Vulnerabilities > CVE-2020-11501 - Use of Insufficiently Random Values vulnerability in multiple products
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
NONE Summary
GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS. The earliest affected version is 3.6.3 (2018-07-16) because of an error in a 2017-10-06 commit. The DTLS client always uses 32 '\0' bytes instead of a random value, and thus contributes no randomness to a DTLS negotiation. This breaks the security guarantees of the DTLS protocol.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 10 | |
| OS | 1 | |
| OS | 1 | |
| OS | 1 | |
| OS | 2 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Brute Force In this attack, some asset (information, functionality, identity, etc.) is protected by a finite secret value. The attacker attempts to gain access to this asset by using trial-and-error to exhaustively explore all the possible secret values in the hope of finding the secret (or a value that is functionally equivalent) that will unlock the asset. Examples of secrets can include, but are not limited to, passwords, encryption keys, database lookup keys, and initial values to one-way functions. The key factor in this attack is the attackers' ability to explore the possible secret space rapidly. This, in turn, is a function of the size of the secret space and the computational power the attacker is able to bring to bear on the problem. If the attacker has modest resources and the secret space is large, the challenge facing the attacker is intractable. While the defender cannot control the resources available to an attacker, they can control the size of the secret space. Creating a large secret space involves selecting one's secret from as large a field of equally likely alternative secrets as possible and ensuring that an attacker is unable to reduce the size of this field using available clues or cryptanalysis. Doing this is more difficult than it sounds since elimination of patterns (which, in turn, would provide an attacker clues that would help them reduce the space of potential secrets) is difficult to do using deterministic machines, such as computers. Assuming a finite secret space, a brute force attack will eventually succeed. The defender must rely on making sure that the time and resources necessary to do so will exceed the value of the information. For example, a secret space that will likely take hundreds of years to explore is likely safe from raw-brute force attacks.
- Signature Spoofing by Key Recreation An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.
- Session Credential Falsification through Prediction This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.
Nessus
NASL family Red Hat Local Security Checks NASL id REDHAT-RHSA-2020-1998.NASL description The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2020:1998 advisory. - gnutls: DTLS client hello contains a random value of all zeroes (CVE-2020-11501) Note that Nessus has not tested for this issue but has instead relied only on the application last seen 2020-05-03 modified 2020-04-30 plugin id 136187 published 2020-04-30 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/136187 title RHEL 8 : gnutls (RHSA-2020:1998) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Red Hat Security Advisory RHSA-2020:1998. The text # itself is copyright (C) Red Hat, Inc. # include('compat.inc'); if (description) { script_id(136187); script_version("1.2"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/01"); script_cve_id("CVE-2020-11501"); script_xref(name:"RHSA", value:"2020:1998"); script_name(english:"RHEL 8 : gnutls (RHSA-2020:1998)"); script_summary(english:"Checks the rpm output for the updated packages"); script_set_attribute(attribute:"synopsis", value: "The remote Red Hat host is missing a security update."); script_set_attribute(attribute:"description", value: "The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2020:1998 advisory. - gnutls: DTLS client hello contains a random value of all zeroes (CVE-2020-11501) Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number."); script_set_attribute(attribute:"see_also", value:"https://cwe.mitre.org/data/definitions/327.html"); script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2020:1998"); script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2020-11501"); script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/1821896"); script_set_attribute(attribute:"solution", value: "Update the affected packages."); script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N"); script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C"); script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"); script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C"); script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-11501"); script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available"); script_cwe_id(327); script_set_attribute(attribute:"vuln_publication_date", value:"2020/04/03"); script_set_attribute(attribute:"patch_publication_date", value:"2020/04/30"); script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/30"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"cpe:/a:redhat:enterprise_linux:8"); script_set_attribute(attribute:"cpe", value:"cpe:/a:redhat:enterprise_linux:8::appstream"); script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8"); script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8::baseos"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls-c++"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls-dane"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls-debugsource"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls-devel"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnutls-utils"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_family(english:"Red Hat Local Security Checks"); script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof."); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu"); exit(0); } include('audit.inc'); include('global_settings.inc'); include('misc_func.