Vulnerabilities > CVE-2016-8637 - Incorrect Permission Assignment for Critical Resource vulnerability in Dracut Project Dracut
Attack vector
LOCAL Attack complexity
LOW Privileges required
LOW Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
A local information disclosure issue was found in dracut before 045 when generating initramfs images with world-readable permissions when 'early cpio' is used, such as when including microcode updates. Local attacker can use this to obtain sensitive information from these files, such as encryption keys or credentials.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Accessing Functionality Not Properly Constrained by ACLs In applications, particularly web applications, access to functionality is mitigated by the authorization framework, whose job it is to map ACLs to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application or can run queries for data that he is otherwise not supposed to.
- Privilege Abuse An adversary is able to exploit features of the target that should be reserved for privileged users or administrators but are exposed to use by lower or non-privileged accounts. Access to sensitive information and functionality must be controlled to ensure that only authorized users are able to access these resources. If access control mechanisms are absent or misconfigured, a user may be able to access resources that are intended only for higher level users. An adversary may be able to exploit this to utilize a less trusted account to gain information and perform activities reserved for more trusted accounts. This attack differs from privilege escalation and other privilege stealing attacks in that the adversary never actually escalates their privileges but instead is able to use a lesser degree of privilege to access resources that should be (but are not) reserved for higher privilege accounts. Likewise, the adversary does not exploit trust or subvert systems - all control functionality is working as configured but the configuration does not adequately protect sensitive resources at an appropriate level.
- Directory Indexing An adversary crafts a request to a target that results in the target listing/indexing the content of a directory as output. One common method of triggering directory contents as output is to construct a request containing a path that terminates in a directory name rather than a file name since many applications are configured to provide a list of the directory's contents when such a request is received. An adversary can use this to explore the directory tree on a target as well as learn the names of files. This can often end up revealing test files, backup files, temporary files, hidden files, configuration files, user accounts, script contents, as well as naming conventions, all of which can be used by an attacker to mount additional attacks.
- Accessing, Modifying or Executing Executable Files An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
- Exploiting Incorrectly Configured Access Control Security Levels An attacker exploits a weakness in the configuration of access controls and is able to bypass the intended protection that these measures guard against and thereby obtain unauthorized access to the system or network. Sensitive functionality should always be protected with access controls. However configuring all but the most trivial access control systems can be very complicated and there are many opportunities for mistakes. If an attacker can learn of incorrectly configured access security settings, they may be able to exploit this in an attack. Most commonly, attackers would take advantage of controls that provided too little protection for sensitive activities in order to perform actions that should be denied to them. In some circumstances, an attacker may be able to take advantage of overly restrictive access control policies, initiating denial of services (if an application locks because it unexpectedly failed to be granted access) or causing other legitimate actions to fail due to security. The latter class of attacks, however, is usually less severe and easier to detect than attacks based on inadequate security restrictions. This attack pattern differs from CAPEC 1, "Accessing Functionality Not Properly Constrained by ACLs" in that the latter describes attacks where sensitive functionality lacks access controls, where, in this pattern, the access control is present, but incorrectly configured.
Nessus
NASL family Fedora Local Security Checks NASL id FEDORA_2016-CC5006BEF7.NASL description - fixed permissions of initramfs file, if microcode is prepended (CVE-2016-8637) 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 2016-11-21 plugin id 95014 published 2016-11-21 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/95014 title Fedora 25 : dracut (2016-cc5006bef7) 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-cc5006bef7. # include("compat.inc"); if (description) { script_id(95014); script_version("3.