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CWE-57

Path Equivalence: 'fakedir/../realdir/filename'

Variant
Incomplete

Description

The product contains protection mechanisms to restrict access to 'realdir/filename', but it constructs pathnames using external input in the form of 'fakedir/../realdir/filename' that are not handled by those mechanisms. This allows attackers to perform unauthorized actions against the targeted file.

Common Consequences

Scope

Confidentiality
Integrity

Impact

Read Files or Directories, Modify Files or Directories

Potential Mitigations

Implementation

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.

CVE-2001-1152

Proxy allows remote attackers to bypass denylist restrictions and connect to unauthorized web servers by modifying the requested URL, including (1) a // (double slash), (2) a /SUBDIR/.. where the desired file is in the parentdir, (3) a /./, or (4) URL-encoded characters.

CVE-2000-0191

application check access for restricted URL before canonicalization

CVE-2005-1366

CGI source disclosure using "dirname/../cgi-bin"

Applicable Platforms

Not Language-Specific

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