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Porting a WAGO PLC exploit with Claude Code cost Forescout $500 and eight hours

Vedere Labs did get Claude Code to move a working exploit onto a second WAGO controller, and the price of doing it puts a measurable ceiling under the pitch that AI now writes OT exploits at machine speed.

The Watch · Security desk

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Illustration accompanying Porting a WAGO PLC exploit with Claude Code cost Forescout $500 and eight hours
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What happened

  • Forescout's Vedere Labs got Anthropic's Claude to port a working PLC remote code execution exploit onto a second WAGO model, but only with heavy researcher oversight, hours of work and hundreds of dollars in API spend.
  • A follow-up session aimed at a command-and-control implant tested increasingly complex payloads until one wrote to flash-mapped memory and permanently bricked the test PLC.
  • Forescout put the final stage of remote code execution development alone at over $500 in API usage, spread across a single session that ran more than eight hours.

Why it matters

  • What it costs cost Anyone pricing attacker economics in OT now has a floor measured on real hardware: roughly $60 an hour in inference, plus a senior reverse engineer's time, per firmware family.
  • What it limits constraint Expert supervision remains the binding input on throughput, because the model needed a human to feed it firmware detail and reverse its wrong turns, so headcount sets the pace rather than API credit.
  • What's now possible capability The rapid second payload shows where scale would come from: understand one firmware family's memory behavior once, then mint variants for related devices at small marginal effort.
  • What it sets up precedent Forescout is asking readers to price a trend rather than this result, which makes the next port the test of whether required expert intervention is actually falling.

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More than $500 in API usage across a session of more than eight hours works out to roughly $60 an hour in inference spend [13][14], and that covers only the final stage of the port. A researcher sat with it the whole way, supplying firmware context and pulling the model off incorrect leads [7].

No new vulnerability came out of this. CVE-2021-31886 is a pre-authentication buffer overflow in the Nucleus FTP server that lets an unauthenticated attacker run arbitrary ARM shellcode, and Forescout already had a working exploit for the WAGO 750-852 [2]. What was being measured is the porting labor: moving that exploit to the related 750-831 [3]. Confirmation was fast. Given a terminal, Ghidra, reference files and the physical device [5], Claude Code combined live probing with static firmware analysis and produced a payload that crashed the controller [6]. Crashing a PLC is the cheap part. Controlled execution stalled until the team moved from Claude Sonnet 4.6 to Claude Opus 4.6 and instructed the model to ask for help whenever it was unsure about a firmware detail [8], after which it worked out why its injected code kept being erased before it could run [9]. Two working payloads followed within 12 minutes [10], about 2.5 percent of the eight-hour session [15].

For asset owners the follow-up session carries more weight than the port. Asked to build a command-and-control implant, the model tested progressively more complex payloads until one wrote into a region mapped to the PLC's flash memory and permanently bricked it [12]. An agent that escalates writes against a live controller will eventually take the asset out, which costs an intruder the foothold and hands the operator the loudest indicator available.

Forescout says plainly that the guiding researcher could have done the port without AI in less time, at lower cost, and with the PLC still alive, and argues the question worth tracking is what happens as the required expert intervention falls, because AI can lower the marginal cost of repeating the work across many related targets at once [16]. That is the claim to hold them to. On this run the compression landed on the step that was already cheap: generating more payloads after a human had understood the memory behavior. The experiment ran in the wake of the coordinated attacks on water-sector PLCs [4]. Against that backdrop, the figure to track per firmware family is how many times a human had to intervene.

What to watch

  • A second Forescout port against another WAGO model, and whether the $500 figure and the intervention count move.
  • Any water-sector PLC case where investigators find ported exploit code rather than reuse of the public 750-852 exploit.
  • Bricked controllers turning up as the residue of failed intrusions instead of clean code execution.

Clarity's read

What the record supports and how the coverage leans. The claims behind it follow.

