You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
In Docker 19.03.x before 19.03.1 linked against the GNU C Library (aka glibc), code injection can occur when the nsswitch facility dynamically loads a library inside a chroot that contains the contents of the container.
Insertion of Sensitive Information into Log File
Affected range
<18.09.8
Fixed version
18.09.8
CVSS Score
7.5
CVSS Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Description
In Docker CE and EE before 18.09.8 (as well as Docker EE before 17.06.2-ee-23 and 18.x before 18.03.1-ee-10), Docker Engine in debug mode may sometimes add secrets to the debug log. This applies to a scenario where docker stack deploy is run to redeploy a stack that includes (non external) secrets. It potentially applies to other API users of the stack API if they resend the secret.
Insufficient Verification of Data Authenticity
Affected range
<24.0.9
Fixed version
24.0.9
CVSS Score
6.9
CVSS Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:L
Description
The classic builder cache system is prone to cache poisoning if the image is built FROM scratch.
Also, changes to some instructions (most important being HEALTHCHECK and ONBUILD) would not cause a cache miss.
An attacker with the knowledge of the Dockerfile someone is using could poison their cache by making them pull a specially crafted image that would be considered as a valid cache candidate for some build steps.
For example, an attacker could create an image that is considered as a valid cache candidate for:
FROM scratch
MAINTAINER Pawel
when in fact the malicious image used as a cache would be an image built from a different Dockerfile.
In the second case, the attacker could for example substitute a different HEALTCHECK command.
Impact
23.0+ users are only affected if they explicitly opted out of Buildkit (DOCKER_BUILDKIT=0 environment variable) or are using the /build API endpoint (which uses the classic builder by default).
All users on versions older than 23.0 could be impacted. An example could be a CI with a shared cache, or just a regular Docker user pulling a malicious image due to misspelling/typosquatting.
Image build API endpoint (/build) and ImageBuild function from github.com/docker/docker/client is also affected as it the uses classic builder by default.
Patches
Patches are included in Moby releases:
v25.0.2
v24.0.9
v23.0.10
Workarounds
Use --no-cache or use Buildkit if possible (DOCKER_BUILDKIT=1, it's default on 23.0+ assuming that the buildx plugin is installed).
Use Version = types.BuilderBuildKit or NoCache = true in ImageBuildOptions for ImageBuild call.
Incorrect Authorization
Affected range
<20.10.18
Fixed version
20.10.18
CVSS Score
6.3
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Description
Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where supplementary groups are not set up properly. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases, potentially gaining access to sensitive information or gaining the ability to execute code in that container. This bug is fixed in Moby (Docker Engine) 20.10.18. Users should update to this version when it is available. Running containers should be stopped and restarted for the permissions to be fixed. For users unable to upgrade, this problem can be worked around by not using the "USER $USERNAME" Dockerfile instruction. Instead by calling ENTRYPOINT ["su", "-", "user"] the supplementary groups will be set up properly.
Thanks to Steven Murdoch for reporting this issue.
Impact
If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases, potentially gaining access to sensitive information or gaining the ability to execute code in that container.
Patches
This bug is fixed in Moby (Docker Engine) 20.10.18. Users should update to this version when it is available.
Workarounds
This problem can be worked around by not using the "USER $USERNAME" Dockerfile instruction. Instead by calling ENTRYPOINT ["su", "-", "user"] the supplementary groups will be set up properly.
Moby is an open source container framework originally developed by Docker Inc. as Docker. It is a key component of Docker Engine, Docker Desktop, and other distributions of container tooling or runtimes. As a batteries-included container runtime, Moby comes with a built-in networking implementation that enables communication between containers, and between containers and external resources.
Moby's networking implementation allows for creating and using many networks, each with their own subnet and gateway. This feature is frequently referred to as custom networks, as each network can have a different driver, set of parameters, and thus behaviors. When creating a network, the --internal flag is used to designate a network as internal. The internal attribute in a docker-compose.yml file may also be used to mark a network internal, and other API clients may specify the internal parameter as well.
When containers with networking are created, they are assigned unique network interfaces and IP addresses (typically from a non-routable RFC 1918 subnet). The root network namespace (hereafter referred to as the 'host') serves as a router for non-internal networks, with a gateway IP that provides SNAT/DNAT to/from container IPs.
