fix: strip additional Unicode obfuscation vectors in sanitizer#1007
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qinlongli2024-ai wants to merge 1 commit intoanthropics:mainfrom
Open
fix: strip additional Unicode obfuscation vectors in sanitizer#1007qinlongli2024-ai wants to merge 1 commit intoanthropics:mainfrom
qinlongli2024-ai wants to merge 1 commit intoanthropics:mainfrom
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Extend stripInvisibleCharacters() to cover three additional Unicode ranges that can be used to smuggle hidden instructions or confuse code reviewers: - Tag characters (U+E0001–E007F): originally designed for emoji language tags, these can embed invisible ASCII-equivalent text in comments, issue bodies, or PR descriptions. - Variation selectors (U+FE00–FE0F): can alter glyph rendering to make visually identical characters differ at the codepoint level, enabling homoglyph / visual confusion attacks. - Interlinear annotation anchors (U+FFF9–FFFB): obscure formatting characters that have no visible rendering but could carry hidden payload in crafted inputs. Also adds descriptive comments to the existing stripping rules for better maintainability. Includes three new test cases covering each added range.
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Summary
stripInvisibleCharacters()insanitizer.tscovers zero-width characters, control characters, soft hyphens, and bidi overrides — but misses three additional Unicode ranges that can be used to smuggle hidden content through PR descriptions, issue bodies, and comments.Added coverage
Example attack
An attacker could include tag characters in a PR comment that are invisible to human reviewers but parsed by the LLM:
The visible part says "Looks good!" but the tag characters encode hidden instructions.
Changes
src/github/utils/sanitizer.ts: Add three new.replace()calls + descriptive comments on all existing rulestest/sanitizer.test.ts: Add three test cases for the new rangesChecklist