Regex that validates Active Directory default password complexity

Question

I have a list of passwords that I need to examine and determine if they meet the default 3 of 4 rule for AD.

Rule is contain 3 of the 4 following requirements: low

Answer 1

You will have to build up the regular expression like this:

rule = [ "[a-z]", "[A-Z]", "[0-9]", "[!@#$%\^\&\(\)\+=]" ]

regex = ""
first = true
for a in 0..3:
  for b in 0..3:
    if a == b: continue
    for c in 0..3:
      if a == c or b == c: continue
      if not first:
        regex += "|"
      regex += "(" + rule[a] + ".*" + rule[b] + ".*" + rule[c] + ")"
      first = false

I'm not sure if I escaped the special characters correctly. It's kind of dependant on the language/toolkit you're using.