Debian dsa-5724 : 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-5724. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(201213);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/07/01");

  script_cve_id("CVE-2024-6387");

  script_name(english:"Debian dsa-5724 : openssh-client - 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 12 host has packages installed that are affected by a vulnerability as referenced in the dsa-5724
advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-5724-1                   [email protected]
    https://www.debian.org/security/                     Salvatore Bonaccorso
    July 01, 2024                         https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : openssh
    CVE ID         : CVE-2024-6387

    The Qualys Threat Research Unit (TRU) discovered that OpenSSH, an
    implementation of the SSH protocol suite, is prone to a signal handler
    race condition. If a client does not authenticate within LoginGraceTime
    seconds (120 by default), then sshd's SIGALRM handler is called
    asynchronously and calls various functions that are not
    async-signal-safe. A remote unauthenticated attacker can take advantage
    of this flaw to execute arbitrary code with root privileges. This flaw
    affects sshd in its default configuration.

    Details can be found in the Qualys advisory at
    https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt

    For the stable distribution (bookworm), this problem has been fixed in
    version 1:9.2p1-2+deb12u3.

    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 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/openssh");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2024-6387");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bookworm/openssh");
  script_set_attribute(attribute:"solution", value:
"Upgrade the openssh-client packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2024-6387");

  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:"2024/07/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/07/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/07/01");

  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-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-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:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2024 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]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 12.0', '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+deb12u3'},
    {'release': '12.0', 'prefix': 'openssh-client-udeb', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'openssh-server', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'openssh-server-udeb', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'openssh-sftp-server', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'openssh-tests', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'ssh', 'reference': '1:9.2p1-2+deb12u3'},
    {'release': '12.0', 'prefix': 'ssh-askpass-gnome', 'reference': '1:9.2p1-2+deb12u3'}
];

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-udeb / openssh-server / etc');
}