Vulnerabilities > CVE-2016-4356 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in multiple products

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
gnupg
canonical
CWE-119
nessus

Summary

The append_utf8_value function in the DN decoder (dn.c) in Libksba before 1.3.3 allows remote attackers to cause a denial of service (out-of-bounds read) by clearing the high bit of the byte after invalid utf-8 encoded data.

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Nessus

  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-2982-1.NASL
    descriptionHanno Bock discovered that Libksba incorrectly handled decoding certain BER data. An attacker could use this issue to cause Libksba to crash, resulting in a denial of service. This issue only applied to Ubunt 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-4353) Hanno Bock discovered that Libksba incorrectly handled decoding certain BER data. An attacker could use this issue to cause Libksba to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only applied to Ubunt 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-4354, CVE-2016-4355) Hanno Bock discovered that Libksba incorrectly handled incorrect utf-8 strings when decoding certain DN data. An attacker could use this issue to cause Libksba to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only applied to Ubunt 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-4356) Pascal Cuoq discovered that Libksba incorrectly handled incorrect utf-8 strings when decoding certain DN data. An attacker could use this issue to cause Libksba to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-4574) Pascal Cuoq discovered that Libksba incorrectly handled decoding certain data. An attacker could use this issue to cause Libksba to crash, resulting in a denial of service. (CVE-2016-4579). 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 id91220
    published2016-05-18
    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/91220
    titleUbuntu 12.04 LTS / 14.04 LTS / 15.10 / 16.04 LTS : libksba vulnerabilities (USN-2982-1)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Ubuntu Security Notice USN-2982-1. 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(91220);
      script_version("2.11");
      script_cvs_date("Date: 2019/09/18 12:31:45");
    
      script_cve_id("CVE-2016-4353", "CVE-2016-4354", "CVE-2016-4355", "CVE-2016-4356", "CVE-2016-4574", "CVE-2016-4579");
      script_xref(name:"USN", value:"2982-1");
    
      script_name(english:"Ubuntu 12.04 LTS / 14.04 LTS / 15.10 / 16.04 LTS : libksba vulnerabilities (USN-2982-1)");
      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:
    "Hanno Bock discovered that Libksba incorrectly handled decoding
    certain BER data. An attacker could use this issue to cause Libksba to
    crash, resulting in a denial of service. This issue only applied to
    Ubunt 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-4353)
    
    Hanno Bock discovered that Libksba incorrectly handled decoding
    certain BER data. An attacker could use this issue to cause Libksba to
    crash, resulting in a denial of service, or possibly execute arbitrary
    code. This issue only applied to Ubunt 12.04 LTS and Ubuntu 14.04 LTS.
    (CVE-2016-4354, CVE-2016-4355)
    
    Hanno Bock discovered that Libksba incorrectly handled incorrect
    utf-8 strings when decoding certain DN data. An attacker could use
    this issue to cause Libksba to crash, resulting in a denial of
    service, or possibly execute arbitrary code. This issue only applied
    to Ubunt 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2016-4356)
    
    Pascal Cuoq discovered that Libksba incorrectly handled incorrect
    utf-8 strings when decoding certain DN data. An attacker could use
    this issue to cause Libksba to crash, resulting in a denial of
    service, or possibly execute arbitrary code. (CVE-2016-4574)
    
    Pascal Cuoq discovered that Libksba incorrectly handled decoding
    certain data. An attacker could use this issue to cause Libksba to
    crash, resulting in a denial of service. (CVE-2016-4579).
    
    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/2982-1/"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected libksba8 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:"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:canonical:ubuntu_linux:libksba8");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:12.04:-:lts");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:15.10");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2016/06/13");
      script_set_attribute(attribute:"patch_publication_date", value:"2016/05/17");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/05/18");
      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:"^(12\.04|14\.04|15\.10|16\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 12.04 / 14.04 / 15.10 / 16.04", "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:"12.04", pkgname:"libksba8", pkgver:"1.2.0-2ubuntu0.2")) flag++;
    if (ubuntu_check(osver:"14.04", pkgname:"libksba8", pkgver:"1.3.0-3ubuntu0.14.04.2")) flag++;
    if (ubuntu_check(osver:"15.10", pkgname:"libksba8", pkgver:"1.3.3-1ubuntu0.15.10.1")) flag++;
    if (ubuntu_check(osver:"16.04", pkgname:"libksba8", pkgver:"1.3.3-1ubuntu0.16.04.1")) 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, "libksba8");
    }
    
