Slack AI could be tricked into leaking private-channel data via indirect prompt injection
At a Glance
- Serious damage. Customer data affected, security incident, or financial losses $10k–$100k.
Independent project · aggregated from public reports and may be unverified — see the primary source below · not affiliated with or endorsed by any company or product named.
What Happened
PromptArmor disclosed in August 2024 that Slack AI could be manipulated through indirect prompt injection: an attacker posting in any public channel could plant instructions that, when a victim later queried Slack AI, caused it to render a markdown link exfiltrating private-channel content (such as secrets or API keys) to the attacker's server via the URL — without the attacker ever accessing the private data directly. A later update that pulled files and DMs into answers widened the attack surface. Slack deployed a patch.
Case Analysis
Verified Facts
- PromptArmor disclosed indirect prompt injection in Slack AI in Aug 2024
- An attacker needed only to post in a public channel
- Private-channel content could be exfiltrated via a rendered markdown link
- Slack deployed a patch
Not Publicly Confirmed
- Whether the technique was exploited in the wild
Operational Lessons
- Treat all retrieved content as untrusted input to the model
- Block model-rendered links that can carry data to arbitrary domains
Primary Source
Slack AI can leak private data via prompt injection (The Register)theregister.com ↗Case Record
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Prompt injection reached host-level code execution in Microsoft Semantic Kernel through eval() and a stray annotation
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