Containers on an internal network may communicate between each other, but are precluded from communicating with any networks the host has access to (LAN or WAN) as no default route is configured, and firewall rules are set up to drop all outgoing traffic. Communication with the gateway IP address (and thus appropriately configured host services) is possible, and the host may communicate with any container IP directly.
In addition to configuring the Linux kernel's various networking features to enable container networking, dockerd directly provides some services to container networks. Principal among these is serving as a resolver, enabling service discovery (looking up other containers on the network by name), and resolution of names from an upstream resolver.
When a DNS request for a name that does not correspond to a container is received, the request is forwarded to the configured upstream resolver (by default, the host's configured resolver). This request is made from the container network namespace: the level of access and routing of traffic is the same as if the request was made by the container itself.
As a consequence of this design, containers solely attached to internal network(s) will be unable to resolve names using the upstream resolver, as the container itself is unable to communicate with that nameserver. Only the names of containers also attached to the internal network are able to be resolved.
Many systems will run a local forwarding DNS resolver, typically present on a loopback address (127.0.0.0/8), such as systemd-resolved or dnsmasq. Common loopback address examples include 127.0.0.1 or 127.0.0.53. As the host and any containers have separate loopback devices, a consequence of the design described above is that containers are unable to resolve names from the host's configured resolver, as they cannot reach these addresses on the host loopback device.
To bridge this gap, and to allow containers to properly resolve names even when a local forwarding resolver is used on a loopback address, dockerd will detect this scenario and instead forward DNS requests from the host/root network namespace. The loopback resolver will then forward the requests to its configured upstream resolvers, as expected.
Impact
Because dockerd will forward DNS requests to the host loopback device, bypassing the container network namespace's normal routing semantics entirely, internal networks can unexpectedly forward DNS requests to an external nameserver.
By registering a domain for which they control the authoritative nameservers, an attacker could arrange for a compromised container to exfiltrate data by encoding it in DNS queries that will eventually be answered by their nameservers. For example, if the domain evil.example was registered, the authoritative nameserver(s) for that domain could (eventually and indirectly) receive a request for this-is-a-secret.evil.example.
Docker Desktop is not affected, as Docker Desktop always runs an internal resolver on a RFC 1918 address.
Patches
Moby releases 26.0.0-rc3, 25.0.5 (released) and 23.0.11 (to be released) are patched to prevent forwarding DNS requests from internal networks.
Workarounds
Run containers intended to be solely attached to internal networks with a custom upstream address (--dns argument to docker run, or API equivalent), which will force all upstream DNS queries to be resolved from the container network namespace.
Background
yair zak originally reported this issue to the Docker security team.
The official documentation claims that "the --internal flag that will completely isolate containers on a network from any communications external to that network," which necessitated this advisory and CVE.
Incorrect Permission Assignment for Critical Resource
Affected range
<20.10.14
Fixed version
20.10.14
CVSS Score
5.9
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Description
Impact
A bug was found in Moby (Docker Engine) where containers were incorrectly started with non-empty inheritable Linux process capabilities, creating an atypical Linux environment and enabling programs with inheritable file capabilities to elevate those capabilities to the permitted set during execve(2). Normally, when executable programs have specified permitted file capabilities, otherwise unprivileged users and processes can execute those programs and gain the specified file capabilities up to the bounding set. Due to this bug, containers which included executable programs with inheritable file capabilities allowed otherwise unprivileged users and processes to additionally gain these inheritable file capabilities up to the container's bounding set. Containers which use Linux users and groups to perform privilege separation inside the container are most directly impacted.
This bug did not affect the container security sandbox as the inheritable set never contained more capabilities than were included in the container's bounding set.
Patches
This bug has been fixed in Moby (Docker Engine) 20.10.14. Users should update to this version as soon as possible. Running containers should be stopped, deleted, and recreated for the inheritable capabilities to be reset.
This fix changes Moby (Docker Engine) behavior such that containers are started with a more typical Linux environment. Refer to capabilities(7) for a description of how capabilities work. Note that permitted file capabilities continue to allow for privileges to be raised up to the container's bounding set and that processes may add capabilities to their own inheritable set up to the container's bounding set per the rules described in the manual page. In all cases the container's bounding set provides an upper bound on the capabilities that can be assumed and provides for the container security sandbox.
