The software does not properly prevent access to, or detect usage of, alternate data streams (ADS). An attacker can use an ADS to hide information about a file (e.g. size, the name of the process) from a system or file browser tools such as Windows Explorer and 'dir' at the command line utility. Alternately, the attacker might be able to bypass intended access restrictions for the associated data fork. 631 699 Category ChildOf 68 1000 699 Weakness ChildOf 66 631 Category ChildOf 634 888 Category ChildOf 904 Alternate data streams (ADS) were first implemented in the Windows NT operating system to provide compatibility between NTFS and the Macintosh Hierarchical File System (HFS). In HFS, data and resource forks are used to store information about a file. The data fork provides information about the contents of the file while the resource fork stores metadata such as file type. Architecture and Design Implementation Access_Control Non-Repudiation Other Bypass protection mechanism Hide activities Other Testing Software tools are capable of finding ADSs on your system. Implementation Ensure that the source code correctly parses the filename to read or write to the correct stream. CVE-1999-0278 In IIS, remote attackers can obtain source code for ASP files by appending "::$DATA" to the URL. CVE-2000-0927 Product does not properly record file sizes if they are stored in alternative data streams, which allows users to bypass quota restrictions. This and similar problems exist because the same resource can have multiple identifiers that dictate which behavior can be performed on the resource. System Process Don Parker Windows NTFS Alternate Data Streams 2005-02-16 http://www.securityfocus.com/infocus/1822 M. Howard D. LeBlanc Writing Secure Code 2nd Edition Microsoft 2003 Windows ::DATA alternate data stream 11 168 PLOVER Eric Dalci Cigital 2008-07-01 updated Time_of_Introduction CWE Content Team MITRE 2008-09-08 updated Applicable_Platforms, Background_Details, Description, Relationships, Other_Notes, References, Taxonomy_Mappings CWE Content Team MITRE 2008-10-14 updated Description CWE Content Team MITRE 2009-10-29 updated Other_Notes, Theoretical_Notes CWE Content Team MITRE 2010-04-05 updated Related_Attack_Patterns CWE Content Team MITRE 2010-12-13 updated Name CWE Content Team MITRE 2011-06-01 updated Common_Consequences CWE Content Team MITRE 2012-05-11 updated Observed_Examples, References, Relationships CWE Content Team MITRE 2012-10-30 updated Potential_Mitigations Windows ::DATA Alternate Data Stream Failure to Handle Windows ::DATA Alternate Data Stream