CVE-2021-43809 SUSE CVE security@suse.de SUSE Security Team SUSE CVE-2021-43809 Interim 1 35 2023-09-15T23:33:39Z current 2021-12-10T01:55:04Z 2023-09-15T23:33:39Z cve-database/bin/generate-cvrf-cve.pl 2020-12-27T01:00:00Z CVE-2021-43809 `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. The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). https://www.suse.com/support/security/rating/ SUSE Security Ratings SUSE CaaS Platform 4.0 SUSE Enterprise Storage 6 SUSE Enterprise Storage 7 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP5 SUSE Linux Enterprise High Availability Extension 12 SP4 SUSE Linux Enterprise High Availability Extension 12 SP5 SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP5 SUSE Linux Enterprise Server 15 SP1-LTSS SUSE Linux Enterprise Server 15 SP2-LTSS SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP5 SUSE Linux Enterprise Server for SAP Applications 12 SP4 SUSE Linux Enterprise Server for SAP Applications 12 SP5 SUSE Linux Enterprise Server for SAP Applications 15 SP1 SUSE Linux Enterprise Server for SAP Applications 15 SP2 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP5 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE OpenStack Cloud Crowbar 8 SUSE OpenStack Cloud Crowbar 9 ruby2.1-rubygem-bundler ruby2.5-rubygem-bundler rubygem-bundler ruby2.5-rubygem-bundler as a component of SUSE CaaS Platform 4.0 rubygem-bundler as a component of SUSE CaaS Platform 4.0 rubygem-bundler as a component of SUSE Enterprise Storage 6 rubygem-bundler as a component of SUSE Enterprise Storage 7 ruby2.1-rubygem-bundler as a component of SUSE Linux Enterprise High Availability Extension 12 SP4 rubygem-bundler as a component of SUSE Linux Enterprise High Availability Extension 12 SP4 ruby2.1-rubygem-bundler as a component of SUSE Linux Enterprise High Availability Extension 12 SP5 rubygem-bundler as a component of SUSE Linux Enterprise High Availability Extension 12 SP5 ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS rubygem-bundler as a component of SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS rubygem-bundler as a component of SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Module for Basesystem 15 SP4 rubygem-bundler as a component of SUSE Linux Enterprise Module for Basesystem 15 SP4 ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Module for Basesystem 15 SP5 rubygem-bundler as a component of SUSE Linux Enterprise Module for Basesystem 15 SP5 ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Server 15 SP1-LTSS rubygem-bundler as a component of SUSE Linux Enterprise Server 15 SP1-LTSS ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Server 15 SP2-LTSS rubygem-bundler as a component of SUSE Linux Enterprise Server 15 SP2-LTSS rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 12 SP4 rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 12 SP5 ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP1 rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP1 ruby2.5-rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP2 rubygem-bundler as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP2 ruby2.1-rubygem-bundler as a component of SUSE OpenStack Cloud Crowbar 8 rubygem-bundler as a component of SUSE OpenStack Cloud Crowbar 8 ruby2.1-rubygem-bundler as a component of SUSE OpenStack Cloud Crowbar 9 rubygem-bundler as a component of SUSE OpenStack Cloud Crowbar 9 `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. CVE-2021-43809 SUSE CaaS Platform 4.0:ruby2.5-rubygem-bundler SUSE CaaS Platform 4.0:rubygem-bundler SUSE Enterprise Storage 6:rubygem-bundler SUSE Enterprise Storage 7:rubygem-bundler SUSE Linux Enterprise High Availability Extension 12 SP4:ruby2.1-rubygem-bundler SUSE Linux Enterprise High Availability Extension 12 SP4:rubygem-bundler SUSE Linux Enterprise High Availability Extension 12 SP5:ruby2.1-rubygem-bundler SUSE Linux Enterprise High Availability Extension 12 SP5:rubygem-bundler SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS:ruby2.5-rubygem-bundler SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS:rubygem-bundler SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS:ruby2.5-rubygem-bundler SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS:rubygem-bundler SUSE Linux Enterprise Module for Basesystem 15 SP4:ruby2.5-rubygem-bundler SUSE Linux Enterprise Module for Basesystem 15 SP4:rubygem-bundler SUSE Linux Enterprise Module for Basesystem 15 SP5:ruby2.5-rubygem-bundler SUSE Linux Enterprise Module for Basesystem 15 SP5:rubygem-bundler SUSE Linux Enterprise Server 15 SP1-LTSS:ruby2.5-rubygem-bundler SUSE Linux Enterprise Server 15 SP1-LTSS:rubygem-bundler SUSE Linux Enterprise Server 15 SP2-LTSS:ruby2.5-rubygem-bundler SUSE Linux Enterprise Server 15 SP2-LTSS:rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 12 SP4:rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 12 SP5:rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 15 SP1:ruby2.5-rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 15 SP1:rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 15 SP2:ruby2.5-rubygem-bundler SUSE Linux Enterprise Server for SAP Applications 15 SP2:rubygem-bundler SUSE OpenStack Cloud Crowbar 8:ruby2.1-rubygem-bundler SUSE OpenStack Cloud Crowbar 8:rubygem-bundler SUSE OpenStack Cloud Crowbar 9:ruby2.1-rubygem-bundler SUSE OpenStack Cloud Crowbar 9:rubygem-bundler important 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H