While adding general comments is very useful, some programmers tend to leave important data, such as: filenames related to the web application, old links or links which were not meant to be browsed by users, old code fragments, etc. An attacker who finds these comments can map the application's structure and files, expose hidden parts of the site, and study the fragments of code to reverse engineer the application, which may help develop further attacks against the site. 1000 699 Weakness ChildOf 540 888 Category ChildOf 895 Implementation Confidentiality Read application data Distribution Remove comments which have sensitive information about the design/implementation of the application. Some of the comments may be exposed to the user and affect the security posture of the application. The following comment, embedded in a JSP, will be displayed in the resulting HTML output. HTML JSP <!-- FIXME: calling this with more than 30 args kills the JDBC server --> CVE-2007-6197 Version numbers and internal hostnames leaked in HTML comments. CVE-2007-4072 CMS places full pathname of server in HTML comment. CVE-2009-2431 blog software leaks real username in HTML comment. Anonymous Tool Vendor (under NDA) Sean Eidemiller Cigital 2008-07-01 added/updated demonstrative examples Eric Dalci Cigital 2008-07-01 updated Potential_Mitigations, Time_of_Introduction CWE Content Team MITRE 2008-09-08 updated Relationships, Taxonomy_Mappings CWE Content Team MITRE 2008-10-14 updated Description CWE Content Team MITRE 2009-03-10 updated Demonstrative_Examples CWE Content Team MITRE 2009-07-27 updated Observed_Examples, Taxonomy_Mappings CWE Content Team MITRE 2011-03-29 updated Name CWE Content Team MITRE 2011-06-01 updated Common_Consequences CWE Content Team MITRE 2012-05-11 updated Relationships CWE Content Team MITRE 2012-10-30 updated Potential_Mitigations Information Leak Through Comments