Debian DSA-2417-1 : libxml2 - computational denial of service

2012-02-23T00:00:00
ID DEBIAN_DSA-2417.NASL
Type nessus
Reporter Tenable
Modified 2018-07-09T00:00:00

Description

It was discovered that the internal hashing routine of libxml2, a library providing an extensive API to handle XML data, is vulnerable to predictable hash collisions. Given an attacker with knowledge of the hashing algorithm, it is possible to craft input that creates a large amount of collisions. As a result it is possible to perform denial of service attacks against applications using libxml2 functionality because of the computational overhead.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-2417. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(58097);
  script_version("1.15");
  script_cvs_date("Date: 2018/07/09 14:30:25");

  script_cve_id("CVE-2012-0841");
  script_bugtraq_id(52107);
  script_xref(name:"DSA", value:"2417");

  script_name(english:"Debian DSA-2417-1 : libxml2 - computational denial of service");
  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:
"It was discovered that the internal hashing routine of libxml2, a
library providing an extensive API to handle XML data, is vulnerable
to predictable hash collisions. Given an attacker with knowledge of
the hashing algorithm, it is possible to craft input that creates a
large amount of collisions. As a result it is possible to perform
denial of service attacks against applications using libxml2
functionality because of the computational overhead."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/squeeze/libxml2"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.debian.org/security/2012/dsa-2417"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the libxml2 packages.

For the stable distribution (squeeze), this problem has been fixed in
version 2.7.8.dfsg-2+squeeze3."
  );
  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_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:libxml2");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:6.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2012/02/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2012/02/23");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2012-2018 Tenable Network Security, Inc.");
  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:"6.0", prefix:"libxml2", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"libxml2-dbg", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"libxml2-dev", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"libxml2-doc", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"libxml2-utils", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"python-libxml2", reference:"2.7.8.dfsg-2+squeeze3")) flag++;
if (deb_check(release:"6.0", prefix:"python-libxml2-dbg", reference:"2.7.8.dfsg-2+squeeze3")) 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");