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Description

The software uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize ‘…’ (triple dot) sequences that can resolve to a location that is outside of that directory.

Modes of Introduction:

– Implementation

 

 

Related Weaknesses

CWE-23

 

Consequences

Confidentiality, Integrity: Read Files or Directories, Modify Files or Directories

 

Potential Mitigations

Phase: Implementation

Effectiveness: High

Description: 

Phase: Implementation

Description: 

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 References

  • CVE-2001-0480
    • read of arbitrary files and directories using GET or CD with “…” in Windows-based FTP server.
  • CVE-2002-0288
    • read files using “.” and Unicode-encoded “/” or “” characters in the URL.