Debian DSA-3729-1 : xen - security update

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-3729. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(95610);
  script_version("3.15");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/11");

  script_cve_id("CVE-2016-7777", "CVE-2016-9379", "CVE-2016-9380", "CVE-2016-9382", "CVE-2016-9383", "CVE-2016-9385", "CVE-2016-9386");
  script_xref(name:"DSA", value:"3729");
  script_xref(name:"IAVB", value:"2016-B-0149-S");

  script_name(english:"Debian DSA-3729-1 : xen - security update");
  script_summary(english:"Checks dpkg output for the updated package");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Multiple vulnerabilities have been discovered in the Xen hypervisor.
The Common Vulnerabilities and Exposures project identifies the
following problems :

  - CVE-2016-7777 (XSA-190)
    Jan Beulich from SUSE discovered that Xen does not
    properly honor CR0.TS and CR0.EM for x86 HVM guests,
    potentially allowing guest users to read or modify FPU,
    MMX, or XMM register state information belonging to
    arbitrary tasks on the guest by modifying an instruction
    while the hypervisor is preparing to emulate it.

  - CVE-2016-9379, CVE-2016-9380 (XSA-198)
    Daniel Richman and Gabor Szarka of the Cambridge
    University Student-Run Computing Facility discovered
    that pygrub, the boot loader emulator, fails to quote
    (or sanity check) its results when reporting them to its
    caller. A malicious guest administrator can take
    advantage of this flaw to cause an information leak or
    denial of service.

  - CVE-2016-9382 (XSA-192)
    Jan Beulich of SUSE discovered that Xen does not
    properly handle x86 task switches to VM86 mode. A
    unprivileged guest process can take advantage of this
    flaw to crash the guest or, escalate its privileges to
    that of the guest operating system.

  - CVE-2016-9383 (XSA-195)
    George Dunlap of Citrix discovered that the Xen x86
    64-bit bit test instruction emulation is broken. A
    malicious guest can take advantage of this flaw to
    modify arbitrary memory, allowing for arbitrary code
    execution, denial of service (host crash), or
    information leaks.

  - CVE-2016-9385 (XSA-193)
    Andrew Cooper of Citrix discovered that Xen's x86
    segment base write emulation lacks canonical address
    checks. A malicious guest administrator can take
    advantage of this flaw to crash the host, leading to a
    denial of service.

  - CVE-2016-9386 (XSA-191)
    Andrew Cooper of Citrix discovered that x86 null
    segments are not always treated as unusable. An
    unprivileged guest user program may be able to elevate
    its privilege to that of the guest operating system."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=845663"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=845664"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=845665"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=845668"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=845670"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-7777"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9379"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9380"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9382"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9383"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9385"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-9386"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/xen"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2016/dsa-3729"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the xen packages.

For the stable distribution (jessie), these problems have been fixed
in version 4.4.1-9+deb8u8."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/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:L/AC:L/PR:L/UI:N/S:C/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:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:xen");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2016/12/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/08");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2021 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:"8.0", prefix:"libxen-4.4", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libxen-dev", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libxenstore3.0", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-hypervisor-4.4-amd64", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-hypervisor-4.4-arm64", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-hypervisor-4.4-armhf", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-system-amd64", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-system-arm64", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-system-armhf", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-utils-4.4", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xen-utils-common", reference:"4.4.1-9+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"xenstore-utils", reference:"4.4.1-9+deb8u8")) flag++;

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