This Kindle hack started with a book file

A security researcher has demonstrated how a malicious ebook or audiobook file could compromise a Kindle device and expose Amazon account access. The attack, shown during a security conference in Europe and responsibly disclosed to Amazon in advance, highlights how everyday digital content can turn into a serious security threat.

A normal book download with unexpected consequences

A live security demonstration revealed how a single malicious book file could be used to compromise a Kindle device. The attack did not rely on fake emails, social engineering, or password theft. Instead, it began the same way many people read every day: by opening a book.

Once the file was processed by the Kindle, flaws in the device’s software made it possible to access sensitive session data. This data could then be used to take over an already logged-in Amazon account, bypassing traditional login protections.

For Kindle users, the takeaway was uncomfortable. Even trusted-looking content can become a security risk if device software is not properly protected.

Inside the Kindle exploit chain

The demonstration was conducted by Valentino Ricotta, an engineering analyst at Thales, who analyzed how different parts of the Kindle software interacted with downloaded content.

Vulnerability one: audiobook file parsing

The first issue involved custom code used to process audiobook files. By crafting a file with unexpected input, Ricotta was able to trigger a memory-handling error. These types of flaws are widely recognized in cybersecurity as dangerous because they can allow unintended code execution.

In simple terms, the Kindle trusted the file too much.

Vulnerability two: keyboard privileges

The second flaw targeted the Kindle’s onscreen keyboard. The keyboard component reportedly operated with broad system privileges and lacked strict access controls. When combined with the first bug, this allowed deeper access to the device’s internal data.

Together, the two issues made it possible to extract Amazon session cookies stored on the Kindle.

Why stolen session cookies are dangerous

Session cookies act as proof that a user is already authenticated. If attackers obtain them, they may be able to:

• Access an Amazon account without entering a password.

• View order history and saved addresses.

• Make unauthorized purchases.

• Change account settings.

This makes cookie theft particularly risky, even for users who rely on strong passwords or two-step verification.

Amazon fixed the issue before public disclosure

The vulnerabilities were reported to Amazon ahead of time. According to the disclosure details, Amazon released fixes before the demonstration took place and classified the issue as critical. Ricotta received a $20,000 bug bounty for the findings.

The incident shows how coordinated disclosure can reduce real-world harm while still surfacing important security lessons.

What Kindle users should do now

Although the specific flaws have been patched, security experts recommend ongoing precautions:

• Keep Kindle software updated and allow automatic updates.

• Avoid sideloading ebooks or audiobooks from unknown or untrusted sources.

• Enable two-step verification on Amazon accounts.

• Review account activity regularly for unusual behavior.

Anyone who frequently transfers files via USB or email should be especially cautious.

Why this matters beyond Kindle

This demonstration reflects a wider security trend. Content files are increasingly used as attack vectors, whether they are books, images, or audio files. Any device that processes complex formats can become a target if safeguards are weak.

For users, the safest habits remain basic but effective: update devices promptly and treat unfamiliar files with skepticism, even when they look harmless.

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