Amazon Linux 2 : flatpak (ALAS-2021-1625)

high Nessus Plugin ID 148337

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of flatpak installed on the remote host is prior to 1.0.9-10. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2021-1625 advisory.

- Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In Flatpack since version 0.9.4 and before version 1.10.2 has a vulnerability in the file forwarding feature which can be used by an attacker to gain access to files that would not ordinarily be allowed by the app's permissions. By putting the special tokens `@@` and/or `@@u` in the Exec field of a Flatpak app's .desktop file, a malicious app publisher can trick flatpak into behaving as though the user had chosen to open a target file with their Flatpak app, which automatically makes that file available to the Flatpak app. This is fixed in version 1.10.2. A minimal solution is the first commit `Disallow @@ and @@U usage in desktop files`. The follow-up commits `dir: Reserve the whole @@ prefix` and `dir: Refuse to export .desktop files with suspicious uses of @@ tokens` are recommended, but not strictly required. As a workaround, avoid installing Flatpak apps from untrusted sources, or check the contents of the exported `.desktop` files in `exports/share/applications/*.desktop` (typically `~/.local/share/flatpak/exports/share/applications/*.desktop` and `/var/lib/flatpak/exports/share/applications/*.desktop`) to make sure that literal filenames do not follow `@@` or `@@u`. (CVE-2021-21381)

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

Solution

Run 'yum update flatpak' to update your system.

Plugin Details

Severity: High

ID: 148337

File Name: al2_ALAS-2021-1625.nasl

Version: 1.2

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 4/6/2021

Updated: 4/6/2021

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

Risk Information

VPR

Risk Factor: High

Score: 7.1

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.3

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

CVSS Score Source: CVE-2021-21381

CVSS v3

Risk Factor: High

Base Score: 8.2

Temporal Score: 7.1

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:flatpak, p-cpe:/a:amazon:linux:flatpak-builder, p-cpe:/a:amazon:linux:flatpak-debuginfo, p-cpe:/a:amazon:linux:flatpak-devel, p-cpe:/a:amazon:linux:flatpak-libs, cpe:/o:amazon:linux:2

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/2/2021

Vulnerability Publication Date: 3/11/2021

Reference Information

CVE: CVE-2021-21381

ALAS: 2021-1625

Detections

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