Reality

Evidence50
Adoption12
Hype gap−10
Incentives55
Confidence55
Why these scores

Claim ledger

Ranked by verification strength, evidence, and original report placement.

  1. [1]

    Researchers at Forescout's Vedere Labs used Anthropic's Claude to port a working remote code execution exploit from one WAGO programmable logic controller to another, succeeding only after extensive researcher oversight, several hours of dedicated work, and hundreds of dollars in API costs.

    Reported SupportedView cited source
  2. [2]

    The starting point was a previously developed exploit for the WAGO 750-852 PLC based on CVE-2021-31886, a pre-authentication buffer overflow in the Nucleus FTP server that allows an unauthenticated attacker to execute arbitrary ARM shellcode on the targeted PLC.

    Reported SupportedView cited source
  3. [3]

    Forescout set out to adapt that exploit to a related but distinct model, the WAGO 750-831, and to see whether the AI could push the result further into a full command-and-control implant.

    Reported SupportedView cited source
  4. [4]

    The experiment was conducted in the wake of the recent attacks targeting PLCs in the water sector.

    Reported SupportedView cited source
  5. [5]

    The researchers used Claude Code, giving it access to a terminal, reference files, the reverse-engineering tool Ghidra, and the physical target device.

    Reported SupportedView cited source
  6. [6]

    The AI confirmed the vulnerability through a mix of live probing and static firmware analysis before generating a payload that crashed the PLC.

    Reported SupportedView cited source
  7. [7]

    Turning the crash into controlled code execution took far longer, and early attempts sent the AI chasing incorrect leads, requiring researchers to redirect its analysis and provide additional technical context.

    Reported SupportedView cited source
  8. [8]

    Progress stalled until the team switched from Claude Sonnet 4.6 to Claude Opus 4.6 and instructed the model to ask for help whenever it was uncertain about a firmware detail.

    Reported SupportedView cited source
  9. [9]

    The breakthrough came when the AI figured out why the injected code kept getting erased before it could run, then adjusted its approach to keep the payload intact.

    Reported SupportedView cited source
  10. [10]

    Once that obstacle was cleared, Claude produced two separate working payloads within 12 minutes.

    Reported SupportedView cited source
  11. [11]

    Forescout notes that the pattern of a difficult, time-consuming path to initial execution followed by rapid iteration afterward is what makes the cost of scaling this kind of work worth watching.

    Reported SupportedView cited source
  12. [12]

    In a new session aimed at developing a command-and-control implant, Claude tested increasingly complex payloads, and one wrote to a region mapped to the PLC's flash memory, permanently bricking the device.

    Reported SupportedView cited source
  13. [13]

    Forescout said the final stage of RCE development alone consumed over $500 in API usage across a session lasting more than eight hours.

    Reported SupportedView cited source
  14. [14]

    The stated spend implies an inference burn rate of roughly $60 per hour of session time, as a lower bound.

    Derived Supported
  15. [15]

    The 12 minutes in which two working payloads were produced is about 2.5 percent of the eight-hour session.

    Derived Supported
  16. [16]

    Forescout wrote that the researcher guiding the AI could have achieved the initial RCE port without AI in less time and at lower cost while keeping the PLC alive, adding that the more important question is what happens as the amount of expert intervention required continues to fall, and that AI has the potential to reduce the marginal cost of doing this work across many related targets at once.

    Reported Insufficient Source: Forescout Vedere Labs, quoted by SecurityWeekView cited source

Sources

3 independent publishers whose own reporting we read for this story.

  1. securityaffairs.com

    1 article · September 2, 2026

    $536 and 8 Hours: AI Learns to Attack a Different PLC
  2. securityweek.com

    1 article · September 1, 2026

    Experiment: Porting a PLC Exploit With AI Takes Hours and Hundreds of Dollars
  3. thehackernews.com

    2 articles · September 2, 2026

    Researchers Use Claude to Port Pre-Auth RCE Exploit From One PLC Model to Another

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