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) || 'Red Hat' >!< release) audit(AUDIT_OS_NOT, 'Red Hat'); os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:release); if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat'); os_ver = os_ver[1]; if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Red Hat 8.x', 'Red Hat ' + os_ver); if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item('Host/cpu'); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu); pkgs = [ {'reference':'gnutls-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-3.6.8-10.el8_2', 'cpu':'i686', 'release':'8'}, {'reference':'gnutls-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'}, {'reference':'gnutls-c++-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-c++-3.6.8-10.el8_2', 'cpu':'i686', 'release':'8'}, {'reference':'gnutls-c++-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-c++-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'}, {'reference':'gnutls-dane-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-dane-3.6.8-10.el8_2', 'cpu':'i686', 'release':'8'}, {'reference':'gnutls-dane-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-dane-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'}, {'reference':'gnutls-debugsource-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-debugsource-3.6.8-10.el8_2', 'cpu':'i686', 'release':'8'}, {'reference':'gnutls-debugsource-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-debugsource-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'}, {'reference':'gnutls-devel-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-devel-3.6.8-10.el8_2', 'cpu':'i686', 'release':'8'}, {'reference':'gnutls-devel-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-devel-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'}, {'reference':'gnutls-utils-3.6.8-10.el8_2', 'cpu':'aarch64', 'release':'8'}, {'reference':'gnutls-utils-3.6.8-10.el8_2', 'cpu':'s390x', 'release':'8'}, {'reference':'gnutls-utils-3.6.8-10.el8_2', 'cpu':'x86_64', 'release':'8'} ]; flag = 0; foreach package_array ( pkgs ) { reference = NULL; release = NULL; sp = NULL; cpu = NULL; el_string = NULL; rpm_spec_vers_cmp = NULL; epoch = NULL; if (!empty_or_null(package_array['reference'])) reference = package_array['reference']; if (!empty_or_null(package_array['release'])) release = 'RHEL' + package_array['release']; if (!empty_or_null(package_array['sp'])) sp = package_array['sp']; if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu']; if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string']; if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp']; if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch']; if (reference && release) { if (rpm_spec_vers_cmp) { if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:TRUE)) flag++; } else { if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch)) flag++; } } } if (flag) { security_report_v4( port : 0, severity : SECURITY_WARNING, extra : rpm_report_get() + redhat_report_package_caveat() ); exit(0); } else { tested = pkg_tests_get(); if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested); else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'gnutls / gnutls-c++ / gnutls-dane / etc'); }NASL family Ubuntu Local Security Checks NASL id UBUNTU_USN-4322-1.NASL description It was discovered that GnuTLS incorrectly handled randomness when performing DTLS negotiation. A remote attacker could possibly use this issue to obtain sensitive information, contrary to expectations. 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 seen 2020-04-16 modified 2020-04-08 plugin id 135283 published 2020-04-08 reporter Ubuntu Security Notice (C) 2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135283 title Ubuntu 19.10 : gnutls28 vulnerability (USN-4322-1) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Ubuntu Security Notice USN-4322-1. 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(135283); script_version("1.2"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/14"); script_cve_id("CVE-2020-11501"); script_xref(name:"USN", value:"4322-1"); script_name(english:"Ubuntu 19.10 : gnutls28 vulnerability (USN-4322-1)"); 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: "It was discovered that GnuTLS incorrectly handled randomness when performing DTLS negotiation. A remote attacker could possibly use this issue to obtain sensitive information, contrary to expectations. 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/4322-1/" ); script_set_attribute( attribute:"solution", value:"Update the affected libgnutls30 package." