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Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Git vulnerability (USN-4761-1)

high Nessus Plugin ID 148010

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Synopsis

The remote Ubuntu host is missing a security update.

Description

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 20.10 host has packages installed that are affected by a vulnerability as referenced in the USN-4761-1 advisory.

 - Git is an open-source distributed revision control system. In affected versions of Git a specially crafted repository that contains symbolic links as well as files using a clean/smudge filter such as Git LFS, may cause just-checked out script to be executed while cloning onto a case-insensitive file system such as NTFS, HFS+ or APFS (i.e. the default file systems on Windows and macOS). Note that clean/smudge filters have to be configured for that. Git for Windows configures Git LFS by default, and is therefore vulnerable. The problem has been patched in the versions published on Tuesday, March 9th, 2021. As a workaound, if symbolic link support is disabled in Git (e.g. via `git config --global core.symlinks false`), the described attack won't work. Likewise, if no clean/smudge filters such as Git LFS are configured globally (i.e. _before_ cloning), the attack is foiled. As always, it is best to avoid cloning repositories from untrusted sources. The earliest impacted version is 2.14.2. The fix versions are:
 2.30.1, 2.29.3, 2.28.1, 2.27.1, 2.26.3, 2.25.5, 2.24.4, 2.23.4, 2.22.5, 2.21.4, 2.20.5, 2.19.6, 2.18.5, 2.17.62.17.6. (CVE-2021-21300)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-4761-1

Plugin Details

Severity: High

ID: 148010

File Name: ubuntu_USN-4761-1.nasl

Version: 1.5

Type: local

Agent: unix

Published: 3/23/2021

Updated: 10/16/2023

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Medium

Base Score: 5.1

Temporal Score: 4.2

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2021-21300

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:git-el, p-cpe:/a:canonical:ubuntu_linux:git-all, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:git-daemon-sysvinit, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:git, p-cpe:/a:canonical:ubuntu_linux:git-cvs, p-cpe:/a:canonical:ubuntu_linux:git-core, p-cpe:/a:canonical:ubuntu_linux:git-email, p-cpe:/a:canonical:ubuntu_linux:git-gui, p-cpe:/a:canonical:ubuntu_linux:git-daemon-run, p-cpe:/a:canonical:ubuntu_linux:git-svn, p-cpe:/a:canonical:ubuntu_linux:gitk, p-cpe:/a:canonical:ubuntu_linux:git-man, p-cpe:/a:canonical:ubuntu_linux:gitweb, p-cpe:/a:canonical:ubuntu_linux:git-arch, p-cpe:/a:canonical:ubuntu_linux:git-mediawiki

Required KB Items: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/9/2021

Vulnerability Publication Date: 3/9/2021

Exploitable With

Metasploit (Git LFS Clone Command Exec)

Reference Information

CVE: CVE-2021-21300

USN: 4761-1