Workarounds
The entrypoint of a container can be modified to use a utility like capsh(1) to drop inheritable capabilities prior to the primary process starting.
Email us at [email protected] if you think you’ve found a security bug
Improper Preservation of Permissions
Affected range
<20.10.9
Fixed version
20.10.9
CVSS Score
5.9
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Description
Impact
A bug was found in Moby (Docker Engine) where the data directory (typically /var/lib/docker) contained subdirectories with insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files.
Patches
This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers should be stopped and restarted for the permissions to be fixed.
Workarounds
Limit access to the host to trusted users. Limit access to host volumes to trusted containers.
Credits
The Moby project would like to thank Joan Bruguera for responsibly disclosing this issue in accordance with the Moby security policy.
For more information
If you have any questions or comments about this advisory:
Email us at [email protected] if you think you’ve found a security bug
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected range
<19.03.9
Fixed version
19.03.9
CVSS Score
5.3
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Description
util/binfmt_misc/check.go in Builder in Docker Engine before 19.03.9 calls os.OpenFile with a potentially unsafe qemu-check temporary pathname, constructed with an empty first argument in an ioutil.TempDir call.
Affected range
<20.10.11+incompatible
Fixed version
20.10.11+incompatible
Description
Moby (Docker Engine) is vulnerable to Ambiguous OCI manifest parsing in github.com/docker/docker
Affected range
<20.10.11
Fixed version
20.10.11
Description
Impact
In the OCI Distribution Specification version 1.0.0 and prior and in the OCI Image Specification version 1.0.1 and prior, manifest and index documents are ambiguous without an accompanying Content-Type HTTP header. Versions of Moby (Docker Engine) prior to 20.10.11 treat the Content-Type header as trusted and deserialize the document according to that header. If the Content-Type header changed between pulls of the same ambiguous document (with the same digest), the document may be interpreted differently, meaning that the digest alone is insufficient to unambiguously identify the content of the image.
Patches
This issue has been fixed in Moby (Docker Engine) 20.10.11. Image pulls for manifests that contain a “manifests” field or indices which contain a “layers” field are rejected.
Intel's RAPL (Running Average Power Limit) feature, introduced by the Sandy Bridge microarchitecture, provides software insights into hardware energy consumption. To facilitate this, Intel introduced the powercap framework in Linux kernel 3.13, which reads values via relevant MSRs (model specific registers) and provides unprivileged userspace access via sysfs. As RAPL is an interface to access a hardware feature, it is only available when running on bare metal with the module compiled into the kernel.
By 2019, it was realized that in some cases unprivileged access to RAPL readings could be exploited as a power-based side-channel against security features including AES-NI (potentially inside a SGX enclave) and KASLR (kernel address space layout randomization). Also known as the PLATYPUS attack, Intel assigned CVE-2020-8694 and CVE-2020-8695, and AMD assigned CVE-2020-12912.
Several mitigations were applied; Intel reduced the sampling resolution via a microcode update, and the Linux kernel prevents access by non-root users since 5.10. However, this kernel-based mitigation does not apply to many container-based scenarios:
Unless using user namespaces, root inside a container has the same level of privilege as root outside the container, but with a slightly more narrow view of the system
sysfs is mounted inside containers read-only; however only read access is needed to carry out this attack on an unpatched CPU
While this is not a direct vulnerability in container runtimes, defense in depth and safe defaults are valuable and preferred, especially as this poses a risk to multi-tenant container environments running directly on affected hardware. This is provided by masking /sys/devices/virtual/powercap in the default mount configuration, and adding an additional set of rules to deny it in the default AppArmor profile.
While sysfs is not the only way to read from the RAPL subsystem, other ways of accessing it require additional capabilities such as CAP_SYS_RAWIO which is not available to containers by default, or perf paranoia level less than 1, which is a non-default kernel tunable.
A bug was found in Moby (Docker Engine) where attempting to copy files using docker cp into a specially-crafted container can result in Unix file permission changes for existing files in the host’s filesystem, widening access to others. This bug does not directly allow files to be read, modified, or executed without an additional cooperating process.
Patches
This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers do not need to be restarted.
