The Compression Bug That Rewrote Scanned Documents
In August twenty thirteen, German computer scientist David Kriesel discovered that certain Xerox copiers were silently swapping digits in scanned PDFs—turning a six into an eight on invoices and blueprints. This episode explores the JBIG2 compression flaw that made machines hallucinate numbers and why it remains a cautionary tale for digital forensics and document integrity.
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Xerox scanners silently swapped digits like six and eight while maintaining perfect visual clarity.
The JBIG2 compression standard prioritized small file sizes by building a dictionary of similar shapes.
Aggressive software thresholds caused machines to misidentify and substitute characters without leaving blurry artifacts.
David Kriesel proved these errors occurred at factory-default settings despite initial corporate denials.
Germany's Federal Office for Information Security classified JBIG2 compression as unsuitable for legal scanning.
Vulnerabilities in JBIG2 compression streams later enabled Pegasus spyware to execute zero-click attacks.
- 01Intro1 min
- 02The Discovery at the University of Bonn2 min
- 03The Mechanics of Hallucination2 min
- 04The Corporate and Regulatory Fallout2 min
- 05The Forensic and Security Legacy3 min
- 06Outro1 min
- Confused Xerox copiers rewrite scanned documents, ...
- Xerox Machines Change Documents After Scanning
- Xerox - Wikipedia
- The Role of Lossy Compression in Digital Image Forensics - ULB : Dok
- JBIG2
- JBIG2 – Wikipedia
- JBIG2-Komprimierung
- JBIG2 Compression Issue
- CVE-2015-6778 Detail - NVD
- KOST
- CVE-2017-3040 - Vulnerability Details - OpenCVE
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