipulated to reveal invisible content. What is new is the demonstration of this tactic against modern AI interfaces, proving that such attacks are practical rather than theoretical.
Why this matters
Multimodal systems, which handle both text and images, are increasingly connected to calendars, messaging apps, and workplace tools. A hidden prompt inside an uploaded image could, in theory, request access to private information or trigger actions without explicit permission. One test case showed that calendar data could be forwarded externally, illustrating the potential for identity theft or information leaks.
The real concern is scale. As organizations integrate AI assistants into daily operations, even one overlooked vulnerability could compromise sensitive communications or financial data. Because the manipulation happens inside the preprocessing stage, traditional defenses such as firewalls or antivirus tools are unlikely to detect it.
Building safer AI systems
Defending against this form of “prompt injection” requires layered strategies. For users, simple precautions include checking how an image looks after resizing and confirming any unusual system requests. For developers, stronger measures are necessary: restricting image dimensions, sanitizing inputs before models interpret them, requiring explicit confirmation for sensitive actions, and testing models against adversarial image samples.
Researchers stress that piecemeal fixes will not be enough. Only systematic design changes such as enforcing secure defaults and monitoring for hidden instructions can meaningfully reduce the risks.
Images are no longer guaranteed to be safe when processed by AI systems. As attackers learn to hide commands where only machines can read them, users and developers alike must treat every upload with caution. By prioritizing proactive defenses, the industry can limit these threats before they escalate into real-world breaches.
Slack, the popular communication platform used by businesses worldwide, has recently taken action to address a potential security flaw related to its AI features. The company has rolled out an update to fix the issue and reassured users that there is no evidence of unverified access to their data. This move follows reports from cybersecurity experts who identified a possible weakness in Slack's AI capabilities that could be exploited by malicious actors.
The security concern was first brought to attention by PromptArmor, a cybersecurity firm that specialises in identifying vulnerabilities in AI systems. The firm raised alarms over the potential misuse of Slack’s AI functions, particularly those involving ChatGPT. These AI tools were intended to improve user experience by summarising discussions and assisting with quick replies. However, PromptArmor warned that these features could also be manipulated to access private conversations through a method known as "prompt injection."
Prompt injection is a technique where an attacker tricks the AI into executing harmful commands that are hidden within seemingly harmless instructions. According to PromptArmor, this could allow unauthorised individuals to gain access to private messages and even conduct phishing attacks. The firm also noted that Slack's AI could potentially be coerced into revealing sensitive information, such as API keys, which could then be sent to external locations without the knowledge of the user.
PromptArmor outlined a scenario in which an attacker could create a public Slack channel and embed a malicious prompt within it. This prompt could instruct the AI to replace specific words with sensitive data, such as an API key, and send that information to an external site. Alarmingly, this type of attack could be executed without the attacker needing to be a part of the private channel where the sensitive data is stored.
Further complicating the issue, Slack’s AI has the ability to pull data from both file uploads and direct messages. This means that even private files could be at risk if the AI is manipulated using prompt injection techniques.
Upon receiving the report, Slack immediately began investigating the issue. The company confirmed that, under specific and rare circumstances, an attacker could use the AI to gather certain data from other users in the same workspace. To address this, Slack quickly deployed a patch designed to fix the vulnerability. The company also assured its users that, at this time, there is no evidence indicating any customer data has been compromised.
In its official communication, Slack emphasised the limited nature of the threat and the quick action taken to resolve it. The update is now in place, and the company continues to monitor the situation to prevent any future incidents.
There are potential risks that come with integrating AI into workplace tools that need to be construed well. While AI has many upsides, including improved efficiency and streamlined communication, it also opens up new opportunities for cyber threats. It is crucial for organisations using AI to remain vigilant and address any security concerns that arise promptly.
Slack’s quick response to this issue stresses upon how imperative it is to stay proactive in a rapidly changing digital world.