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Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVE-2021-32842

Severity Medium
Score 5.3/10

Summary

SharpZipLib (or #ziplib) is a Zip, GZip, Tar and BZip2 library. Prior to version 1.3.3, a check was added if the destination file is under a destination directory. However, it is not enforced that `_baseDirectory` ends with slash. If the _baseDirectory is not slash terminated like `/home/user/dir` it is possible to create a file with a name thats begins as the destination directory one level up from the directory, i.e. `/home/user/dir.sh`. Because of the file name and destination directory constraints, the arbitrary file creation impact is limited and depends on the use case. Version 1.3.3 fixed this vulnerability.

  • LOW
  • NETWORK
  • LOW
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • NONE

CWE-22 - Path Traversal

Path traversal (or directory traversal), is a vulnerability that allows malicious users to traverse the server's root directory, gaining access to arbitrary files and folders such as application code & data, back-end credentials, and sensitive operating system files. In the worst-case scenario, an attacker could potentially execute arbitrary files on the server, resulting in a denial of service attack. Such an exploit may severely impact the integrity, confidentiality, and availability of an application.

Advisory Timeline

  • Published