Vulnerabilities > CVE-2017-1002101 - Link Following vulnerability in Kubernetes
Attack vector
NETWORK Attack complexity
LOW Privileges required
LOW Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
NONE Summary
In Kubernetes versions 1.3.x, 1.4.x, 1.5.x, 1.6.x and prior to versions 1.7.14, 1.8.9 and 1.9.4 containers using subpath volume mounts with any volume type (including non-privileged pods, subject to file permissions) can access files/directories outside of the volume, including the host's filesystem.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Symlink Attack An attacker positions a symbolic link in such a manner that the targeted user or application accesses the link's endpoint, assuming that it is accessing a file with the link's name. The endpoint file may be either output or input. If the file is output, the result is that the endpoint is modified, instead of a file at the intended location. Modifications to the endpoint file may include appending, overwriting, corrupting, changing permissions, or other modifications. In some variants of this attack the attacker may be able to control the change to a file while in other cases they cannot. The former is especially damaging since the attacker may be able to grant themselves increased privileges or insert false information, but the latter can also be damaging as it can expose sensitive information or corrupt or destroy vital system or application files. Alternatively, the endpoint file may serve as input to the targeted application. This can be used to feed malformed input into the target or to cause the target to process different information, possibly allowing the attacker to control the actions of the target or to cause the target to expose information to the attacker. Moreover, the actions taken on the endpoint file are undertaken with the permissions of the targeted user or application, which may exceed the permissions that the attacker would normally have.
- 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.
- Leverage Executable Code in Non-Executable Files An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
- Manipulating Input to File System Calls An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
Nessus
NASL family Fedora Local Security Checks NASL id FEDORA_2018-9B965C4EED.NASL description Update to 1.10.1 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 2019-01-03 plugin id 120652 published 2019-01-03 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/120652 title Fedora 28 : kubernetes (2018-9b965c4eed) 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-2018-9b965c4eed. # include("compat.inc"); if (description) { script_id(120652); script_version("1.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2017-1002101"); script_xref(name:"FEDORA", value:"2018-9b965c4eed"); script_name(english:"Fedora 28 : kubernetes (2018-9b965c4eed)"); 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: "Update to 1.10.1 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-2018-9b965c4eed" ); script_set_attribute( attribute:"solution", value:"Update the affected kubernetes package." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/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:L/UI:N/S:C/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:fedoraproject:fedora:kubernetes"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:28"); script_set_attribute(attribute:"vuln_publication_date", value:"2018/03/13"); script_set_attribute(attribute:"patch_publication_date", value:"2018/05/16"); script_set_attribute(attribute:"plugin_publication_date", value:"2019/01/03"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2019-2020 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:"^28([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 28", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC28", reference:"kubernetes-1.10.1-0.fc28")) 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, "kubernetes"); }
NASL family Misc. NASL id KUBERNETES_1_9_4_MULTIPLE_VULNERABILITIES.NASL description The version of Kubernetes installed on the remote host is version 1.3.x prior to 1.7.14, 1.8.x prior to 1.8.9 or 1.9.x prior to 1.9.4. It is, therefore, affected by multiple vulnerabilities. - An arbitrary file access vulnerability exists in containers using subpath volume mounts. An authenticated, local attacker can exploit this to access arbitrary files or directories including the host last seen 2020-06-01 modified 2020-06-02 plugin id 124590 published 2019-05-03 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/124590 title Kubernetes 1.3.x < 1.7.14 / 1.8.x < 1.8.9 / 1.9.x < 1.9.4 multiple vulnerabilities NASL family SuSE Local Security Checks NASL id OPENSUSE-2020-554.NASL description This update introduces kubernetes version 1.14.1 and cri-o 1.17.1 to Leap 15.1. last seen 2020-04-30 modified 2020-04-27 plugin id 136011 published 2020-04-27 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/136011 title openSUSE Security Update : kubernetes (openSUSE-2020-554) (Dirty COW) NASL family Red Hat Local Security Checks NASL id REDHAT-RHSA-2018-0475.NASL description An update is now available for Red Hat OpenShift Container Platform 3.7, 3.6, 3.5, 3.4, and 3.3. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenShift Container Platform by Red Hat is the company last seen 2020-06-12 modified 2018-12-04 plugin id 119391 published 2018-12-04 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/119391 title RHEL 7 : Red Hat OpenShift Container Platform (RHSA-2018:0475) NASL family Oracle Linux Local Security Checks NASL id ORACLELINUX_ELSA-2018-4061.NASL description Description of changes: [1.9.1-2.1.5] - Production built 1.9.1-2.1.5 - Fix the upgrade version check - Remove w/a from [Orabug 27125915] [1.9.1-2.1.4.dev] - Make sure worker node upgrade properly - [Orabug 27649898] [1.9.1-2.1.3.dev] - Ensure that the runtime mounts RO volumes read-only [CVE-2017-1002102] - Update Dashboard version to v1.8.3 [CVE-2017-1002102] - Fix nested volume mounts for read-only API data volumes [CVE-2017-1002102] - Fixed kubeadm-setup.sh and kubeadm-registry.sh - Add feature gate for subpath [CVE-2017-1002101] - Add subpath e2e tests [CVE-2017-1002101] - Lock subPath volumes [CVE-2017-1002101] last seen 2020-06-01 modified 2020-06-02 plugin id 108939 published 2018-04-10 reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/108939 title Oracle Linux 7 : kubernetes (ELSA-2018-4061) NASL family Fedora Local Security Checks NASL id FEDORA_2018-16C8FDF9B8.NASL description Update to 1.10.1 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 2018-05-11 plugin id 109704 published 2018-05-11 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/109704 title Fedora 27 : kubernetes (2018-16c8fdf9b8) NASL family Fedora Local Security Checks NASL id FEDORA_2018-2BFBD27A0B.NASL description - Rebase to 3.9 - Security fix for CVE-2017-1002101 and CVE-2017-1002102 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 2019-01-03 plugin id 120316 published 2019-01-03 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/120316 title Fedora 28 : origin (2018-2bfbd27a0b)
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References
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00041.html
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00041.html
- https://access.redhat.com/errata/RHSA-2018:0475
- https://access.redhat.com/errata/RHSA-2018:0475
- https://github.com/bgeesaman/subpath-exploit/
- https://github.com/bgeesaman/subpath-exploit/
- https://github.com/kubernetes/kubernetes/issues/60813
- https://github.com/kubernetes/kubernetes/issues/60813