Workarounds
Ensure you only run trusted containers.
Credits
The Moby project would like to thank Lei Wang and Ruizhi Xiao for responsibly disclosing this issue in accordance with the Moby security policy.
For more information
If you have any questions or comments about this advisory:
Email us at [email protected] if you think you’ve found a security bug
Exposure of Sensitive Information to an Unauthorized Actor
Affected range
<=20.10.19
Fixed version
20.10.20
Description
Description
Moby is the open source Linux container runtime and set of components used to build a variety of downstream container runtimes, including Docker CE, Mirantis Container Runtime (formerly Docker EE), and Docker Desktop. Moby allows for building container images using a set of build instructions (usually named and referred to as a "Dockerfile"), and a build context, which is not unlike the CWD in which the Dockerfile instructions are executed.
Containers may be built using a variety of tools and build backends available in the Moby ecosystem; in all cases, builds may not include files outside of the build context (such as using absolute or relative-parent paths). This is enforced through both checks in the build backends, and the containerization of the build process itself.
Versions of Git where CVE-2022-39253 is present and exploited by a malicious repository, when used in combination with Moby, are subject to an unexpected inclusion of arbitrary filesystem paths in the build context, without any visible warning to the user.
This issue was originally reported by Wenxiang Qian of Tencent Blade Team, and the root-cause analysis was performed by Cory Snider of Mirantis, with assistance from Bjorn Neergaard of the same. The issue was then reported to the Git project, and Taylor Blau led the process resolving the root issue in Git.
Impact
This vulnerability originates in Git, but can be used to violate assumptions that may have security implications for users of Moby and related components. Users may rely on the fact that a build context ensures that outside files cannot be referenced or incorporated using multiple enforcement mechanisms, or expect a warning if this does not hold true. A maliciously crafted Git repository exploiting CVE-2022-39253 can violate this assumption, and potentially include sensitive files that are subsequently uploaded to a container image repository, or disclosed by code inside the resulting container image.
As this issue cannot be triggered remotely, except by users who already have full control over the daemon through the API, and it requires exploiting a vulnerability in Git by convincing a user to build a maliciously crafted repository, the impact in Moby is considered low.
Patches
Moby 20.10.20, and Mirantis Container Runtime (formerly Docker Enterprise Edition) 20.10.14 will contain mitigations for CVE-2022-39253 when a Git clone is performed by Moby components (on either the daemon or API client side). However, as these mitigations only apply to certain scenarios (build of git+<protocol>://... URL contexts) and cannot protect against a malicious repository already on disk, users should update to a version of Git containing patches for CVE-2022-39253 on all their systems running both API clients and daemons.
Specifically, patches in Moby (including patches incorporated from BuildKit) protect against the following:
docker build with the legacy builder (e.g. DOCKER_BUILDKIT unset or set to 0) of a Git URL context. Note that depending on available API versions and the CLI version, the Git clone operation can take place on either the client or the daemon side. Both must be updated (or have Git updated) to fully protect this build method.
docker build with the BuildKit builder (e.g. DOCKER_BUILDKIT=1) of a Git URL context.
docker buildx build with BUILDKIT_CONTEXT_KEEP_GIT_DIR=1 of a Git URL context.
Patches in BuildKit incorporated into Docker Compose protect against CVE-2022-39253 during Compose-driven builds of Git URL contexts.
Patches in Moby and related projects such as BuildKit, the Docker CLI, and Docker Compose cannot fully protect against CVE-2022-39253, as it may be triggered by a malicious repository already on disk that a unpatched Git client has interacted with (specifically, commands that check out submodules such as git clone --recursive, git submodule update, etc. may have already triggered the Git vulnerability).
Workarounds
While this behavior is unexpected and undesirable, and has resulted in this security advisory, users should keep in mind that building a container entails arbitrary code execution. Users should not build a repository/build context they do not trust, as containerization cannot protect against all possible attacks.
When building with BuildKit (e.g. docker buildx build or docker build with DOCKER_BUILDKIT=1), this issue cannot be exploited unless --build-arg BUILDKIT_CONTEXT_KEEP_GIT_DIR=1 was also passed, as by default BuildKit will discard the .git directory of a Git URL context immediately after cloning and checking out the repository.