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2016-624.NASL
    descriptionThis update for libksba fixes the following issues : Security issue fixed : - boo#979261: OOB read access bugs remote DoS - CVE-2016-4574: off-by-one OOB read access (incomplete fix for CVE-2016-4356)
    last seen2020-06-05
    modified2016-05-23
    plugin id91289
    published2016-05-23
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/91289
    titleopenSUSE Security Update : libksba (openSUSE-2016-624)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from openSUSE Security Update openSUSE-2016-624.
    #
    # The text description of this plugin is (C) SUSE LLC.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(91289);
      script_version("2.4");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");
    
      script_cve_id("CVE-2016-4356", "CVE-2016-4574");
    
      script_name(english:"openSUSE Security Update : libksba (openSUSE-2016-624)");
      script_summary(english:"Check for the openSUSE-2016-624 patch");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote openSUSE host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "This update for libksba fixes the following issues :
    
    Security issue fixed :
    
      - boo#979261: OOB read access bugs remote DoS
    
      - CVE-2016-4574: off-by-one OOB read access (incomplete
        fix for CVE-2016-4356)"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.opensuse.org/show_bug.cgi?id=979261"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected libksba packages."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
      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_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:libksba-debugsource");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:libksba-devel");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:libksba8");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:libksba8-debuginfo");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:13.2");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2016/05/20");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/05/23");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2016-2020 Tenable Network Security, Inc.");
      script_family(english:"SuSE Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/SuSE/release", "Host/SuSE/rpm-list", "Host/cpu");
    
      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/SuSE/release");
    if (isnull(release) || release =~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "openSUSE");
    if (release !~ "^(SUSE13\.2)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "13.2", release);
    if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    ourarch = get_kb_item("Host/cpu");
    if (!ourarch) audit(AUDIT_UNKNOWN_ARCH);
    if (ourarch !~ "^(i586|i686|x86_64)$") audit(AUDIT_ARCH_NOT, "i586 / i686 / x86_64", ourarch);
    
    flag = 0;
    
    if ( rpm_check(release:"SUSE13.2", reference:"libksba-debugsource-1.3.1-12.1") ) flag++;
    if ( rpm_check(release:"SUSE13.2", reference:"libksba-devel-1.3.1-12.1") ) flag++;
    if ( rpm_check(release:"SUSE13.2", reference:"libksba8-1.3.1-12.1") ) flag++;
    if ( rpm_check(release:"SUSE13.2", reference:"libksba8-debuginfo-1.3.1-12.1") ) 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, "libksba-debugsource / libksba-devel / libksba8 / libksba8-debuginfo");
    }
    
  • NASL familyAmazon Linux Local Security Checks
    NASL idALA_ALAS-2016-712.NASL
    descriptionThe following security-related issues were resolved : Incomplete fix for CVE-2016-4356 (CVE-2016-4574) Out-of-bounds read in _ksba_ber_parse_tl (CVE-2016-4579)
    last seen2020-06-01
    modified2020-06-02
    plugin id91471
    published2016-06-06
    reporterThis script is Copyright (C) 2016-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/91471
    titleAmazon Linux AMI : libksba (ALAS-2016-712)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_A113404810C611E694FA002590263BF5.NASL
    descriptionMartin Prpic, Red Hat Product Security Team, reports : Denial of Service due to stack overflow in src/ber-decoder.c. Integer overflow in the BER decoder src/ber-decoder.c. Integer overflow in the DN decoder src/dn.c.
    last seen2020-06-01
    modified2020-06-02
    plugin id90848
    published2016-05-03
    reporterThis script is Copyright (C) 2016-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/90848
    titleFreeBSD : libksba -- local denial of service vulnerabilities (a1134048-10c6-11e6-94fa-002590263bf5)