EulerOS 2.0 SP1 : libxml2 (EulerOS-SA-2017-1237)

2017-10-10T00:00:00
ID EULEROS_SA-2017-1237.NASL
Type nessus
Reporter Tenable
Modified 2018-11-14T00:00:00

Description

According to the version of the libxml2 packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  • A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer 'buf' of size 'size'. The variable len is assigned strlen(buf). If the content->type is XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits) whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name actually fits also uses 'len' rather than the updated buffer length strlen(buf). This allows us to write about 'size' many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2, such as PHP, to crash.(CVE-2017-9047)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(103739);
  script_version("3.8");
  script_cvs_date("Date: 2018/11/14 14:36:23");

  script_cve_id(
    "CVE-2017-9047"
  );

  script_name(english:"EulerOS 2.0 SP1 : libxml2 (EulerOS-SA-2017-1237)");
  script_summary(english:"Checks the rpm output for the updated package.");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"According to the version of the libxml2 packages installed, the
EulerOS installation on the remote host is affected by the following
vulnerability :

  - A buffer overflow was discovered in libxml2
    20904-GITv2.9.4-16-g0741801. The function
    xmlSnprintfElementContent in valid.c is supposed to
    recursively dump the element content definition into a
    char buffer 'buf' of size 'size'. The variable len is
    assigned strlen(buf). If the content->type is
    XML_ELEMENT_CONTENT_ELEMENT, then (i) the
    content->prefix is appended to buf (if it actually
    fits) whereupon (ii) content->name is written to the
    buffer. However, the check for whether the
    content->name actually fits also uses 'len' rather than
    the updated buffer length strlen(buf). This allows us
    to write about 'size' many bytes beyond the allocated
    memory. This vulnerability causes programs that use
    libxml2, such as PHP, to crash.(CVE-2017-9047)

Note that Tenable Network Security has extracted the preceding
description block directly from the EulerOS security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  # https://developer.huawei.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2017-1237
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1e9ed817");
  script_set_attribute(attribute:"solution", value:
"Update the affected libxml2 package.");
  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:U/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:U/RL:O/RC:C");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/09/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libxml2-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libxml2-python");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/10/10");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

release = get_kb_item("Host/EulerOS/release");
if (isnull(release) || release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
if (release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0");

sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(1)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP1");

uvp = get_kb_item("Host/EulerOS/uvp_version");
if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP1", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);

flag = 0;

pkgs = ["libxml2-2.9.1-6.3.h3",
        "libxml2-devel-2.9.1-6.3.h3",
        "libxml2-python-2.9.1-6.3.h3"];

foreach (pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"1", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "libxml2");
}