For more information
If you have any questions or comments about this advisory:
Containers launched through containerd’s CRI implementation on Linux systems which use the SELinux security module and containerd versions since v1.5.0 can cause arbitrary files and directories on the host to be relabeled to match the container process label through the use of specially-configured bind mounts in a hostPath volume. This relabeling elevates permissions for the container, granting full read/write access over the affected files and directories. Kubernetes and crictl can both be configured to use containerd’s CRI implementation.
If you are not using containerd’s CRI implementation (through one of the mechanisms described above), you are not affected by this issue.
Patches
This bug has been fixed in containerd 1.5.9. Because file labels persist independently of containerd, users should both update to these versions as soon as they are released and validate that all files on their host are correctly labeled.
Workarounds
Ensure that no sensitive files or directories are used as a hostPath volume source location. Policy enforcement mechanisms such a Kubernetes Pod Security Policy AllowedHostPaths may be specified to limit the files and directories that can be bind-mounted to containers.
For more information
If you have any questions or comments about this advisory:
Exposure of Sensitive Information to an Unauthorized Actor
Affected range
>=1.5.0 <1.5.10
Fixed version
1.5.10
CVSS Score
7.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Description
Impact
A bug was found in containerd where containers launched through containerd’s CRI implementation with a specially-crafted image configuration could gain access to read-only copies of arbitrary files and directories on the host. This may bypass any policy-based enforcement on container setup (including a Kubernetes Pod Security Policy) and expose potentially sensitive information. Kubernetes and crictl can both be configured to use containerd’s CRI implementation.
Patches
This bug has been fixed in containerd 1.6.1, 1.5.10 and 1.4.13. Users should update to these versions to resolve the issue.
Workarounds
Ensure that only trusted images are used.
Credits
The containerd project would like to thank Felix Wilhelm of Google Project Zero for responsibly disclosing this issue in accordance with the containerd security policy.
For more information
If you have any questions or comments about this advisory:
Supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases and potentially escalate privileges in the container. Uses of the containerd client library may also have improperly setup supplementary groups.
Affected range
<1.5.18
Fixed version
1.5.18
Description
Supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases and potentially escalate privileges in the container. Uses of the containerd client library may also have improperly setup supplementary groups.
Affected range
<1.5.18
Fixed version
1.5.18
Description
Supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases and potentially escalate privileges in the container. Uses of the containerd client library may also have improperly setup supplementary groups.
Affected range
<1.5.18
Fixed version
1.5.18
Description
Supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases and potentially escalate privileges in the container. Uses of the containerd client library may also have improperly setup supplementary groups.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected range
>=1.5.0 <1.5.7
Fixed version
1.5.7
CVSS Score
5.9
CVSS Vector
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Description
Impact
A bug was found in containerd where container root directories and some plugins had insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files.
Patches
This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability.
Workarounds
Limit access to the host to trusted users. Update directory permission on container bundles directories.
For more information
If you have any questions or comments about this advisory:
A bug was found in containerd's CRI implementation where a user can exhaust memory on the host. In the CRI stream server, a goroutine is launched to handle terminal resize events if a TTY is requested. If the user's process fails to launch due to, for example, a faulty command, the goroutine will be stuck waiting to send without a receiver, resulting in a memory leak. Kubernetes and crictl can both be configured to use containerd's CRI implementation and the stream server is used for handling container IO.
Patches
This bug has been fixed in containerd 1.6.12 and 1.5.16. Users should update to these versions to resolve the issue.
Workarounds
Ensure that only trusted images and commands are used and that only trusted users have permissions to execute commands in running containers.
For more information
If you have any questions or comments about this advisory:
When importing an OCI image, there was no limit on the number of bytes read for certain files. A maliciously crafted image with a large file where a limit was not applied could cause a denial of service.
Patches
This bug has been fixed in containerd 1.6.18 and 1.5.18. Users should update to these versions to resolve the issue.
Workarounds
Ensure that only trusted images are used and that only trusted users have permissions to import images.
Credits
The containerd project would like to thank David Korczynski and Adam Korczynski of ADA Logics for responsibly disclosing this issue in accordance with the containerd security policy during a security fuzzing audit sponsored by CNCF.
