Vulnerabilities > CVE-2019-6690 - Improper Input Validation vulnerability in multiple products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
HIGH Availability impact
NONE Summary
python-gnupg 0.4.3 allows context-dependent attackers to trick gnupg to decrypt other ciphertext than intended. To perform the attack, the passphrase to gnupg must be controlled by the adversary and the ciphertext should be trusted. Related to a "CWE-20: Improper Input Validation" issue affecting the affect functionality component.
Vulnerable Configurations
Part | Description | Count |
---|---|---|
Application | 1 | |
Application | 1 | |
OS | 2 | |
OS | 1 | |
OS | 1 | |
OS | 3 |
Common Weakness Enumeration (CWE)
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.
- Server Side Include (SSI) Injection An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
- Cross Zone Scripting An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
- Cross Site Scripting through Log Files An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
- Command Line Execution through SQL Injection An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
Nessus
NASL family Ubuntu Local Security Checks NASL id UBUNTU_USN-3964-1.NASL description Marcus Brinkmann discovered that GnuPG before 2.2.8 improperly handled certain command line parameters. A remote attacker could use this to spoof the output of GnuPG and cause unsigned e-mail to appear signed. (CVE-2018-12020) It was discovered that python-gnupg incorrectly handled the GPG passphrase. A remote attacker could send a specially crafted passphrase that would allow them to control the output of encryption and decryption operations. (CVE-2019-6690). 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 2020-06-01 modified 2020-06-02 plugin id 124587 published 2019-05-03 reporter Ubuntu Security Notice (C) 2019 Canonical, Inc. / NASL script (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/124587 title Ubuntu 18.04 LTS / 18.10 / 19.04 : python-gnupg vulnerabilities (USN-3964-1) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Ubuntu Security Notice USN-3964-1. 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(124587); script_version("1.3"); script_cvs_date("Date: 2019/09/18 12:31:49"); script_cve_id("CVE-2018-12020", "CVE-2019-6690"); script_xref(name:"USN", value:"3964-1"); script_name(english:"Ubuntu 18.04 LTS / 18.10 / 19.04 : python-gnupg vulnerabilities (USN-3964-1)"); script_summary(english:"Checks dpkg output for updated packages."); script_set_attribute( attribute:"synopsis", value: "The remote Ubuntu host is missing one or more security-related patches." ); script_set_attribute( attribute:"description", value: "Marcus Brinkmann discovered that GnuPG before 2.2.8 improperly handled certain command line parameters. A remote attacker could use this to spoof the output of GnuPG and cause unsigned e-mail to appear signed. (CVE-2018-12020) It was discovered that python-gnupg incorrectly handled the GPG passphrase. A remote attacker could send a specially crafted passphrase that would allow them to control the output of encryption and decryption operations. (CVE-2019-6690). 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/3964-1/" ); script_set_attribute( attribute:"solution", value:"Update the affected python-gnupg and / or python3-gnupg packages." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:L/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:python-gnupg"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-gnupg"); script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts"); script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.10"); script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.04"); script_set_attribute(attribute:"vuln_publication_date", value:"2018/06/08"); script_set_attribute(attribute:"patch_publication_date", value:"2019/05/02"); script_set_attribute(attribute:"plugin_publication_date", value:"2019/05/03"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"Ubuntu Security Notice (C) 2019 Canonical, Inc. / NASL script (C) 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:"^(18\.04|18\.10|19\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 18.04 / 18.10 / 19.04", "Ubuntu " + release); if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu); flag = 0; if (ubuntu_check(osver:"18.04", pkgname:"python-gnupg", pkgver:"0.4.1-1ubuntu1.18.04.1")) flag++; if (ubuntu_check(osver:"18.04", pkgname:"python3-gnupg", pkgver:"0.4.1-1ubuntu1.18.04.1")) flag++; if (ubuntu_check(osver:"18.10", pkgname:"python-gnupg", pkgver:"0.4.1-1ubuntu1.18.10.1")) flag++; if (ubuntu_check(osver:"18.10", pkgname:"python3-gnupg", pkgver:"0.4.1-1ubuntu1.18.10.1")) flag++; if (ubuntu_check(osver:"19.04", pkgname:"python-gnupg", pkgver:"0.4.3-1ubuntu1.19.04.1")) flag++; if (ubuntu_check(osver:"19.04", pkgname:"python3-gnupg", pkgver:"0.4.3-1ubuntu1.19.04.1")) 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, "python-gnupg / python3-gnupg"); }
NASL family SuSE Local Security Checks NASL id OPENSUSE-2019-143.NASL description This update for python-python-gnupg to version 0.4.4 fixes the following issues : Security issue fixed : - CVE-2019-6690: Added a check to disallow certain control characters ( last seen 2020-06-01 modified 2020-06-02 plugin id 121634 published 2019-02-07 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/121634 title openSUSE Security Update : python-python-gnupg (openSUSE-2019-143) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from openSUSE Security Update openSUSE-2019-143. # # The text description of this plugin is (C) SUSE LLC. # include("compat.inc"); if (description) { script_id(121634); script_version("1.4"); script_cvs_date("Date: 2019/04/08 10:48:58"); script_cve_id("CVE-2019-6690"); script_name(english:"openSUSE Security Update : python-python-gnupg (openSUSE-2019-143)"); script_summary(english:"Check for the openSUSE-2019-143 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 python-python-gnupg to version 0.4.4 fixes the following issues : Security issue fixed : - CVE-2019-6690: Added a check to disallow certain control characters ('\r', '\n', NUL) in passphrases (boo#1123498)." ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1123498" ); script_set_attribute( attribute:"solution", value:"Update the affected python-python-gnupg packages." