Vulnerabilities > CVE-2016-1252 - Improper Certificate Validation vulnerability in multiple products

047910
CVSS 5.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
NONE
network
high complexity
debian
canonical
CWE-295
nessus
exploit available
NVD
Published: 2017-12-05
Updated: 2020-08-14

Summary

The apt package in Debian jessie before 1.0.9.8.4, in Debian unstable before 1.4~beta2, in Ubuntu 14.04 LTS before 1.0.1ubuntu2.17, in Ubuntu 16.04 LTS before 1.2.15ubuntu0.2, and in Ubuntu 16.10 before 1.3.2ubuntu0.1 allows man-in-the-middle attackers to bypass a repository-signing protection mechanism by leveraging improper error handling when validating InRelease file signatures.

Vulnerable Configurations

Part Description Count
Application
Debian
189
OS
Debian
1
OS
Canonical
3

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Creating a Rogue Certificate Authority Certificate
    An attacker exploits a weakness in the MD5 hash algorithm (weak collision resistance) to generate a certificate signing request (CSR) that contains collision blocks in the "to be signed" part. The attacker specially crafts two different, but valid X.509 certificates that when hashed with the MD5 algorithm would yield the same value. The attacker then sends the CSR for one of the certificates to the Certification Authority which uses the MD5 hashing algorithm. That request is completely valid and the Certificate Authority issues an X.509 certificate to the attacker which is signed with its private key. An attacker then takes that signed blob and inserts it into another X.509 certificate that the attacker generated. Due to the MD5 collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the attackers' second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority. To make the attack more interesting, the second certificate could be not just a regular certificate, but rather itself a signing certificate. Thus the attacker is able to start their own Certification Authority that is anchored in its root of trust in the legitimate Certification Authority that has signed the attackers' first X.509 certificate. If the original Certificate Authority was accepted by default by browsers, so will now the Certificate Authority set up by the attacker and of course any certificates that it signs. So the attacker is now able to generate any SSL certificates to impersonate any web server, and the user's browser will not issue any warning to the victim. This can be used to compromise HTTPS communications and other types of systems where PKI and X.509 certificates may be used (e.g., VPN, IPSec) .

Exploit-Db

descriptionAPT - Repository Signing Bypass via Memory Allocation Failure. CVE-2016-1252. Remote exploit for Linux platform
fileexploits/linux/remote/40916.txt
idEDB-ID:40916
last seen2016-12-14
modified2016-12-14
platformlinux
port
published2016-12-14
reporterExploit-DB
sourcehttps://www.exploit-db.com/download/40916/
titleAPT - Repository Signing Bypass via Memory Allocation Failure
typeremote

Nessus

  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-3733.NASL
    descriptionJann Horn of Google Project Zero discovered that APT, the high level package manager, does not properly handle errors when validating signatures on InRelease files. An attacker able to man-in-the-middle HTTP requests to an apt repository that uses InRelease files (clearsigned Release files), can take advantage of this flaw to circumvent the signature of the InRelease file, leading to arbitrary code execution.
    last seen2020-06-01
    modified2020-06-02
    plugin id95777
    published2016-12-14
    reporterThis script is Copyright (C) 2016-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/95777
    titleDebian DSA-3733-1 : apt - security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-3733. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(95777);
  script_version("3.7");
  script_cvs_date("Date: 2018/11/10 11:49:38");

  script_cve_id("CVE-2016-1252");
  script_xref(name:"DSA", value:"3733");

  script_name(english:"Debian DSA-3733-1 : apt - 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:
"Jann Horn of Google Project Zero discovered that APT, the high level
package manager, does not properly handle errors when validating
signatures on InRelease files. An attacker able to man-in-the-middle
HTTP requests to an apt repository that uses InRelease files
(clearsigned Release files), can take advantage of this flaw to
circumvent the signature of the InRelease file, leading to arbitrary
code execution."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/apt"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2016/dsa-3733"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the apt packages.

For the stable distribution (jessie), this problem has been fixed in
version 1.0.9.8.4."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

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

  script_set_attribute(attribute:"patch_publication_date", value:"2016/12/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/14");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2018 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:"apt", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"apt-doc", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"apt-transport-https", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"apt-utils", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"libapt-inst1.5", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"libapt-pkg-dev", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"libapt-pkg-doc", reference:"1.0.9.8.4")) flag++;
if (deb_check(release:"8.0", prefix:"libapt-pkg4.12", reference:"1.0.9.8.4")) 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");
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-3156-1.NASL
    descriptionJann Horn discovered that APT incorrectly handled InRelease files. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could potentially be used to install altered packages. Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id95808
    published2016-12-14
    reporterUbuntu Security Notice (C) 2016-2019 Canonical, Inc. / NASL script (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/95808
    titleUbuntu 14.04 LTS / 16.04 LTS / 16.10 : apt vulnerability (USN-3156-1)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3156-1. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(95808);
  script_version("3.8");
  script_cvs_date("Date: 2019/09/18 12:31:46");

  script_cve_id("CVE-2016-1252");
  script_xref(name:"USN", value:"3156-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 16.10 : apt vulnerability (USN-3156-1)");
  script_summary(english:"Checks dpkg output for updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Ubuntu host is missing a security-related patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Jann Horn discovered that APT incorrectly handled InRelease files. If
a remote attacker were able to perform a man-in-the-middle attack,
this flaw could potentially be used to install altered packages.

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu 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://usn.ubuntu.com/3156-1/"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected apt package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apt");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.10");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/12/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/12/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/14");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2016-2019 Canonical, Inc. / NASL script (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(14\.04|16\.04|16\.10)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 14.04 / 16.04 / 16.10", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) 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, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"14.04", pkgname:"apt", pkgver:"1.0.1ubuntu2.17")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"apt", pkgver:"1.2.15ubuntu0.2")) flag++;
if (ubuntu_check(osver:"16.10", pkgname:"apt", pkgver:"1.3.2ubuntu0.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "apt");
}

References