For more information
If you have any questions or comments about this advisory:
A bug was found in containerd's CRI implementation where programs inside a container can cause the containerd daemon to consume memory without bound during invocation of the ExecSync API. This can cause containerd to consume all available memory on the computer, denying service to other legitimate workloads. Kubernetes and crictl can both be configured to use containerd's CRI implementation; ExecSync may be used when running probes or when executing processes via an "exec" facility.
Patches
This bug has been fixed in containerd 1.6.6 and 1.5.13. Users should update to these versions to resolve the issue.
Workarounds
Ensure that only trusted images and commands are used.
The containerd project would like to thank David Korczynski and Adam Korczynski of ADA Logics for responsibly disclosing this issue in accordance with the containerd security policy during a security audit sponsored by CNCF and facilitated by OSTIF.
For more information
If you have any questions or comments about this advisory:
A bug was found in containerd where supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases, potentially gaining access to sensitive information or gaining the ability to execute code in that container.
Downstream applications that use the containerd client library may be affected as well.
Patches
This bug has been fixed in containerd v1.6.18 and v.1.5.18. Users should update to these versions and recreate containers to resolve this issue. Users who rely on a downstream application that uses containerd's client library should check that application for a separate advisory and instructions.
Workarounds
Ensure that the "USER $USERNAME" Dockerfile instruction is not used. Instead, set the container entrypoint to a value similar to ENTRYPOINT ["su", "-", "user"] to allow su to properly set up supplementary groups.
/sys/devices/virtual/powercap accessible by default to containers
Intel's RAPL (Running Average Power Limit) feature, introduced by the Sandy Bridge microarchitecture, provides software insights into hardware energy consumption. To facilitate this, Intel introduced the powercap framework in Linux kernel 3.13, which reads values via relevant MSRs (model specific registers) and provides unprivileged userspace access via sysfs. As RAPL is an interface to access a hardware feature, it is only available when running on bare metal with the module compiled into the kernel.
By 2019, it was realized that in some cases unprivileged access to RAPL readings could be exploited as a power-based side-channel against security features including AES-NI (potentially inside a SGX enclave) and KASLR (kernel address space layout randomization). Also known as the PLATYPUS attack, Intel assigned CVE-2020-8694 and CVE-2020-8695, and AMD assigned CVE-2020-12912.
Several mitigations were applied; Intel reduced the sampling resolution via a microcode update, and the Linux kernel prevents access by non-root users since 5.10. However, this kernel-based mitigation does not apply to many container-based scenarios:
Unless using user namespaces, root inside a container has the same level of privilege as root outside the container, but with a slightly more narrow view of the system
sysfs is mounted inside containers read-only; however only read access is needed to carry out this attack on an unpatched CPU
While this is not a direct vulnerability in container runtimes, defense in depth and safe defaults are valuable and preferred, especially as this poses a risk to multi-tenant container environments. This is provided by masking /sys/devices/virtual/powercap in the default mount configuration, and adding an additional set of rules to deny it in the default AppArmor profile.
While sysfs is not the only way to read from the RAPL subsystem, other ways of accessing it require additional capabilities such as CAP_SYS_RAWIO which is not available to containers by default, or perf paranoia level less than 1, which is a non-default kernel tunable.
Access of Resource Using Incompatible Type ('Type Confusion')
Affected range
>=1.5.0 <1.5.8
Fixed version
1.5.8
CVSS Score
3
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N
Description
Impact
In the OCI Distribution Specification version 1.0.0 and prior and in the OCI Image Specification version 1.0.1 and prior, manifest and index documents are ambiguous without an accompanying Content-Type HTTP header. Versions of containerd prior to 1.4.12 and 1.5.8 treat the Content-Type header as trusted and deserialize the document according to that header. If the Content-Type header changed between pulls of the same ambiguous document (with the same digest), the document may be interpreted differently, meaning that the digest alone is insufficient to unambiguously identify the content of the image.
Patches
This issue has been fixed in containerd 1.4.12 and 1.5.8. Image pulls for manifests that contain a “manifests” field or indices which contain a “layers” field are rejected.
