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CVE-2021-37701 Detail

Current Description

The npm package "tar" (aka node-tar) before versions 4.4.16, 5.0.8, and 6.1.7 has an arbitrary file creation/overwrite and arbitrary code execution vulnerability. node-tar aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat calls to determine whether a given path is a directory, paths are cached when directories are created. This logic was insufficient when extracting tar files that contained both a directory and a symlink with the same name as the directory, where the symlink and directory names in the archive entry used backslashes as a path separator on posix systems. The cache checking logic used both `\` and `/` characters as path separators, however `\` is a valid filename character on posix systems. By first creating a directory, and then replacing that directory with a symlink, it was thus possible to bypass node-tar symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite. Additionally, a similar confusion could arise on case-insensitive filesystems. If a tar archive contained a directory at `FOO`, followed by a symbolic link named `foo`, then on case-insensitive file systems, the creation of the symbolic link would remove the directory from the filesystem, but _not_ from the internal directory cache, as it would not be treated as a cache hit. A subsequent file entry within the `FOO` directory would then be placed in the target of the symbolic link, thinking that the directory had already been created. These issues were addressed in releases 4.4.16, 5.0.8 and 6.1.7. The v3 branch of node-tar has been deprecated and did not receive patches for these issues. If you are still using a v3 release we recommend you update to a more recent version of node-tar. If this is not possible, a workaround is available in the referenced GHSA-9r2w-394v-53qc.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  8.6 HIGH
Vector:  CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  8.2 HIGH
Vector:  CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/npm/node-tar/security/advisories/GHSA-9r2w-394v-53qc Patch  Third Party Advisory 
https://www.debian.org/security/2021/dsa-5008 Third Party Advisory 
https://www.npmjs.com/package/tar Product  Third Party Advisory 
https://www.oracle.com/security-alerts/cpuoct2021.html Patch  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-59 Improper Link Resolution Before File Access ('Link Following') cwe source acceptance level NIST   Provider acceptance level GitHub, Inc.  
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') Provider acceptance level GitHub, Inc.  

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Change History

5 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-37701
NVD Published Date:
08/31/2021
NVD Last Modified:
12/03/2021
Source:
GitHub, Inc.