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PicoCTF Enhance! Writeup: Reading Hidden SVG Text with strings

A picoCTF Enhance! walkthrough showing how SVG files can expose readable text through strings and simple filtering.

Feb 11, 20242 min readAdapted from my picoCTF notes
PicoCTFForensicsSVGstrings

Enhance! is a picoCTF 2022 forensics challenge involving an SVG file. Since SVG is XML-based text, hidden or tiny rendered text can often be recovered without complex tooling.

SVG challenge preview

Extracting Text

I started with strings:

strings drawing.flag.svg

strings output

Then I filtered for SVG text-span closing tags to isolate useful fragments:

strings drawing.flag.svg | grep '</tspan>'

filtered output

Key Takeaways

  1. SVG files are text documents, so command-line text tools work well.
  2. strings is useful even when a file is not a traditional binary.
  3. Filtering around SVG tags can reduce noise quickly.