Debian DLA-2451-1 : libvncserver security update

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-2451-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(142924);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/08");

  script_cve_id("CVE-2020-25708");

  script_name(english:"Debian DLA-2451-1 : libvncserver security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"An issue has been found in libvncserver, an API to write one's own VNC
server. Due to some missing checks, a divide by zero could happen,
which could result in a denial of service.

For Debian 9 stretch, this problem has been fixed in version
0.9.11+dfsg-1.3~deb9u6.

We recommend that you upgrade your libvncserver packages.

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

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues.");
  script_set_attribute(attribute:"see_also", value:"https://lists.debian.org/debian-lts-announce/2020/11/msg00025.html");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/stretch/libvncserver");
  # https://security-tracker.debian.org/tracker/source-package/libvncserver
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b930abb4");
  script_set_attribute(attribute:"solution", value:
"Upgrade the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2020-25708");

  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:"2020/11/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/11/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/11/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncclient1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncclient1-dbg");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncserver-config");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncserver-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncserver1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libvncserver1-dbg");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");
  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) 2020-2024 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("audit.inc");
include("debian_package.inc");


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


flag = 0;
if (deb_check(release:"9.0", prefix:"libvncclient1", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;
if (deb_check(release:"9.0", prefix:"libvncclient1-dbg", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;
if (deb_check(release:"9.0", prefix:"libvncserver-config", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;
if (deb_check(release:"9.0", prefix:"libvncserver-dev", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;
if (deb_check(release:"9.0", prefix:"libvncserver1", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;
if (deb_check(release:"9.0", prefix:"libvncserver1-dbg", reference:"0.9.11+dfsg-1.3~deb9u6")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");