Debian DLA-2490-1 : x11vnc security update

2020-12-11T00:00:00
ID DEBIAN_DLA-2490.NASL
Type nessus
Reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-12-15T00:00:00

Description

Guenal Davalan reported a flaw in x11vnc, a VNC server to allow remote access to an existing X session. x11vnc creates shared memory segments with 0777 mode. A local attacker can take advantage of this flaw for information disclosure, denial of service or interfering with the VNC session of another user on the host.

For Debian 9 stretch, this problem has been fixed in version 0.9.13-2+deb9u2.

We recommend that you upgrade your x11vnc packages.

For the detailed security status of x11vnc please refer to its security tracker page at: https://security-tracker.debian.org/tracker/x11vnc

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.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-2490-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(144099);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/12/15");

  script_cve_id("CVE-2020-29074");

  script_name(english:"Debian DLA-2490-1 : x11vnc security update");
  script_summary(english:"Checks dpkg output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis",
    value:"The remote Debian host is missing a security update."
  );
  script_set_attribute(
    attribute:"description",
    value:
"Guenal Davalan reported a flaw in x11vnc, a VNC server to allow remote
access to an existing X session. x11vnc creates shared memory segments
with 0777 mode. A local attacker can take advantage of this flaw for
information disclosure, denial of service or interfering with the VNC
session of another user on the host.

For Debian 9 stretch, this problem has been fixed in version
0.9.13-2+deb9u2.

We recommend that you upgrade your x11vnc packages.

For the detailed security status of x11vnc please refer to its
security tracker page at:
https://security-tracker.debian.org/tracker/x11vnc

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/2020/12/msg00018.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/stretch/x11vnc"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/x11vnc"
  );
  script_set_attribute(
    attribute:"solution",
    value:"Upgrade the affected x11vnc, and x11vnc-data packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  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:L/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:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:x11vnc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:x11vnc-data");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/11/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/12/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/12/11");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Debian Local Security Checks");

  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:"x11vnc", reference:"0.9.13-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"x11vnc-data", reference:"0.9.13-2+deb9u2")) 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");