A bug was found in containerd where containers were incorrectly started with non-empty inheritable Linux process capabilities, creating an atypical Linux environment and enabling programs with inheritable file capabilities to elevate those capabilities to the permitted set during execve(2). Normally, when executable programs have specified permitted file capabilities, otherwise unprivileged users and processes can execute those programs and gain the specified file capabilities up to the bounding set. Due to this bug, containers which included executable programs with inheritable file capabilities allowed otherwise unprivileged users and processes to additionally gain these inheritable file capabilities up to the container's bounding set. Containers which use Linux users and groups to perform privilege separation inside the container are most directly impacted.
This bug did not affect the container security sandbox as the inheritable set never contained more capabilities than were included in the container's bounding set.
Patches
This bug has been fixed in containerd 1.5.11 and 1.6.2. Users should update to these versions as soon as possible. Running containers should be stopped, deleted, and recreated for the inheritable capabilities to be reset.
This fix changes containerd behavior such that containers are started with a more typical Linux environment. Refer to capabilities(7) for a description of how capabilities work. Note that permitted file capabilities continue to allow for privileges to be raised up to the container's bounding set and that processes may add capabilities to their own inheritable set up to the container's bounding set per the rules described in the manual page. In all cases the container's bounding set provides an upper bound on the capabilities that can be assumed and provides for the container security sandbox.
Workarounds
The entrypoint of a container can be modified to use a utility like capsh(1) to drop inheritable capabilities prior to the primary process starting.
For more information
If you have any questions or comments about this advisory:
httpTokenCacheKey uses path.Base to extract the expected HTTP-01 token value to lookup in the DirCache implementation. On Windows, path.Base acts differently to filepath.Base, since Windows uses a different path separator (\ vs. /), allowing a user to provide a relative path, i.e. .well-known/acme-challenge/....\asd becomes ....\asd. The extracted path is then suffixed with +http-01, joined with the cache directory, and opened.
Since the controlled path is suffixed with +http-01 before opening, the impact of this is significantly limited, since it only allows reading arbitrary files on the system if and only if they have this suffix.
Use of a Broken or Risky Cryptographic Algorithm
Affected range
<0.0.0-20220314234659-1baeb1ce4c0b
Fixed version
0.0.0-20220314234659-1baeb1ce4c0b
CVSS Score
7.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Description
The golang.org/x/crypto/ssh package before 0.0.0-20220314234659-1baeb1ce4c0b for Go allows an attacker to crash a server in certain circumstances involving AddHostKey.
Affected range
<0.0.0-20211202192323-5770296d904e
Fixed version
0.0.0-20211202192323-5770296d904e
CVSS Score
7.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Description
The x/crypto/ssh package before 0.0.0-20211202192323-5770296d904e of golang.org/x/crypto allows an unauthenticated attacker to panic an SSH server. When using AES-GCM or ChaCha20Poly1305, consuming a malformed packet which contains an empty plaintext causes a panic.
In net/http in Go before 1.18.6 and 1.19.x before 1.19.1, attackers can cause a denial of service because an HTTP/2 connection can hang during closing if shutdown were preempted by a fatal error.
Affected range
<0.0.0-20211209124913-491a49abca63
Fixed version
0.0.0-20211209124913-491a49abca63
Description
An attacker can cause unbounded memory growth in servers accepting HTTP/2 requests.
In affected releases of gRPC-Go, it is possible for an attacker to send HTTP/2 requests, cancel them, and send subsequent requests, which is valid by the HTTP/2 protocol, but would cause the gRPC-Go server to launch more concurrent method handlers than the configured maximum stream limit.
Patches
This vulnerability was addressed by #6703 and has been included in patch releases: 1.56.3, 1.57.1, 1.58.3. It is also included in the latest release, 1.59.0.
Along with applying the patch, users should also ensure they are using the grpc.MaxConcurrentStreams server option to apply a limit to the server's resources used for any single connection.
The HTTP/2 protocol allows clients to indicate to the server that a previous stream should be canceled by sending a RST_STREAM frame. The protocol does not require the client and server to coordinate the cancellation in any way, the client may do it unilaterally. The client may also assume that the cancellation will take effect immediately when the server receives the RST_STREAM frame, before any other data from that TCP connection is processed.
Abuse of this feature is called a Rapid Reset attack because it relies on the ability for an endpoint to send a RST_STREAM frame immediately after sending a request frame, which makes the other endpoint start working and then rapidly resets the request. The request is canceled, but leaves the HTTP/2 connection open.
