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Advanced Topics –
Character Encoding
• What is a dot?
•
• Double dot sequences are recognized and rejected (by web server, IDS, application).
–A dot is a dot, e.g. /app/../admin/shutdown
–URL encoded, it is /app/%2e%2e/admin/shutdown
–IIS extension: /app/%u002e%u002e/admin/shutdown
–Double encoded: /app/%252e%252e/admin/shutdown
–UTF-8 overlong (2 bytes), un-URL-encoded:
– /app/(C0)(AE)(C0)(AE)/admin/shutdown
–UTF-8 overlong (2bytes), URL-encoded:
– /app/%c0%ae%c0%ae/admin/shutdown
–
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