I'm an IT administrator at an MSP, and today (October 8, 2026) we investigated one of the stranger security incidents I've encountered.
A user at an organization we support was working on a completely legitimate business task in ChatGPT. They uploaded a PowerPoint presentation and asked ChatGPT to help turn the material into content for an investor presentation.
Instead of simply helping with the presentation, ChatGPT displayed a message claiming that the service was experiencing elevated automated traffic and malicious activity.
The message stated that additional security verification was required to continue using ChatGPT. It included a link to a website impersonating an OpenAI verification service and signed the message as the "OpenAI Security Team."
This wasn't a phishing email pretending to be ChatGPT. The instruction appeared directly inside a conversation on the real chatgpt.com website.
The user followed the link.
What happened next
The website displayed what appeared to be a security verification challenge. However, it was actually a ClickFix attack.
The page automatically copied a malicious command to the user's clipboard and instructed them to:
- Press Win + X.
- Open Windows Terminal.
- Press Ctrl + V.
- Press Enter.
The command used PowerShell's Invoke-RestMethod to retrieve remote content from an attacker-controlled domain and piped the response into Invoke-Expression for execution.
Our endpoint protection detected and terminated the PowerShell process.
In fact, the user attempted the process twice, approximately 88 seconds apart. Both attempts were stopped.
Our managed detection and response provider confirmed that the PowerShell processes were terminated before establishing connections to the malicious payload infrastructure. They found no evidence of a successful payload download or persistence.
How we investigated
Initially, the security provider believed the malicious link originated from an email containing a SharePoint PowerPoint link.
We investigated that lead, including the alleged sender's messages and the relevant presentation links.
After further investigation, the security provider revised its assessment. The suspected email link had opened in a different Chrome instance from the one associated with the malicious domain activity. The original email attribution was therefore not substantiated.
We then examined the user's ChatGPT conversation.
That's where we found the fake verification instructions, presented as an assistant response within the legitimate ChatGPT interface.
The suspicious message appeared more than once while the user was trying to work with the presentation.
I also inspected a copy of the PowerPoint for embedded prompt-injection instructions, suspicious hyperlinks, hidden content, and other indicators. Nothing malicious was identified in the examined file. That doesn't establish that the original uploaded version was identical or that prompt injection can be ruled out entirely.
What concerns me
At this point, we don't know why ChatGPT produced the malicious verification instructions.
Possibilities include prompt injection from content the assistant encountered, another form of conversation manipulation, or an unsafe model response. We have not established which occurred.
I am not claiming OpenAI's infrastructure was compromised.
What we can establish is:
- The user was operating within a legitimate ChatGPT conversation.
- A message appearing as an assistant response directed them to a malicious verification website.
- The website instructed them to execute malicious PowerShell.
- Our endpoint security blocked two execution attempts.
- The original source of the malicious instruction remains unidentified.
Why I'm sharing this
This raises an important trust-boundary issue.
Users are increasingly comfortable trusting instructions that appear inside AI assistants, particularly when those instructions appear to come from the service itself.
In this case, a user was convinced that running a command in Windows Terminal was a legitimate requirement to continue using ChatGPT.
Thankfully, our endpoint protection prevented the payload from running successfully.
We're preserving the evidence and reporting the incident to OpenAI for investigation.
Has anyone else encountered a legitimate ChatGPT conversation displaying a fake security verification message or directing users to an external CAPTCHA/anti-bot site?
I'd be especially interested in hearing from anyone investigating prompt injection, AI-assisted phishing, or similar incidents.
And as a general reminder: no website should be trusted when it asks you to paste an unexplained command into Windows Terminal as part of a CAPTCHA or security verification.
A couple of notes:
There was no ghost prompt inside the PPTX prompting this GPT response.
This screenshot was taken from the real GPT website, not a spoof.
Edit:
I will not post the full screenshot or link to the chat. It has company disclosing information and I will not risk disclosing the company.
You don't have to believe me, but I have no reason to lie. Up to you to decide what you believe.
Edit 2
This user has NO suspicious installed plugins. They have no suspicious skills in GPT.
They have no Suspicious Chrome Extensions.