Fedora 33 : git (2021-63fcbd126e) - Nessus

High Plugin ID: 147742

This page contains detailed information about the Fedora 33 : git (2021-63fcbd126e) Nessus plugin including available exploits and PoCs found on GitHub, in Metasploit or Exploit-DB for verifying of this vulnerability.

Table Of Contents

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Plugin Overview
Vulnerability Information

Synopsis
Description
Solution

Public Exploits
Risk Information
Plugin Source
How to Run
References
Version

Plugin Overview

ID: 147742
Name: Fedora 33 : git (2021-63fcbd126e)
Filename: fedora_2021-63fcbd126e.nasl
Vulnerability Published: 2021-03-09
This Plugin Published: 2021-03-12
Last Modification Time: 2022-01-21
Plugin Version: 1.5
Plugin Type: local
Plugin Family: Fedora Local Security Checks
Dependencies: ssh_get_info.nasl
Required KB Items [?]: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list

Vulnerability Information

Severity: High
Vulnerability Published: 2021-03-09
Patch Published: 2021-03-10
CVE [?]: CVE-2021-21300
CPE [?]: cpe:/o:fedoraproject:fedora:33, p-cpe:/a:fedoraproject:fedora:git

Synopsis

The remote Fedora host is missing one or more security updates.

Description

The remote Fedora 33 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-63fcbd126e 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 git package.

Public Exploits

Target Network Port(s): N/A
Target Asset(s): N/A
Exploit Available: True (Metasploit Framework, GitHub)
Exploit Ease: Exploits are available

Here's the list of publicly known exploits and PoCs for verifying the Fedora 33 : git (2021-63fcbd126e) vulnerability:

Metasploit: exploit/multi/http/git_lfs_clone_command_exec
[Git LFS Clone Command Exec]
GitHub: https://github.com/AlkenePan/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/CppXL/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/ETOCheney/cve-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/Faisal78123/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/Jiang59991/cve-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/Jiang59991/cve-2021-21300-plus
[CVE-2021-21300]
GitHub: https://github.com/Kirill89/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/Maskhe/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/Mochican/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/SexyBeast233/SecBooks
[CVE-2021-21300]
GitHub: https://github.com/bollwarm/SecToolSet
[CVE-2021-21300]
GitHub: https://github.com/danshuizhangyu/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/erranfenech/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/fengzhouc/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/tao-sun2/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/xiaofeihahah/CVE-2021-21300
[CVE-2021-21300]
GitHub: https://github.com/1uanWu/CVE-2021-21300
[CVE-2021-21300: Remote code exec for git]

Before running any exploit against any system, make sure you are authorized by the owner of the target system(s) to perform such activity. In any other case, this would be considered as an illegal activity.

WARNING: Beware of using unverified exploits from sources such as GitHub or Exploit-DB. These exploits and PoCs could contain malware. For more information, see how to use exploits safely.

Risk Information

CVSS Score Source [?]: CVE-2021-21300
CVSS V2 Vector: AV:N/AC:H/Au:N/C:P/I:P/A:P/E:F/RL:OF/RC:C

CVSS Base Score:	5.1 (Medium)
Impact Subscore:	6.4
Exploitability Subscore:	4.9
CVSS Temporal Score:	4.2 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	4.2 (Medium)

CVSS V3 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

CVSS Base Score:	7.5 (High)
Impact Subscore:	5.9
Exploitability Subscore:	1.6
CVSS Temporal Score:	7.0 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	7.0 (High)

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Plugin Source

##
# (C) Tenable Network Security, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2021-63fcbd126e
#

include('compat.inc');

if (description)
{
  script_id(147742);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/01/21");

  script_cve_id("CVE-2021-21300");
  script_xref(name:"FEDORA", value:"2021-63fcbd126e");

  script_name(english:"Fedora 33 : git (2021-63fcbd126e)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Fedora 33 host has a package installed that is affected by multiple vulnerabilities as referenced in the
FEDORA-2021-63fcbd126e 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.");
  script_set_attribute(attribute:"see_also", value:"https://bodhi.fedoraproject.org/updates/FEDORA-2021-63fcbd126e");
  script_set_attribute(attribute:"solution", value:
"Update the affected git package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-21300");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Git LFS Clone Command Exec');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/03/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:33");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:git");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Fedora Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include('audit.inc');
include('global_settings.inc');
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item('Host/RedHat/release');
if (isnull(release) || 'Fedora' >!< release) audit(AUDIT_OS_NOT, 'Fedora');
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
os_ver = os_ver[1];
if (! preg(pattern:"^33([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Fedora 33', 'Fedora ' + os_ver);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Fedora', cpu);

pkgs = [
    {'reference':'git-2.30.2-1.fc33', 'release':'FC33', 'rpm_spec_vers_cmp':TRUE}
];

flag = 0;
foreach package_array ( pkgs ) {
  reference = NULL;
  release = NULL;
  sp = NULL;
  cpu = NULL;
  el_string = NULL;
  rpm_spec_vers_cmp = NULL;
  epoch = NULL;
  allowmaj = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (reference && release) {
    if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'git');
}

