Debian dla-4716 : libruby2.7 - 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-4716. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(331823);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/04");

  script_cve_id(
    "CVE-2025-24294",
    "CVE-2025-61594",
    "CVE-2026-27820",
    "CVE-2026-41316"
  );

  script_name(english:"Debian dla-4716 : libruby2.7 - 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 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dla-4716 advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4716-1                [email protected]
    https://www.debian.org/lts/security/                          Abhijith PA
    August 04, 2026                               https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : ruby2.7
    Version        : 2.7.4-1+deb11u6 $bookworm_VERSION
    CVE ID         : CVE-2025-24294 CVE-2025-61594 CVE-2026-27820
                     CVE-2026-41316


    Ruby a popular language was affected by multiple vulnerabilities

    CVE-2025-24294

        The vulnerability is caused by an insufficient check on the length
        of a decompressed domain name within a DNS packet. An attacker can
        craft a malicious DNS packet containing a highly compressed domain
        name. When the resolv library parses such a packet, the name
        decompression process consumes a large amount of CPU resources, as
        the library does not limit the resulting length of the name. This
        resource consumption can cause the application thread to become
        unresponsive, resulting in a Denial of Service condition.

    CVE-2025-61594

         Using the + operator to combine URIs, sensitive information like
         passwords from the original URI can be leaked, violating RFC3986
         and making applications vulnerable to credential exposure. URI is
         a module providing classes to handle Uniform Resource
         Identifiers.

    CVE-2026-27820

        A buffer overflow vulnerability in the Zlib::GzipReader. The
        zstream_buffer_ungets function prepends caller-provided bytes
        ahead of previously produced output but fails to guarantee the
        backing Ruby string has enough capacity before the memmove shifts
        the existing data. This can lead to memory corruption when the
        buffer length exceeds capacity.

    CVE-2026-41316

        A deserialization vulnerability exists in ERB. Any Ruby
        application that calls Marshal.load on untrusted data AND has both
        erb and activesupport loaded is vulnerable to arbitrary code
        execution.

    For Debian 11 bullseye, these problems have been fixed in version
    2.7.4-1+deb11u6.

    We recommend that you upgrade your ruby2.7 packages.

    For the detailed security status of ruby2.7 please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/ruby2.7

    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 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/ruby2.7");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-24294");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-61594");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27820");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-41316");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bullseye/ruby2.7");
  script_set_attribute(attribute:"solution", value:
"Upgrade the libruby2.7 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  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:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-27820");

  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:"2025/07/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/04");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libruby2.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ruby2.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ruby2.7-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ruby2.7-doc");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  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) 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': 'libruby2.7', 'reference': '2.7.4-1+deb11u6'},
    {'release': '11.0', 'prefix': 'ruby2.7', 'reference': '2.7.4-1+deb11u6'},
    {'release': '11.0', 'prefix': 'ruby2.7-dev', 'reference': '2.7.4-1+deb11u6'},
    {'release': '11.0', 'prefix': 'ruby2.7-doc', 'reference': '2.7.4-1+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_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, 'libruby2.7 / ruby2.7 / ruby2.7-dev / ruby2.7-doc');
}