Unity Linux 20.1050e / 20.1060e / 20.1070-8ae / 20.1070e Security Update: rubygem-bundler (UTSA-2024-005586)

high Nessus Plugin ID 341252

Synopsis

The Unity Linux host is missing one or more security updates.

Description

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2024-005586 advisory.

`Bundler` is a package for managing application dependencies in Ruby. In `bundler` versions before 2.2.33, when working with untrusted and apparently harmless `Gemfile`'s, it is not expected that they lead to execution of external code, unless that's explicit in the ruby code inside the `Gemfile` itself. However, if the `Gemfile` includes `gem` entries that use the `git` option with invalid, but seemingly harmless, values with a leading dash, this can be false. To handle dependencies that come from a Git repository instead of a registry, Bundler uses various commands, such as `git clone`. These commands are being constructed using user input (e.g. the repository URL). When building the commands, Bundler versions before 2.2.33 correctly avoid Command Injection vulnerabilities by passing an array of arguments instead of a command string. However, there is the possibility that a user input starts with a dash (`-`) and is therefore treated as an optional argument instead of a positional one. This can lead to Code Execution because some of the commands have options that can be leveraged to run arbitrary executables. Since this value comes from the `Gemfile` file, it can contain any character, including a leading dash.

To exploit this vulnerability, an attacker has to craft a directory containing a `Gemfile` file that declares a dependency that is located in a Git repository. This dependency has to have a Git URL in the form of `-u./payload`. This URL will be used to construct a Git clone command but will be interpreted as the upload-pack argument. Then this directory needs to be shared with the victim, who then needs to run a command that evaluates the Gemfile, such as `bundle lock`, inside.

This vulnerability can lead to Arbitrary Code Execution, which could potentially lead to the takeover of the system. However, the exploitability is very low, because it requires a lot of user interaction.
Bundler 2.2.33 has patched this problem by inserting `--` as an argument before any positional arguments to those Git commands that were affected by this issue. Regardless of whether users can upgrade or not, they should review any untrustred `Gemfile`'s before running any `bundler` commands that may read them, since they can contain arbitrary ruby code.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

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 rubygem-bundler package.

Plugin Details

Severity: High

ID: 341252

File Name: unity_linux_UTSA-2024-005586.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 8/28/2026

Updated: 8/28/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.84

CVSS v2

Risk Factor: High

Base Score: 9.3

Temporal Score: 7.3

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

CVSS Score Source: CVE-2021-43809

CVSS v3

Risk Factor: High

Base Score: 7.3

Temporal Score: 6.6

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

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

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/8/2026

Vulnerability Publication Date: 12/8/2021

Reference Information

CVE: CVE-2021-43809

Detections

Analytics