The latest version of this script can be found in these locations depending on your platform:

Linux / Unix:
/opt/nessus/lib/nessus/plugins/fedora_2021-63fcbd126e.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\fedora_2021-63fcbd126e.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/fedora_2021-63fcbd126e.nasl

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How to Run

Here is how to run the Fedora 33 : git (2021-63fcbd126e) as a standalone plugin via the Nessus web user interface (https://localhost:8834/):

Click to start a New Scan.
Select Advanced Scan.
Navigate to the Plugins tab.
On the top right corner click to Disable All plugins.
On the left side table select Fedora Local Security Checks plugin family.
On the right side table select Fedora 33 : git (2021-63fcbd126e) plugin ID 147742.
Specify the target on the Settings tab and click to Save the scan.
Run the scan.

Here are a few examples of how to run the plugin in the command line. Note that the examples below demonstrate the usage on the Linux / Unix platform.

Basic usage:

/opt/nessus/bin/nasl fedora_2021-63fcbd126e.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a fedora_2021-63fcbd126e.nasl -t <IP/HOST>

Run the plugin with trace script execution written to the console (useful for debugging):

/opt/nessus/bin/nasl -T - fedora_2021-63fcbd126e.nasl -t <IP/HOST>

Run the plugin with using a state file for the target and updating it (useful for running multiple plugins on the target):

/opt/nessus/bin/nasl -K /tmp/state fedora_2021-63fcbd126e.nasl -t <IP/HOST>

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References

Fedora Security Update:

2021-63fcbd126e

See also:

Similar and related Nessus plugins:

148193 - Amazon Linux 2 : git (ALAS-2021-1621)
148131 - Amazon Linux AMI : git (ALAS-2021-1490)
149563 - EulerOS 2.0 SP8 : git (EulerOS-SA-2021-1870)
149540 - EulerOS 2.0 SP5 : git (EulerOS-SA-2021-1897)
150227 - EulerOS 2.0 SP9 : git (EulerOS-SA-2021-1923)
150179 - EulerOS 2.0 SP9 : git (EulerOS-SA-2021-1944)
151172 - EulerOS Virtualization for ARM 64 3.0.6.0 : git (EulerOS-SA-2021-1998)
151242 - EulerOS Virtualization 3.0.6.6 : git (EulerOS-SA-2021-2033)
156521 - EulerOS Virtualization 3.0.2.6 : git (EulerOS-SA-2021-2887)
147815 - Fedora 32 : git (2021-ffd0b2108d)
149221 - GLSA-202104-01 : Git: User-assisted execution of arbitrary code
152154 - openSUSE 15 Security Update : git (openSUSE-SU-2021:2555-1)
147799 - openSUSE Security Update : git (openSUSE-2021-405)
147825 - Photon OS 1.0: Git PHSA-2021-1.0-0369
147824 - Photon OS 2.0: Git PHSA-2021-2.0-0327
147821 - Photon OS 3.0: Git PHSA-2021-3.0-0207
148030 - Photon OS 4.0: Git PHSA-2021-4.0-0004
147737 - Slackware 14.0 / 14.1 / 14.2 / current : git (SSA:2021-070-01)
147749 - Security Updates for Microsoft Visual Studio Products (March 2021)
147436 - SUSE SLES12 Security Update : git (SUSE-SU-2021:0756-1)
147564 - SUSE SLED15 / SLES15 Security Update : git (SUSE-SU-2021:0757-1)
152157 - SUSE SLED15 / SLES15 Security Update : git (SUSE-SU-2021:2555-1)
148010 - Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 20.10 : Git vulnerability (USN-4761-1)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file fedora_2021-63fcbd126e.nasl version 1.5. For more plugins, visit the Nessus Plugin Library.

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Fedora 33 : git (2021-63fcbd126e) - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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