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N"); 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:N"); 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:canonical:ubuntu_linux:libgnutls30"); script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.10"); script_set_attribute(attribute:"vuln_publication_date", value:"2020/04/03"); script_set_attribute(attribute:"patch_publication_date", value:"2020/04/07"); script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/08"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"Ubuntu Security Notice (C) 2020 Canonical, Inc. / NASL script (C) 2020 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:"^(19\.10)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 19.10", "Ubuntu " + release); if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu); flag = 0; if (ubuntu_check(osver:"19.10", pkgname:"libgnutls30", pkgver:"3.6.9-5ubuntu1.1")) 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, "libgnutls30"); }NASL family Debian Local Security Checks NASL id DEBIAN_DSA-4652.NASL description A flaw was reported in the DTLS protocol implementation in GnuTLS, a library implementing the TLS and SSL protocols. The DTLS client would not contribute any randomness to the DTLS negotiation, breaking the security guarantees of the DTLS protocol. last seen 2020-04-12 modified 2020-04-06 plugin id 135207 published 2020-04-06 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135207 title Debian DSA-4652-1 : gnutls28 - security update NASL family Oracle Linux Local Security Checks NASL id ORACLELINUX_ELSA-2020-1998.NASL description From Red Hat Security Advisory 2020:1998 : The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2020:1998 advisory. - gnutls: DTLS client hello contains a random value of all zeroes (CVE-2020-11501) Note that Nessus has not tested for this issue but has instead relied only on the application last seen 2020-06-06 modified 2020-05-11 plugin id 136447 published 2020-05-11 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/136447 title Oracle Linux 8 : gnutls (ELSA-2020-1998) NASL family PhotonOS Local Security Checks NASL id PHOTONOS_PHSA-2020-3_0-0080_GNUTLS.NASL description An update of the gnutls package has been released. last seen 2020-04-30 modified 2020-04-21 plugin id 135792 published 2020-04-21 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135792 title Photon OS 3.0: Gnutls PHSA-2020-3.0-0080 NASL family SuSE Local Security Checks NASL id OPENSUSE-2020-501.NASL description This update for gmp, gnutls, libnettle fixes the following issues : Security issue fixed : - CVE-2020-11501: Fixed zero random value in DTLS client hello (bsc#1168345) FIPS related bugfixes : - FIPS: Install checksums for binary integrity verification which are required when running in FIPS mode (bsc#1152692, jsc#SLE-9518) - FIPS: Fixed a cfb8 decryption issue, no longer truncate output IV if input is shorter than block size. (bsc#1166881) - FIPS: Added Diffie Hellman public key verification test. (bsc#1155327) This update was imported from the SUSE:SLE-15:Update update project. last seen 2020-04-17 modified 2020-04-14 plugin id 135449 published 2020-04-14 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135449 title openSUSE Security Update : gmp / gnutls / libnettle (openSUSE-2020-501) NASL family Fedora Local Security Checks NASL id FEDORA_2020-D14280A6E8.NASL description https://lists.gnupg.org/pipermail/gnutls-help/2020-March/004642.html 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 seen 2020-05-15 modified 2020-05-08 plugin id 136416 published 2020-05-08 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/136416 title Fedora 31 : mingw-gnutls (2020-d14280a6e8) NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_D887B3D9736611EAB81A001CC0382B2F.NASL description The GnuTLS project reports : It was found that GnuTLS 3.6.3 introduced a regression in the DTLS protocol implementation. This caused the DTLS client to not contribute any randomness to the DTLS negotiation breaking the security guarantees of the DTLS protocol. last seen 2020-06-10 modified 2020-04-02 plugin id 135110 published 2020-04-02 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135110 title FreeBSD : GnuTLS -- flaw in DTLS protocol implementation (d887b3d9-7366-11ea-b81a-001cc0382b2f) NASL family SuSE Local Security Checks NASL id SUSE_SU-2020-0948-1.NASL description This update for gmp, gnutls, libnettle fixes the following issues : Security issue fixed : CVE-2020-11501: Fixed zero random value in DTLS client hello (bsc#1168345) FIPS related bugfixes: FIPS: Install checksums for binary integrity verification which are required when running in FIPS mode (bsc#1152692, jsc#SLE-9518) FIPS: Fixed a cfb8 decryption issue, no longer truncate output IV if input is shorter than block size. (bsc#1166881) FIPS: Added Diffie Hellman public key verification test. (bsc#1155327) 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 seen 2020-04-16 modified 2020-04-10 plugin id 135387 published 2020-04-10 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135387 title SUSE SLED15 / SLES15 Security Update : gmp, gnutls, libnettle (SUSE-SU-2020:0948-1)
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References
- https://gitlab.com/gnutls/gnutls/-/commit/5b595e8e52653f6c5726a4cdd8fddeb6e83804d2
- https://gitlab.com/gnutls/gnutls/-/issues/960
- https://www.gnutls.org/security-new.html#GNUTLS-SA-2020-03-31
- https://www.debian.org/security/2020/dsa-4652
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00015.html
- https://security.netapp.com/advisory/ntap-20200416-0002/
- https://usn.ubuntu.com/4322-1/
- https://security.gentoo.org/glsa/202004-06
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WDYY3R4F5CUTFAMXH2C5NKYFVDEJLTT7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ILMOWPKMTZAIMK5F32TUMO34XCABUCFJ/