Debian dla-4615 : exim4 - security update

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory dla-4615. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(318796);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/05");

  script_cve_id("CVE-2026-48840");
  script_xref(name:"IAVA", value:"2026-A-0533");

  script_name(english:"Debian dla-4615 : exim4 - security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing a security-related update.");
  script_set_attribute(attribute:"description", value:
"The remote Debian 11 host has packages installed that are affected by a vulnerability as referenced in the dla-4615
advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4615-1                [email protected]
    https://www.debian.org/lts/security/                    Thorsten Alteholz
    June 05, 2026                                 https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : exim4
    Version        : 4.94.2-7+deb11u6
    CVE ID         : CVE-2026-48840


    Warisjeet Singh discovered that Exim, a mail transport agent, does not
    properly handle PROXY frames whose declared payload length is too short
    for the claimed address family, which may result in information
    disclosure in configurations with SUPPORT_PROXY and 'host_proxy' set.


    For Debian 11 bullseye, this problem has been fixed in version
    4.94.2-7+deb11u6.

    We recommend that you upgrade your exim4 packages.

    For the detailed security status of exim4 please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/exim4

    Further information about Debian LTS security advisories, how to apply
    these updates to your system and frequently asked questions can be
    found at: https://wiki.debian.org/LTS

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

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/source-package/exim4");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-48840");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bullseye/exim4");
  script_set_attribute(attribute:"solution", value:
"Upgrade the exim4 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-48840");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/05/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/05");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4-base");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4-config");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4-daemon-heavy");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4-daemon-light");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:exim4-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:eximon4");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Debian Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);

var debian_release = get_kb_item('Host/Debian/release');
if ( isnull(debian_release) ) audit(AUDIT_OS_NOT, 'Debian');
debian_release = chomp(debian_release);
if (! preg(pattern:"^(11)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 11.0', 'Debian ' + debian_release);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Debian', cpu);

var pkgs = [
    {'release': '11.0', 'prefix': 'exim4', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'exim4-base', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'exim4-config', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'exim4-daemon-heavy', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'exim4-daemon-light', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'exim4-dev', 'reference': '4.94.2-7+deb11u6'},
    {'release': '11.0', 'prefix': 'eximon4', 'reference': '4.94.2-7+deb11u6'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var _release = NULL;
  var prefix = NULL;
  var reference = NULL;
  if (!empty_or_null(package_array['release'])) _release = package_array['release'];
  if (!empty_or_null(package_array['prefix'])) prefix = package_array['prefix'];
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (_release && prefix && reference) {
    if (deb_check(release:_release, prefix:prefix, reference:reference)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : deb_report_get()
  );
  exit(0);
}
else
{
  var tested = deb_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'exim4 / exim4-base / exim4-config / exim4-daemon-heavy / etc');
}