Exim 4.92 < 4.92.3 RCE Vulnerability

# SPDX-FileCopyrightText: 2019 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:exim:exim";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.108654");
  script_version("2024-01-10T05:05:17+0000");
  script_tag(name:"last_modification", value:"2024-01-10 05:05:17 +0000 (Wed, 10 Jan 2024)");
  script_tag(name:"creation_date", value:"2019-07-29 06:24:44 +0000 (Mon, 29 Jul 2019)");
  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:"2020-08-18 15:05:00 +0000 (Tue, 18 Aug 2020)");

  script_xref(name:"CISA", value:"Known Exploited Vulnerability (KEV) catalog");
  script_xref(name:"URL", value:"https://www.cisa.gov/known-exploited-vulnerabilities-catalog");
  script_cve_id("CVE-2019-16928");

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

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

  script_name("Exim 4.92 < 4.92.3 RCE Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2019 Greenbone AG");
  script_family("General");
  script_dependencies("gb_exim_smtp_detect.nasl");
  script_mandatory_keys("exim/detected");

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

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

  script_tag(name:"insight", value:"There is a heap-based buffer overflow in string_vformat
  (string.c). The currently known exploit uses an extraordinary long EHLO string to crash the Exim
  process that is receiving the message. While at this mode of operation Exim already dropped its
  privileges, other paths to reach the vulnerable code may exist.");

  script_tag(name:"impact", value:"A local or remote attacker can execute programs.");

  script_tag(name:"affected", value:"Exim versions 4.92 through 4.92.2.");

  script_tag(name:"solution", value:"Update to version 4.92.3 or later.");

  script_xref(name:"URL", value:"https://exim.org/static/doc/security/CVE-2019-16928.txt");

  exit(0);
}

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

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

if (!version = get_app_version(cpe: CPE, port: port))
  exit(0);

if (version_in_range(version: version, test_version: "4.92", test_version2: "4.92.2")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.92.3");
  security_message(port: port, data: report);
  exit(0);
}

exit(99);