61
Phase: Implementation
Strategy = Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation
before being validated (CWE-180). Make sure that the application does not decode the same
input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by
introducing dangerous inputs after they have been checked.
Observed Examples
Reference Description
CVE-2002-0661 "\" not in denylist for web server, allowing path traversal attacks when the
server is run in Windows and other OSes.
https://www.cve.org/CVERecord?id=CVE-2002-0661
CVE-2002-0946 Arbitrary files may be read files via ..\ (dot dot) sequences in an HTTP request.
https://www.cve.org/CVERecord?id=CVE-2002-0946
CVE-2002-1042 Directory traversal vulnerability in search engine for web server allows remote
attackers to read arbitrary files via "..\" sequences in queries.
https://www.cve.org/CVERecord?id=CVE-2002-1042
CVE-2002-1209 Directory traversal vulnerability in FTP server allows remote attackers to read
arbitrary files via "..\" sequences in a GET request.
https://www.cve.org/CVERecord?id=CVE-2002-1209
CVE-2002-1178 Directory traversal vulnerability in servlet allows remote attackers to execute
arbitrary commands via "..\" sequences in an HTTP request.
https://www.cve.org/CVERecord?id=CVE-2002-1178
MemberOf Relationships
This MemberOf relationships table shows additional CWE Catgeories and Views that reference this
weakness as a member. This information is often useful in understanding where a weakness fits
within the context of external information sources.
Nature Type ID Name Page
MemberOf 981 SFP Secondary Cluster: Path Traversal 888 2409
MemberOf 1404 Comprehensive Categorization: File Handling 1400 2529
Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
PLOVER '..\filename' ('dot dot backslash')
Software Fault Patterns SFP16 Path Traversal
CWE-29: Path Traversal: '\..\filename'
Weakness ID : 29
Structure : Simple
Abstraction : Variant
Description
The product uses external input to construct a pathname that should be within a restricted
directory, but it does not properly neutralize '\..\filename' (leading backslash dot dot) sequences
that can resolve to a location that is outside of that directory.
Extended Description
This allows attackers to traverse the file system to access files or directories that are outside of the
restricted directory.
CWE Version 4.14
CWE-29: Path Traversal: '\..\filename'
CWE-29: Path Traversal: '\..\filename'