By mounting different filesystem it's possible to mask file flagged 'immutable'. It's possible to rollback system tiime by setting it to maximum value.
vulners.com/securityvulns/securityvulns:doc:10939
vulners.com/securityvulns/securityvulns:doc:10940
vulners.com/securityvulns/securityvulns:doc:10951