Vulnerabilities > CVE-2016-6866 - NULL Pointer Dereference vulnerability in multiple products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
NONE Availability impact
HIGH Summary
slock allows attackers to bypass the screen lock via vectors involving an invalid password hash, which triggers a NULL pointer dereference and crash.
Vulnerable Configurations
Part | Description | Count |
---|---|---|
Application | 3 | |
OS | 2 |
Common Weakness Enumeration (CWE)
Nessus
NASL family Fedora Local Security Checks NASL id FEDORA_2016-7E817CBF55.NASL description This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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 2020-06-05 modified 2016-09-12 plugin id 93423 published 2016-09-12 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/93423 title Fedora 23 : slock (2016-7e817cbf55) code #%NASL_MIN_LEVEL 80502 # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Fedora Security Advisory FEDORA-2016-7e817cbf55. # include("compat.inc"); if (description) { script_id(93423); script_version("2.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2016-6866"); script_xref(name:"FEDORA", value:"2016-7e817cbf55"); script_name(english:"Fedora 23 : slock (2016-7e817cbf55)"); 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: "This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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-2016-7e817cbf55" ); script_set_attribute(attribute:"solution", value:"Update the affected slock package."); 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:fedoraproject:fedora:slock"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:23"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/15"); script_set_attribute(attribute:"patch_publication_date", value:"2016/09/09"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/09/12"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2016-2020 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:"^23([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 23", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC23", reference:"slock-1.3-2.fc23")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_WARNING, 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, "slock"); }
NASL family Fedora Local Security Checks NASL id FEDORA_2016-1B7E66C08B.NASL description This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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 2020-06-05 modified 2016-11-15 plugin id 94779 published 2016-11-15 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/94779 title Fedora 25 : slock (2016-1b7e66c08b) code #%NASL_MIN_LEVEL 80502 # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Fedora Security Advisory FEDORA-2016-1b7e66c08b. # include("compat.inc"); if (description) { script_id(94779); script_version("2.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2016-6866"); script_xref(name:"FEDORA", value:"2016-1b7e66c08b"); script_name(english:"Fedora 25 : slock (2016-1b7e66c08b)"); 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: "This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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-2016-1b7e66c08b" ); script_set_attribute(attribute:"solution", value:"Update the affected slock package."); 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:fedoraproject:fedora:slock"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:25"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/15"); script_set_attribute(attribute:"patch_publication_date", value:"2016/09/05"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/11/15"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2016-2020 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:"^25([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 25", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC25", reference:"slock-1.3-2.fc25")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_WARNING, 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, "slock"); }
NASL family Debian Local Security Checks NASL id DEBIAN_DLA-598.NASL description It was discovered that the slock screen locking tool would segfault when the user last seen 2020-03-17 modified 2016-08-22 plugin id 93053 published 2016-08-22 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/93053 title Debian DLA-598-1 : suckless-tools security update code #%NASL_MIN_LEVEL 80502 # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Debian Security Advisory DLA-598-1. The text # itself is copyright (C) Software in the Public Interest, Inc. # include("compat.inc"); if (description) { script_id(93053); script_version("2.5"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12"); script_cve_id("CVE-2016-6866"); script_name(english:"Debian DLA-598-1 : suckless-tools 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 update." ); script_set_attribute( attribute:"description", value: "It was discovered that the slock screen locking tool would segfault when the user's account had been disabled. slock called crypt(3) and used the return value for strcmp(3) without checking to see if the return value of crypt(3) was a NULL pointer. If the hash returned by (getspnam()->sp_pwdp) was invalid, crypt(3) would return NULL and set errno to EINVAL. This would cause slock to segfault which leaves the machine unprotected. For Debian 7 'Wheezy', this issue has been fixed in suckless-tools version 38-2+deb7u1. We recommend that you upgrade your suckless-tools 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/2016/08/msg00023.html" ); script_set_attribute( attribute:"see_also", value:"https://packages.debian.org/source/wheezy/suckless-tools" ); script_set_attribute( attribute:"solution", value:"Upgrade the affected suckless-tools 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:debian:debian_linux:suckless-tools"); script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:7.0"); script_set_attribute(attribute:"patch_publication_date", value:"2016/08/20"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/08/22"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2016-2020 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:"7.0", prefix:"suckless-tools", reference:"38-2+deb7u1")) 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 family Fedora Local Security Checks NASL id FEDORA_2016-985B68721B.NASL description This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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 2020-06-05 modified 2016-09-12 plugin id 93425 published 2016-09-12 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/93425 title Fedora 24 : slock (2016-985b68721b) code #%NASL_MIN_LEVEL 80502 # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Fedora Security Advisory FEDORA-2016-985b68721b. # include("compat.inc"); if (description) { script_id(93425); script_version("2.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2016-6866"); script_xref(name:"FEDORA", value:"2016-985b68721b"); script_name(english:"Fedora 24 : slock (2016-985b68721b)"); 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: "This release fixes CVE-2016-6866, a crash when verifying a password for a user without a valid shadow hash entry. 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-2016-985b68721b" ); script_set_attribute(attribute:"solution", value:"Update the affected slock package."); 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:fedoraproject:fedora:slock"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:24"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/15"); script_set_attribute(attribute:"patch_publication_date", value:"2016/09/09"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/09/12"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2016-2020 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:"^24([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 24", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC24", reference:"slock-1.3-2.fc24")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_WARNING, 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, "slock"); }
References
- http://www.securityfocus.com/bid/92546
- http://www.openwall.com/lists/oss-security/2016/08/18/24
- http://www.openwall.com/lists/oss-security/2016/08/18/22
- http://s1m0n.dft-labs.eu/files/slock/slock.txt
- http://git.suckless.org/slock/commit/?id=d8bec0f6fdc8a246d78cb488a0068954b46fcb29
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RZPEJQNVODYSI4WQXM5GQKXRO7TPK2VG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2FYPV6QQPPYBL3Z2BYNYEJB67FSC55OR/