Microsoft Recall Again Spills Secrets

Microsoft’s determination to embed the automatic screenshot storage and retrieval feature dubbed Recall into operating systems doesn’t appear matched by resolve to make it secure.

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For the second time, cybersecurity researcher Alexander Hagenah said he’s found vulnerabilities in Recall that allowed him to find where the features stores encrypted data and extract it all for easy review.

“I can’t comment on the current Recall issue or the specific technique I used, because I reported it to Microsoft and the case is currently being reviewed and reproduced,” Hagenah, a Zurich-based cybersecurity executive who does research in his spare time, told Information Security Media Group on Wednesday.

Whether Microsoft classifies the issue Hagenah identified as a vulnerability and issues a fix remains to be seen. Hagenah has promised to issue a full technical write-up once the vulnerability disclosure process is resolved.

Microsoft CEO Satya Nadella memorably described Recall as giving your Windows PC “photographic memory.” If activated, the optional Windows 11 feature takes “snapshots” – as in, screenshots – every few seconds or when content changes on the PC screen, then runs them through optical character recognition and saves the images and text in encrypted form on a user’s hard drive.

“Quickly find and jump back into what you have seen before on your PC,” using “an explorable timeline” as well as “semantic powered search,” meaning that “any photo, link, or message can be a fresh point to continue from,” Microsoft says.

Functionally speaking, the tool may store everything it sees – passwords, search histories, sites visited, payment card details, health records, cryptocurrency wallet access codes. Microsoft says it enables by default a “sensitive information filtering” setting meant to filter out that data.

Critics have been mostly unimpressed, likening Recall to infostealer malware planted by hackers and warning that the thriving market for stolen data is poised to take advantage of Recall’s presence on desktops across the globe. “Infostealer Trojans, which automatically steal usernames and passwords, are a major problem for well over a decade – now these can just be easily modified to support Recall,” wrote cybersecurity expert Kevin Beaumont in 2024, after Recall was first announced.

Hagenah first found an exploitable Recall flaw in mid-2024, when the feature was offered in “preview” mode. Hagenah released on GitHub a utility he dubbed TotalRecall – after the 1990 sci-fi action film – to demonstrate how the flaw could be exploited, to encourage Microsoft to better lock it down.

Dogged by these and other security and privacy concerns, Microsoft issued updated preview versions and delayed the public rollout of Recall for over a year (see: Breach Roundup: Microsoft Tries Again With Windows Recall).

In January, Windows Central reported that Microsoft was rethinking how it integrates artificial intelligence features into Windows, and that it might seek to further refine Recall, as well as rebrand the feature.

In recent weeks, Hagenah reviewed the latest version of Recall. He was able to update his utility, now dubbed “TotalRecall Reloaded,” to successfully inject a new type of payload into AIXHost.exe – the Windows 11 component that handles AI features and user interface elements, including for Recall – to successfully extract screenshots, thumbnails, OCR text and CSV metadata, according to a screenshot he posted to social platform X on March 6.

Hagenah said “Microsoft redesigned the entire architecture with VBS enclaves after the original TotalRecall,” although he was still able to pop “the new defenses.” Again, for now, he’s keeping the specifics under wraps.

Following on Hagenah’s post, Beaumont said he reviewed the current implementation of Recall and found that “yep, you can just read the database as a user process” in plaintext, and that “the database also contains all manner of fields which aren’t publicly disclosed for tracking the user’s activity.”

For any attacker able to gain access: “No AV or EDR alerts triggered, world’s #1 in infostealer,” he said.

Despite finding a new exploitable vulnerability in Recall allowing him to find and dump everything being stored, Hagenah isn’t a critic of the functionality itself.

“The redesigned Recall is a substantial improvement over the original, and Microsoft has made meaningful and important security enhancements,” he said.

This challenge remains: How to capture and store sometimes extremely sensitive data, make it easily searchable, as well as to ensure that it cannot be abused.

“Software of this complexity is never fully ‘solved’ from a security perspective,” Hagenah said.

“When a feature touches multiple components and likely involves several teams and engineering disciplines, achieving a fully streamlined security model becomes inherently more difficult. The more sensitive the feature, the higher the bar and the more valuable independent scrutiny becomes,” he said.