CVE-2021-32842 Information

Description

SharpZipLib (or ziplib) is a Zip GZip Tar and BZip2 library. Starting version 1.0.0 and 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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Reference

https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3 https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

LOW

Base Score

NONE

Base Severity

5.3