Developed for use with Microsoft Purview DLP, which uses the PCRE-compatible "Boost.Regex" engine for pattern matching.

Matches unformatted US Social Security number patterns (i.e. nine digits with no separators):

• Exclude all-zero area, group, or serial segment sequences:
  00XXXXXX, XXX00XXXX, or XXXXX0000
• Exclude group numbers 666 and 9##:
  666XXXXXX or 900XXXXXX
• Exclude ascending and descending number sequences:
  123456789, 876543210, etc.
• Excludes known retired SSNs:
  078051120 and 219099999
• Allows dash, em-dash, en-dash, space, slash, tab, and "null" separators
• Boundary checks to prevent matching on telephone, credit card, and other non-SSN types.
• Excludes sequences ending with common file extensions:
  .pdf, .doc(x), .xls(x), .ppt(x), .zip, .jp(e)g, .png, and .log

Derived from: Comprehensive US SSN (Social Security Number) Also uses patterns from the "U.S. Social Security Number (SSN) (Nucleuz Inc)" Sensitive Information Type contained in the Microsoft Purview DLP tool.