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2016-8637"); script_xref(name:"FEDORA", value:"2016-cc5006bef7"); script_name(english:"Fedora 25 : dracut (2016-cc5006bef7)"); 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: " - fixed permissions of initramfs file, if microcode is prepended (CVE-2016-8637) 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-cc5006bef7" ); script_set_attribute( attribute:"solution", value:"Update the affected dracut package." ); script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:N"); script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:dracut"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:25"); script_set_attribute(attribute:"vuln_publication_date", value:"2018/08/01"); script_set_attribute(attribute:"patch_publication_date", value:"2016/11/19"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/11/21"); 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:"dracut-044-78.fc25")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_NOTE, 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, "dracut"); }NASL family SuSE Local Security Checks NASL id SUSE_SU-2017-0951-1.NASL description This update for dracut fixes the following issues: Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non security issues fixed : - Remove zlib module as requirement. (bsc#1020063) - Unlimit TaskMax for xfs_repair in emergency shell. (bsc#1019938) - Resolve symbolic links for -i and -k parameters. (bsc#902375) - Enhance purge-kernels script to handle kgraft patches. (bsc#1017141) - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Allow booting on s390x with fips=1 on the kernel command line. (bnc#1021687) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925) - Fix /sbin/installkernel to handle kernel packages built with last seen 2020-06-01 modified 2020-06-02 plugin id 99244 published 2017-04-07 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/99244 title SUSE SLED12 / SLES12 Security Update : dracut (SUSE-SU-2017:0951-1) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from SUSE update advisory SUSE-SU-2017:0951-1. # The text itself is copyright (C) SUSE. # include("compat.inc"); if (description) { script_id(99244); script_version("3.7"); script_cvs_date("Date: 2019/09/11 11:22:15"); script_cve_id("CVE-2016-8637"); script_name(english:"SUSE SLED12 / SLES12 Security Update : dracut (SUSE-SU-2017:0951-1)"); script_summary(english:"Checks rpm output for the updated packages."); script_set_attribute( attribute:"synopsis", value:"The remote SUSE host is missing one or more security updates." ); script_set_attribute( attribute:"description", value: "This update for dracut fixes the following issues: Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non security issues fixed : - Remove zlib module as requirement. (bsc#1020063) - Unlimit TaskMax for xfs_repair in emergency shell. (bsc#1019938) - Resolve symbolic links for -i and -k parameters. (bsc#902375) - Enhance purge-kernels script to handle kgraft patches. (bsc#1017141) - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Allow booting on s390x with fips=1 on the kernel command line. (bnc#1021687) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925) - Fix /sbin/installkernel to handle kernel packages built with 'make bin-rpmpkg'. (bsc#1008648) 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." ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1005410" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1006118" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1007925" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1008340" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1008648" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1017141" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1017695" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1019938" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1020063" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=1021687" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.suse.com/show_bug.cgi?id=902375" ); script_set_attribute( attribute:"see_also", value:"https://www.suse.com/security/cve/CVE-2016-8637/" ); # https://www.suse.com/support/update/announcement/2017/suse-su-20170951-1/ script_set_attribute( attribute:"see_also", value:"http://www.nessus.org/u?7df67fc4" ); script_set_attribute( attribute:"solution", value: "To install this SUSE Security Update use YaST online_update. Alternatively you can run the command listed for your product : SUSE Linux Enterprise Server for Raspberry Pi 12-SP2:zypper in -t patch SUSE-SLE-RPI-12-SP2-2017-547=1 SUSE Linux Enterprise Server 12-SP2:zypper in -t patch SUSE-SLE-SERVER-12-SP2-2017-547=1 SUSE Linux Enterprise Desktop 12-SP2:zypper in -t patch SUSE-SLE-DESKTOP-12-SP2-2017-547=1 OpenStack Cloud Magnum Orchestration 7:zypper in -t patch SUSE-OpenStack-Cloud-Magnum-Orchestration-7-2017-547=1 To bring your system up-to-date, use 'zypper patch'." ); script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:N"); script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C"); script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/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:"exploit_available", value:"false"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:dracut"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:dracut-debuginfo"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:dracut-debugsource"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:dracut-fips"); script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:suse_linux:12"); script_set_attribute(attribute:"vuln_publication_date", value:"2018/08/01"); script_set_attribute(attribute:"patch_publication_date", value:"2017/04/06"); script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/07"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2017-2019 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/cpu", "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, "SUSE"); os_ver = pregmatch(pattern: "^(SLE(S|D)\d+)", string:release); if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "SUSE"); os_ver = os_ver[1]; if (! preg(pattern:"^(SLED12|SLES12)$", string:os_ver)) audit(AUDIT_OS_NOT, "SUSE SLED12 / SLES12", "SUSE " + os_ver); if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if (cpu !