Yellowkey turns a stolen notebooks data into gold
This is a scary example of how quickly you can be impacted by a new vulnerability. News first broke publicly on 13 May, and within days we had a serious issue to deal with.
Most importantly, do not panic, but you must acknowledge that this is a VERY REAL problem.
YellowKey is a publicly released BitLocker bypass affecting Windows 11 and Windows Server 2022/2025 through the Windows Recovery Environment.
It appears most relevant to devices using default TPM-only BitLocker, although TPM plus PIN should be treated as a risk reduction step, not a magic force field.
Organisations should urgently review high-risk Windows 11 laptops, harden boot and recovery paths, consider TPM+PIN for sensitive devices, restrict USB boot, protect UEFI settings, and treat already stolen TPM-only affected devices as potential data exposure events rather than assuming BitLocker alone protected them.
Current public reporting says the published YellowKey proof of concept affects Windows 11 and Windows Server 2022/2025, and the published PoC has not been shown to work on Windows 10. That is NOT a reason to delay Windows 11. Unsupported Windows 10 devices are accumulating risk, and staying there is not a strategy.
There is a darkly funny side to this, if you lost your keys, YellowKey has apparently come to your rescue. But do not treat this as a recovery method but rather as a security incident.
YellowKey
I find the name for the bypass interesting. Yellow is sometimes associated with gold, and if that notebook contains customer data, HR files, legal documents, pricing models, credentials or confidential emails, the thief may have found the equivalent of the "pot of gold". If that Windows 11 device was protected only by standard TPM-based BitLocker, and it is still sitting somewhere with the data intact, it may have just become a lot more interesting to the wrong person.
What do I do? First, identify high-risk Windows 11 notebooks. Executives, finance, HR, legal, developers, administrators and anyone carrying sensitive data.
Then, check and implement the basics.
- BitLocker recovery keys backed up properly?
- TPM enabled?
- Secure Boot enabled?
- USB boot disabled where practical?
- BIOS/UEFI administrator password set? (be VERY careful here - get help for this)
- BitLocker TPM plus PIN applied to high-risk devices? (Check how with OEM)
- Windows patched?
- BIOS and firmware updated, but tested first?
- Intune, Defender for Endpoint, or your endpoint tool reporting the real device state?
For notebooks already stolen, the horse has bolted.
You can no longer assume encryption saved you. Confirm whether BitLocker was enabled, whether it was TPM-only or TPM plus PIN, whether Secure Boot was enabled, whether the device was compliant, and whether the recovery key was safely escrowed.
Then kill access.
Disable the device, revoke Microsoft 365 sessions, force a password reset, review MFA methods, block access through Conditional Access and check sign-in logs after the theft.
Remote wipe is useful only if the device comes online. If it stays offline, it will not wipe. That is not a strategy, that is a "wish with a Wi-Fi wand".
If sensitive data was on the device, escalate properly. Security, legal, compliance and the data protection officer need to decide whether this is just a stolen asset, or a reportable incident.
BitLocker still matters.
But the question has changed. It is no longer, “Was it encrypted?”. It is, “Can you prove it was protected well enough when it disappeared?”
Please contact your First Technology Group account manager to connect with our security and endpoint specialists to review BitLocker, Secure Boot, Intune compliance and stolen-device response before the next notebook turns into someone else’s goldmine.
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