Vulnerabilities > CVE-2020-1747

047910
CVSS 9.8 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
pyyaml
fedoraproject
opensuse
oracle
critical
nessus

Summary

A vulnerability was discovered in the PyYAML library in versions before 5.3.1, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the full_load method or with the FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this flaw. An attacker could use this flaw to execute arbitrary code on the system by abusing the python/object/new constructor.

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2020-BDB0BFA928.NASL
    description - New upstream release 5.3.1 (rhbz#1814882) - Fixes CVE-2020-1747 (rhbz#1807367,1809011) Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-04-03
    modified2020-03-30
    plugin id134996
    published2020-03-30
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134996
    titleFedora 31 : PyYAML (2020-bdb0bfa928)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Fedora Security Advisory FEDORA-2020-bdb0bfa928.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(134996);
      script_version("1.3");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/02");
    
      script_cve_id("CVE-2020-1747");
      script_xref(name:"FEDORA", value:"2020-bdb0bfa928");
    
      script_name(english:"Fedora 31 : PyYAML (2020-bdb0bfa928)");
      script_summary(english:"Checks rpm output for the updated package.");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Fedora host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "  - New upstream release 5.3.1 (rhbz#1814882)
    
      - Fixes CVE-2020-1747 (rhbz#1807367,1809011)
    
    Note that Tenable Network Security has extracted the preceding
    description block directly from the Fedora update system website.
    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://bodhi.fedoraproject.org/updates/FEDORA-2020-bdb0bfa928"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected PyYAML package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
      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:H/I:H/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:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:PyYAML");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:31");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2020/03/24");
      script_set_attribute(attribute:"patch_publication_date", value:"2020/03/27");
      script_set_attribute(attribute:"plugin_publication_date", value:"2020/03/30");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Fedora Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/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/RedHat/release");
    if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
    os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
    if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
    os_ver = os_ver[1];
    if (! preg(pattern:"^31([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 31", "Fedora " + os_ver);
    
    if (!get_kb_item("Host/RedHat/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, "Fedora", cpu);
    
    
    flag = 0;
    if (rpm_check(release:"FC31", reference:"PyYAML-5.3.1-1.fc31")) flag++;
    
    
    if (flag)
    {
      security_report_v4(
        port       : 0,
        severity   : SECURITY_HOLE,
        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, "PyYAML");
    }
    
  • NASL familyPhotonOS Local Security Checks
    NASL idPHOTONOS_PHSA-2020-1_0-0290_PYYAML.NASL
    descriptionAn update of the PyYAML package has been released.
    last seen2020-05-03
    modified2020-04-29
    plugin id136104
    published2020-04-29
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136104
    titlePhoton OS 1.0: Pyyaml PHSA-2020-1.0-0290
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2020-0959-1.NASL
    descriptionThis update for python-PyYAML fixes the following issues : CVE-2020-1747: Fixed an arbitrary code execution when YAML files are parsed by FullLoader (bsc#1165439). Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-04-16
    modified2020-04-10
    plugin id135390
    published2020-04-10
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/135390
    titleSUSE SLED15 / SLES15 Security Update : python-PyYAML (SUSE-SU-2020:0959-1)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2020-630.NASL
    descriptionThis update for python-PyYAML fixes the following issues : - CVE-2020-1747: Fixed an arbitrary code execution when YAML files are parsed by FullLoader (bsc#1165439). This update was imported from the SUSE:SLE-15-SP1:Update update project.
    last seen2020-05-15
    modified2020-05-11
    plugin id136456
    published2020-05-11
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136456
    titleopenSUSE Security Update : python-PyYAML (openSUSE-2020-630)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2020-507.NASL
    descriptionThis update for python-PyYAML fixes the following issues : - CVE-2020-1747: Fixed an arbitrary code execution when YAML files are parsed by FullLoader (bsc#1165439). This update was imported from the SUSE:SLE-15-SP1:Update update project.
    last seen2020-04-17
    modified2020-04-14
    plugin id135451
    published2020-04-14
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/135451
    titleopenSUSE Security Update : python-PyYAML (openSUSE-2020-507)
  • NASL familyPhotonOS Local Security Checks
    NASL idPHOTONOS_PHSA-2020-3_0-0080_PYYAML.NASL
    descriptionAn update of the PyYAML package has been released.
    last seen2020-04-30
    modified2020-04-21
    plugin id135789
    published2020-04-21
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/135789
    titlePhoton OS 3.0: Pyyaml PHSA-2020-3.0-0080
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2020-40C35D7B37.NASL
    description - New upstream release 5.3.1 (rhbz#1814882) - Fixes CVE-2020-1747 (rhbz#1807367,1809011) Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-04-03
    modified2020-03-30
    plugin id134991
    published2020-03-30
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134991
    titleFedora 30 : PyYAML (2020-40c35d7b37)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_AAE8FECF888E11EA971408002718DE91.NASL
    descriptionRiccardo Schirone (https://github.com/ret2libc) reports : In FullLoader python/object/new constructor, implemented by construct_python_object_apply, has support for setting the state of a deserialized instance through the set_python_instance_state method. After setting the state, some operations are performed on the instance to complete its initialization, however it is possible for an attacker to set the instance
    last seen2020-05-03
    modified2020-04-28
    plugin id136021
    published2020-04-28
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136021
    titleFreeBSD : py-yaml -- FullLoader (still) exploitable for arbitrary command execution (aae8fecf-888e-11ea-9714-08002718de91)
  • NASL familyPhotonOS Local Security Checks
    NASL idPHOTONOS_PHSA-2020-2_0-0229_PYYAML.NASL
    descriptionAn update of the PyYAML package has been released.
    last seen2020-04-30
    modified2020-04-22
    plugin id135866
    published2020-04-22
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/135866
    titlePhoton OS 2.0: Pyyaml PHSA-2020-2.0-0229
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2020-1285-1.NASL
    descriptionThis update for python-PyYAML fixes the following issues : CVE-2020-1747: Fixed an arbitrary code execution when YAML files are parsed by FullLoader (bsc#1165439). Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-05-31
    modified2020-05-22
    plugin id136784
    published2020-05-22
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136784
    titleSUSE SLES12 Security Update : python-PyYAML (SUSE-SU-2020:1285-1)

References