{'fraction_non_alphanumeric': 0.026148969889064975, 'fraction_numerical': 0.006339144215530904, 'mean_word_length': 5.346733668341709, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Password Replacement Patterns

Enterprise password policies require the use of complex passwords that contain lowercase and uppercase letters, numbers and symbols. Considering this common requirement, end-users tend to create complex (!) passwords containing certain patterns which make such passwords guessable and therefore insecure. Replacement pattern is one of these pattern-types and substitutes a number or symbol for a certain letter. As an example, the letter “o” is replaced with 0 (zero) and password becomes password. Even though passw0rd contains a number and is assumed a strong password, its replacement pattern can be misused to guess it successfully and crack it easily. In our research, we performed an automated analysis of ca. 14.5 million real-life leaked passwords to identify all possible replacement patterns. We identified 43 different replacement-types at the end of the analysis. These identified replacement patterns can be utilized to improve dictionary-attacks, especially for forensic investigations. In this paper, we explain our methodology to identify replacement patterns, all possible replacement types with their examples, Top 5 replacement patterns with examples as well as the elimination of false-positive cases in detail.