~ "^i[3-6]86$" && "x86_64" >!< cpu && "s390x" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "SUSE " + os_ver, cpu); if (cpu >!< "x86_64") audit(AUDIT_ARCH_NOT, "x86_64", cpu); sp = get_kb_item("Host/SuSE/patchlevel"); if (isnull(sp)) sp = "0"; if (os_ver == "SLES12" && (! preg(pattern:"^(2)$", string:sp))) audit(AUDIT_OS_NOT, "SLES12 SP2", os_ver + " SP" + sp); if (os_ver == "SLED12" && (! preg(pattern:"^(2)$", string:sp))) audit(AUDIT_OS_NOT, "SLED12 SP2", os_ver + " SP" + sp); flag = 0; if (rpm_check(release:"SLES12", sp:"2", cpu:"x86_64", reference:"dracut-044-108.1")) flag++; if (rpm_check(release:"SLES12", sp:"2", cpu:"x86_64", reference:"dracut-debuginfo-044-108.1")) flag++; if (rpm_check(release:"SLES12", sp:"2", cpu:"x86_64", reference:"dracut-debugsource-044-108.1")) flag++; if (rpm_check(release:"SLES12", sp:"2", cpu:"x86_64", reference:"dracut-fips-044-108.1")) flag++; if (rpm_check(release:"SLED12", sp:"2", cpu:"x86_64", reference:"dracut-044-108.1")) flag++; if (rpm_check(release:"SLED12", sp:"2", cpu:"x86_64", reference:"dracut-debuginfo-044-108.1")) flag++; if (rpm_check(release:"SLED12", sp:"2", cpu:"x86_64", reference:"dracut-debugsource-044-108.1")) flag++; if (flag) { if (report_verbosity > 0) security_note(port:0, extra:rpm_report_get()); else security_note(0); exit(0); } else { tested = pkg_tests_get(); if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested); else audit(AUDIT_PACKAGE_NOT_INSTALLED, "dracut"); }NASL family Fedora Local Security Checks NASL id FEDORA_2016-94D1C64FE2.NASL description - fixed permissions of initramfs file, if microcode is prepended (CVE-2016-8637) 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 2016-11-10 plugin id 94659 published 2016-11-10 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/94659 title Fedora 24 : dracut (2016-94d1c64fe2) NASL family SuSE Local Security Checks NASL id OPENSUSE-2017-482.NASL description This update for dracut fixes the following issues : Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non security issues fixed : - Remove zlib module as requirement. (bsc#1020063) - Unlimit TaskMax for xfs_repair in emergency shell. (bsc#1019938) - Resolve symbolic links for -i and -k parameters. (bsc#902375) - Enhance purge-kernels script to handle kgraft patches. (bsc#1017141) - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Allow booting on s390x with fips=1 on the kernel command line. (bnc#1021687) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925) - Fix /sbin/installkernel to handle kernel packages built with last seen 2020-06-05 modified 2017-04-19 plugin id 99450 published 2017-04-19 reporter This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/99450 title openSUSE Security Update : dracut (openSUSE-2017-482) NASL family SuSE Local Security Checks NASL id SUSE_SU-2017-2696-1.NASL description This update for dracut fixes the following issues: Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non-security issues fixed : - Skip iBFT discovery for qla4xxx flashnode session. (bsc#935320) - Set MTU and LLADDR for DHCP if specified. (bsc#959803) - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925, bsc#986734, bsc#986838) - Fixed /sbin/installkernel to handle kernel packages built with last seen 2020-06-01 modified 2020-06-02 plugin id 103771 published 2017-10-11 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/103771 title SUSE SLES12 Security Update : dracut (SUSE-SU-2017:2696-1) NASL family SuSE Local Security Checks NASL id OPENSUSE-2017-347.NASL description This update for dracut fixes the following issues : Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non security issues fixed : - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925, bsc#986734, bsc#986838) This update was imported from the SUSE:SLE-12-SP1:Update update project. last seen 2020-06-05 modified 2017-03-17 plugin id 97790 published 2017-03-17 reporter This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/97790 title openSUSE Security Update : dracut (openSUSE-2017-347) NASL family SuSE Local Security Checks NASL id SUSE_SU-2017-0641-1.NASL description This update for dracut fixes the following issues: Security issues fixed : - CVE-2016-8637: When the early microcode loading was enabled during initrd creation, the initrd would be read-only available for all users, allowing local users to retrieve secrets stored in the initial ramdisk. (bsc#1008340) Non security issues fixed : - Allow booting from degraded MD arrays with systemd. (bsc#1017695) - Start multipath services before local-fs-pre.target. (bsc#1005410, bsc#1006118, bsc#1007925, bsc#986734, bsc#986838) 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 2020-06-01 modified 2020-06-02 plugin id 97655 published 2017-03-10 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/97655 title SUSE SLED12 / SLES12 Security Update : dracut (SUSE-SU-2017:0641-1)