Debian dsa-6204 : openssh-client - security update

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory dsa-6204. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(307671);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/21");

  script_cve_id("CVE-2025-61984", "CVE-2025-61985", "CVE-2026-3497");
  script_xref(name:"IAVA", value:"2025-A-0729-S");
  script_xref(name:"IAVA", value:"2025-A-0806-S");

  script_name(english:"Debian dsa-6204 : openssh-client - security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing one or more security-related updates.");
  script_set_attribute(attribute:"description", value:
"The remote Debian 12 / 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dsa-6204 advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6204-1                   [email protected]
    https://www.debian.org/security/                     Salvatore Bonaccorso
    April 09, 2026                        https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : openssh
    CVE ID         : CVE-2026-3497
    Debian Bug     : 1130595

    Jeremy Brown discovered a flaw in the GSSAPI Key Exchange patch applied
    in Debian to OpenSSH, an implementation of the SSH protocol suite,
    affecting non-default configurations with the GSSAPIKeyExchange setting
    enabled. A remote attacker can take advantage of this flaw to cause a
    denial of service, or potentially the execution of arbitrary code.

    For the oldstable distribution (bookworm), this problem has been fixed
    in version 1:9.2p1-2+deb12u9. This update includes fixes for
    CVE-2025-61984 and CVE-2025-61985 which were queued for the Debian
    bookworm 12.14 point release.

    For the stable distribution (trixie), this problem has been fixed in
    version 1:10.0p1-7+deb13u2.

    We recommend that you upgrade your openssh packages.

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

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

    Mailing list: [email protected]

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

Note that Nessus has not tested for these issues 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/openssh");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-61984");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-61985");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-3497");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bookworm/openssh");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/trixie/openssh");
  script_set_attribute(attribute:"solution", value:
"Upgrade the openssh-client packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-3497");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2025-61985");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/10/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-client-gssapi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-client-udeb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-server-gssapi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-server-udeb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-sftp-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh-tests");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ssh-askpass-gnome");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  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:"^(12)\.[0-9]+|^(13)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 12.0 / 13.0', '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': '12.0', 'prefix': 'openssh-client', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'openssh-client-udeb', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'openssh-server', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'openssh-server-udeb', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'openssh-sftp-server', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'openssh-tests', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'ssh', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '12.0', 'prefix': 'ssh-askpass-gnome', 'reference': '1:9.2p1-2+deb12u9'},
    {'release': '13.0', 'prefix': 'openssh-client', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-client-gssapi', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-client-udeb', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-server', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-server-gssapi', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-server-udeb', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-sftp-server', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'openssh-tests', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'ssh', 'reference': '1:10.0p1-7+deb13u2'},
    {'release': '13.0', 'prefix': 'ssh-askpass-gnome', 'reference': '1:10.0p1-7+deb13u2'}
];

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_HOLE,
    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, 'openssh-client / openssh-client-gssapi / openssh-client-udeb / etc');
}