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:L/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:novell:opensuse:python2-python-gnupg"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:python3-python-gnupg"); script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:15.0"); script_set_attribute(attribute:"vuln_publication_date", value:"2019/03/21"); script_set_attribute(attribute:"patch_publication_date", value:"2019/03/23"); script_set_attribute(attribute:"plugin_publication_date", value:"2019/02/07"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof."); 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"); 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 !~ "^(SUSE15\.0)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "15.0", release); if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); flag = 0; if ( rpm_check(release:"SUSE15.0", reference:"python2-python-gnupg-0.4.4-lp150.2.6.1") ) flag++; if ( rpm_check(release:"SUSE15.0", reference:"python3-python-gnupg-0.4.4-lp150.2.6.1") ) 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, "python2-python-gnupg / python3-python-gnupg"); }
NASL family Debian Local Security Checks NASL id DEBIAN_DLA-1675.NASL description Alexander Kjäll and Stig Palmquist discovered a vulnerability in python-gnupg, a wrapper around GNU Privacy Guard. It was possible to inject data through the passphrase property of the gnupg.GPG.encrypt() and gnupg.GPG.decrypt() functions when symmetric encryption is used. The supplied passphrase is not validated for newlines, and the library passes --passphrase-fd=0 to the gpg executable, which expects the passphrase on the first line of stdin, and the ciphertext to be decrypted or plaintext to be encrypted on subsequent lines. By supplying a passphrase containing a newline an attacker can control/modify the ciphertext/plaintext being decrypted/encrypted. For Debian 8 last seen 2020-06-01 modified 2020-06-02 plugin id 122195 published 2019-02-15 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/122195 title Debian DLA-1675-1 : python-gnupg security update code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Debian Security Advisory DLA-1675-1. The text # itself is copyright (C) Software in the Public Interest, Inc. # include("compat.inc"); if (description) { script_id(122195); script_version("1.4"); script_cvs_date("Date: 2019/04/08 10:48:58"); script_cve_id("CVE-2019-6690"); script_name(english:"Debian DLA-1675-1 : python-gnupg security update"); script_summary(english:"Checks dpkg output for the updated packages."); script_set_attribute( attribute:"synopsis", value:"The remote Debian host is missing a security update." ); script_set_attribute( attribute:"description", value: "Alexander Kjäll and Stig Palmquist discovered a vulnerability in python-gnupg, a wrapper around GNU Privacy Guard. It was possible to inject data through the passphrase property of the gnupg.GPG.encrypt() and gnupg.GPG.decrypt() functions when symmetric encryption is used. The supplied passphrase is not validated for newlines, and the library passes --passphrase-fd=0 to the gpg executable, which expects the passphrase on the first line of stdin, and the ciphertext to be decrypted or plaintext to be encrypted on subsequent lines. By supplying a passphrase containing a newline an attacker can control/modify the ciphertext/plaintext being decrypted/encrypted. For Debian 8 'Jessie', this problem has been fixed in version 0.3.6-1+deb8u1. We recommend that you upgrade your python-gnupg packages. NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA 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://lists.debian.org/debian-lts-announce/2019/02/msg00021.html" ); script_set_attribute( attribute:"see_also", value:"https://packages.debian.org/source/jessie/python-gnupg" ); script_set_attribute( attribute:"solution", value:"Upgrade the affected python-gnupg, and python3-gnupg packages." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:L/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:python-gnupg"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:python3-gnupg"); script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0"); script_set_attribute(attribute:"vuln_publication_date", value:"2019/03/21"); script_set_attribute(attribute:"patch_publication_date", value:"2019/02/14"); script_set_attribute(attribute:"plugin_publication_date", value:"2019/02/15"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2019 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:"python-gnupg", reference:"0.3.6-1+deb8u1")) flag++; if (deb_check(release:"8.0", prefix:"python3-gnupg", reference:"0.3.6-1+deb8u1")) 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");
References
- http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00008.html
- http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00058.html
- http://packetstormsecurity.com/files/151341/Python-GnuPG-0.4.3-Improper-Input-Validation.html
- http://www.securityfocus.com/bid/106756
- https://blog.hackeriet.no/cve-2019-6690-python-gnupg-vulnerability/
- https://lists.debian.org/debian-lts-announce/2019/02/msg00021.html
- https://lists.debian.org/debian-lts-announce/2021/12/msg00027.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3WMV6XNPPL3VB3RQRFFOBCJ3AGWC4K47/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W6KYZMN2PWXY4ENZVJUVTGFBVYEVY7II/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X4VFRUG56542LTYK4444TPJBGR57MT25/
- https://pypi.org/project/python-gnupg/#history
- https://seclists.org/bugtraq/2019/Jan/41
- https://usn.ubuntu.com/3964-1/
- http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00008.html
- https://usn.ubuntu.com/3964-1/
- https://seclists.org/bugtraq/2019/Jan/41
- https://pypi.org/project/python-gnupg/#history
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X4VFRUG56542LTYK4444TPJBGR57MT25/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W6KYZMN2PWXY4ENZVJUVTGFBVYEVY7II/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3WMV6XNPPL3VB3RQRFFOBCJ3AGWC4K47/
- https://lists.debian.org/debian-lts-announce/2021/12/msg00027.html
- https://lists.debian.org/debian-lts-announce/2019/02/msg00021.html
- https://blog.hackeriet.no/cve-2019-6690-python-gnupg-vulnerability/
- http://www.securityfocus.com/bid/106756
- http://packetstormsecurity.com/files/151341/Python-GnuPG-0.4.3-Improper-Input-Validation.html
- http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00058.html