Discourse 2.8.x < 2.8.0.beta7 RCE Vulnerability

# SPDX-FileCopyrightText: 2021 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE = "cpe:/a:discourse:discourse";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.117756");
  script_version("2025-04-11T15:45:04+0000");
  script_tag(name:"last_modification", value:"2025-04-11 15:45:04 +0000 (Fri, 11 Apr 2025)");
  script_tag(name:"creation_date", value:"2021-10-26 13:26:20 +0000 (Tue, 26 Oct 2021)");
  script_tag(name:"cvss_base", value:"7.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-10-26 12:40:00 +0000 (Tue, 26 Oct 2021)");

  script_cve_id("CVE-2021-41163");

  script_tag(name:"qod_type", value:"remote_banner");

  script_tag(name:"solution_type", value:"VendorFix");

  script_name("Discourse 2.8.x < 2.8.0.beta7 RCE Vulnerability");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2021 Greenbone AG");
  script_family("Web application abuses");
  script_dependencies("gb_discourse_http_detect.nasl");
  script_mandatory_keys("discourse/detected");

  script_tag(name:"summary", value:"Discourse is prone to a remote code execution (RCE)
  vulnerability.");

  script_tag(name:"insight", value:"A validation bug in the upstream aws-sdk-sns gem can lead to RCE
  in Discourse via a maliciously crafted request.");

  script_tag(name:"affected", value:"Discourse version 2.8.0.beta1 through 2.8.0.beta6.");

  script_tag(name:"solution", value:"Update to version 2.8.0.beta7 or later.

  To workaround the issue without updating, requests with a path starting /webhooks/aws could be
  blocked at an upstream proxy.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_xref(name:"URL", value:"https://meta.discourse.org/t/2-8-0-beta7-security-release-fast-edits-topic-bookmarks-and-more/206578");
  script_xref(name:"URL", value:"https://github.com/discourse/discourse/security/advisories/GHSA-jcjx-pvpc-qgwq");
  script_xref(name:"URL", value:"https://0day.click/recipe/discourse-sns-rce/");
  script_xref(name:"URL", value:"https://github.com/discourse/discourse/pull/14671");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if (!port = get_app_port(cpe: CPE))
  exit(0);

if (!infos = get_app_version_and_location(cpe: CPE, port: port, exit_no_version: TRUE))
  exit(0);

version = infos["version"];
location = infos["location"];

if (version_in_range(version: version, test_version: "2.8.0.beta1", test_version2: "2.8.0.beta6")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "2.8.0.beta7", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);