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Recovering saved macOS user passwords #

Users who have (inadvisedly) enabled automatic login often forget the password. It is merely encoded with an XOR cipher and stored in /etc/kcpassword.

A number of sites suggest this Ruby one-liner to recover it:

sudo ruby -e'key=[125,137,82,35,210,188,221,234,163,185,31];IO.read("/etc/kcpassword").bytes.each_with_index{|b,i|break if key.include?(b);print [b^key[i%key.size]].pack("U*")}'

However, only the first four characters were returned in my limited testing.

Joaquin Moreno Garijo's Python script, kcpass.py, did the trick:

  1. Copy /etc/kcpassword via target disk mode, single-user mode, etc.
  2. curl -O https://raw.githubusercontent.com/jjarava/mac-osx-forensics/master/kcpass.py
  3. chmod +x kcpass.py
  4. ./kcpass.py $(xxd -p /path/to/kcpassword)
        Kcpasswd: 0x09e03c5ab3ccad998dd66d1a89b165ae7e8912b851f8f0ff.
        Magic Xor: 0x7d895223d2bcddeaa3b91f.
        Used Magic Xor: 0x7d895223d2bcddeaa3b91f7d895223d2bcddeaa3b91f7d895223d2bcddeaa3b91f.
    
        The password is: "tinyapps.org".
    

See also:

/mac | Sep 07, 2017


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