I run a small MSP and recently ran into a situation that really highlights how strange and problematic Microsoft’s current
BitLocker/YellowKey situation is for real‑world businesses.
This was for a
potential new client, not an existing one—a very small business with no domain, no Entra/AD, and no centralized management. All their machines were essentially standalone devices with no tenant or account structure to tie them back to or manage.
They had a departing employee who had signed into their
company‑owned Windows 11 laptop using their
personal Microsoft account. That automatically enabled BitLocker and tied the recovery key to the employee’s personal account, not to the organization. When the employee left, they refused to provide the password or recovery key, effectively locking the company out of its own data. At the time, I had to tell them there was nothing I could do through normal, supported channels.
After the incident, I heard about the YellowKey BitLocker bypass PoC. I reached back out to see if they still had the laptop, and they did. With their authorization, I pulled the code from GitHub, built a Windows 11 install/recovery USB per the instructions, and tested it against that machine. Booting with that setup dropped me to a command prompt with full access to the C: drive. From there, I was able to copy off a set of critical files so they could recover some of their data.
In this particular case, YellowKey actually
helped the small business: without it, their data was effectively held hostage by a former employee’s personal Microsoft account, despite the company owning the hardware and having every right to the work product.
Since I already had that level of access, I decided to see if I could restore full, interactive use of the system. I used the classic cmd.exe ↔ utilman.exe swap at the logon screen (via the command prompt I already had), removed the boot media, and rebooted. Clicking the accessibility icon on the Windows logon screen then opened a command prompt with full admin rights in the live OS. From there I:
- Reactivated the built‑in Administrator account
- Reset its password to blank
- Rebooted and logged in as Administrator with no password
Once I had a working local admin session, I used
ForensiT Profile Wizard to migrate the former user’s profile onto a new account (in this case, I mapped it onto the Administrator profile). After another reboot and login as Administrator, I effectively had that user’s local profile, data, and configuration available inside the Administrator account.
There were, however, clear limits: anything that had
only ever lived in the user’s OneDrive cloud and was not fully synced locally was still inaccessible. For example, I could see image thumbnails that had been cached locally, but not the full‑resolution photos because those were only in the user’s personal Microsoft/OneDrive account.
For context, I’ve been a longtime user of
SpinRite and Steve’s
DNS Benchmark, so I’m very comfortable with low‑level disk recovery and diagnostics. This experience was a different kind of eye‑opener: not about failing hardware, but about how identity‑tied encryption on unmanaged corporate hardware can both lock out legitimate owners
and, at the same time, be undermined by something like YellowKey.
One thing this also made me think about: all the Windows 11 laptops that have been
lost or stolen over the last few years and are still running vulnerable builds are now essentially wide open. Those devices are never going to get patched, and as long as someone has a current Windows 11 install USB and a working copy of YellowKey, there’s very little to stop them from getting into the data on those machines. For those offline, non‑updating devices, no future Microsoft patch can retroactively protect them once they’re out in the wild.
And from a compliance and legal perspective, that means a lot of “we’re safe because the drive is BitLocker‑encrypted” incidents need to be revisited. If a Windows 11 laptop with regulated or sensitive data (PII, PHI, financials, etc.) is lost or stolen and known to be vulnerable to YellowKey, organizations may
no longer be able to treat it as securely encrypted media. In many jurisdictions and under many data‑protection regimes, that pushes those events much closer to being
reportable breaches of PII, not “no‑risk” losses.
I’m curious how others here are handling:
- Policies to forbid or technically block personal Microsoft accounts on corporate devices
- Standard procedures for escrow of BitLocker recovery keys in small, non‑domain environments
- Whether anyone is treating YellowKey (and similar bypasses) as an IR‑only tool of last resort, or leaning on it in edge cases like this where policy and reality collide
github.com
