Amazon Linux AMI : python26 (ALAS-2012-98)

2013-09-04T00:00:00
ID ALA_ALAS-2012-98.NASL
Type nessus
Reporter Tenable
Modified 2018-04-18T00:00:00

Description

A denial of service flaw was found in the implementation of associative arrays (dictionaries) in Python. An attacker able to supply a large number of inputs to a Python application (such as HTTP POST request parameters sent to a web application) that are used as keys when inserting data into an array could trigger multiple hash function collisions, making array operations take an excessive amount of CPU time. To mitigate this issue, randomization has been added to the hash function to reduce the chance of an attacker successfully causing intentional collisions. (CVE-2012-1150)

Note: The hash randomization is not enabled by default as it may break applications that incorrectly depend on dictionary ordering. To enable the protection, the new 'PYTHONHASHSEED' environment variable or the Python interpreter's '-R' command line option can be used. Refer to the python(1) manual page for details.

A flaw was found in the way the Python SimpleXMLRPCServer module handled clients disconnecting prematurely. A remote attacker could use this flaw to cause excessive CPU consumption on a server using SimpleXMLRPCServer. (CVE-2012-0845)

A flaw was found in the way the Python SimpleHTTPServer module generated directory listings. An attacker able to upload a file with a specially crafted name to a server could possibly perform a cross-site scripting (XSS) attack against victims visiting a listing page generated by SimpleHTTPServer, for a directory containing the crafted file (if the victims were using certain web browsers). (CVE-2011-4940)

A race condition was found in the way the Python distutils module set file permissions during the creation of the .pypirc file. If a local user had access to the home directory of another user who is running distutils, they could use this flaw to gain access to that user's .pypirc file, which can contain usernames and passwords for code repositories. (CVE-2011-4944)

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2012-98.
#

include("compat.inc");

if (description)
{
  script_id(69705);
  script_version("1.6");
  script_cvs_date("Date: 2018/04/18 15:09:34");

  script_cve_id("CVE-2011-4940", "CVE-2011-4944", "CVE-2012-0845", "CVE-2012-1150");
  script_xref(name:"ALAS", value:"2012-98");
  script_xref(name:"RHSA", value:"2012:0744");

  script_name(english:"Amazon Linux AMI : python26 (ALAS-2012-98)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Amazon Linux AMI host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"A denial of service flaw was found in the implementation of
associative arrays (dictionaries) in Python. An attacker able to
supply a large number of inputs to a Python application (such as HTTP
POST request parameters sent to a web application) that are used as
keys when inserting data into an array could trigger multiple hash
function collisions, making array operations take an excessive amount
of CPU time. To mitigate this issue, randomization has been added to
the hash function to reduce the chance of an attacker successfully
causing intentional collisions. (CVE-2012-1150)

Note: The hash randomization is not enabled by default as it may break
applications that incorrectly depend on dictionary ordering. To enable
the protection, the new 'PYTHONHASHSEED' environment variable or the
Python interpreter's '-R' command line option can be used. Refer to
the python(1) manual page for details.

A flaw was found in the way the Python SimpleXMLRPCServer module
handled clients disconnecting prematurely. A remote attacker could use
this flaw to cause excessive CPU consumption on a server using
SimpleXMLRPCServer. (CVE-2012-0845)

A flaw was found in the way the Python SimpleHTTPServer module
generated directory listings. An attacker able to upload a file with a
specially crafted name to a server could possibly perform a cross-site
scripting (XSS) attack against victims visiting a listing page
generated by SimpleHTTPServer, for a directory containing the crafted
file (if the victims were using certain web browsers). (CVE-2011-4940)

A race condition was found in the way the Python distutils module set
file permissions during the creation of the .pypirc file. If a local
user had access to the home directory of another user who is running
distutils, they could use this flaw to gain access to that user's
.pypirc file, which can contain usernames and passwords for code
repositories. (CVE-2011-4944)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/ALAS-2012-98.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update python26' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26-test");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python26-tools");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");

  script_set_attribute(attribute:"patch_publication_date", value:"2012/07/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2013/09/04");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2013-2018 Tenable Network Security, Inc.");
  script_family(english:"Amazon Linux Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  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/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

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


flag = 0;
if (rpm_check(release:"ALA", reference:"python26-2.6.8-2.28.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"python26-debuginfo-2.6.8-2.28.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"python26-devel-2.6.8-2.28.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"python26-libs-2.6.8-2.28.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"python26-test-2.6.8-2.28.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"python26-tools-2.6.8-2.28.amzn1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "python26 / python26-debuginfo / python26-devel / python26-libs / etc");
}