picoCTF Solutions

Tools / Strings Extractor

Strings Extractor

Drop a binary, library, image, or any other file and pull out every printable run of characters. This is the in-browser equivalent of the Unix strings command. Useful for reverse engineering, forensics, and the everyday CTF habit of “just run strings on it first.”

Drop any binary file here, or

Files never leave your browser. Limit 50 MiB.

How strings extraction works

A binary file is just bytes. Some of those bytes happen to encode text - hard-coded messages, format strings, error messages, library names, hash prefixes, embedded URLs. The strings algorithm is simple: walk the file and emit every run of printable characters at least N bytes long. The traditional default for N is 4 because shorter runs are mostly noise.

Bumping the minimum length filters out shorter junk strings; lowering it surfaces 2-3 character flags or short keys. Switching to UTF-16LE catches strings stored as wide characters - the default in Windows binaries. Try both encodings if a known string is missing from the ASCII view.

For CTF challenges, the workflow is usually:

  1. Identify the file type with the File Magic Identifier.
  2. Run strings here to look for hard-coded credentials or flags.
  3. Filter for picoCTF, flag, key, or http to find leaks.
  4. If nothing pops, switch to a disassembler ( ghidra, objdump, or radare2) to decode obfuscated values.

The flag-like highlighter looks for known prefixes ( picoCTF{, flag{) and credential-style patterns ( key=, password:). False positives happen, especially on large binaries, so use the filter to narrow down. For deeper analysis, pair this with the Hex Viewer to jump to the offset of an interesting string and see what surrounds it.

Challenges that use this tool