Collected research
Fontleak: exfiltrating text using CSS and Ligatures
An attacker who can inject CSS loads a custom font whose ligature rules collapse a known prefix plus the next character into a single glyph of a distinct width, so a container query on a sibling element measures that width and fires a different image request per character. Chained imports and animations advance the index, exfiltrating page text at roughly a thousand characters a minute.
Record
- Researcher
- Dragos Albastroiu
- Published by
- adragos.ro
- Date
- Topic
- Other
In the archive
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This page is the archive's own catalogue record. The research is the work of Dragos Albastroiu, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on .