The HTTP/2 Rapid Reset attack built on this capability is simple: The client opens a large number of streams at once as in the standard HTTP/2 attack, but rather than waiting for a response to each request stream from the server or proxy, the client cancels each request immediately.
The ability to reset streams immediately allows each connection to have an indefinite number of requests in flight. By explicitly canceling the requests, the attacker never exceeds the limit on the number of concurrent open streams. The number of in-flight requests is no longer dependent on the round-trip time (RTT), but only on the available network bandwidth.
In a typical HTTP/2 server implementation, the server will still have to do significant amounts of work for canceled requests, such as allocating new stream data structures, parsing the query and doing header decompression, and mapping the URL to a resource. For reverse proxy implementations, the request may be proxied to the backend server before the RST_STREAM frame is processed. The client on the other hand paid almost no costs for sending the requests. This creates an exploitable cost asymmetry between the server and the client.
Multiple software artifacts implementing HTTP/2 are affected. This advisory was originally ingested from the swift-nio-http2 repo advisory and their original conent follows.
swift-nio-http2 specific advisory
swift-nio-http2 is vulnerable to a denial-of-service vulnerability in which a malicious client can create and then reset a large number of HTTP/2 streams in a short period of time. This causes swift-nio-http2 to commit to a large amount of expensive work which it then throws away, including creating entirely new Channels to serve the traffic. This can easily overwhelm an EventLoop and prevent it from making forward progress.
swift-nio-http2 1.28 contains a remediation for this issue that applies reset counter using a sliding window. This constrains the number of stream resets that may occur in a given window of time. Clients violating this limit will have their connections torn down. This allows clients to continue to cancel streams for legitimate reasons, while constraining malicious actors.
Systems that run distribution built after a specific commit running on memory-restricted environments can suffer from denial of service by a crafted malicious /v2/_catalog API endpoint request.
Patches
Upgrade to at least 2.8.2-beta.1 if you are running v2.8.x release. If you use the code from the main branch, update at least to the commit after f55a6552b006a381d9167e328808565dd2bf77dc.
Workarounds
There is no way to work around this issue without patching. Restrict access to the affected API endpoint: see the recommendations section.
References
/v2/_catalog endpoint accepts a parameter to control the maximum amount of records returned (query string: n).
When not given the default n=100 is used. The server trusts that n has an acceptable value, however when using a
maliciously large value, it allocates an array/slice of n of strings before filling the slice with data.
This behaviour was introduced ~7yrs ago [1].
Recommendation
The /v2/_catalog endpoint was designed specifically to do registry syncs with search or other API systems. Such an endpoint would create a lot of load on the backend system, due to overfetch required to serve a request in certain implementations.
Because of this, we strongly recommend keeping this API endpoint behind heightened privilege and avoiding leaving it exposed to the internet.
For more information
If you have any questions or comments about this advisory:
Access of Resource Using Incompatible Type ('Type Confusion')
Affected range
<2.8.0
Fixed version
2.8.0
CVSS Score
3
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N
Description
Impact
Systems that rely on digest equivalence for image attestations may be vulnerable to type confusion.
Patches
Upgrade to at least v2.8.0-beta.1 if you are running v2.x release. If you use the code from the main branch, update at least to the commit after b59a6f827947f9e0e67df0cfb571046de4733586.
Workarounds
There is no way to work around this issue without patching.
References
Due to an oversight in the OCI Image Specification that removed the embedded mediaType field from manifests, a maliciously crafted OCI Container Image can cause registry clients to parse the same image in two different ways without modifying the image’s digest by modifying the Content-Type header returned by a registry. This can invalidate a common pattern of relying on container image digests for equivalence.
For more information
If you have any questions or comments about this advisory:
Go before 1.17.10 and 1.18.x before 1.18.2 has Incorrect Privilege Reporting in syscall. When called with a non-zero flags parameter, the Faccessat function could incorrectly report that a file is accessible.
The protojson.Unmarshal function can enter an infinite loop when unmarshaling certain forms of invalid JSON. This condition can occur when unmarshaling into a message which contains a google.protobuf.Any value, or when the UnmarshalOptions.DiscardUnknown option is set.
go-retryablehttp prior to 0.7.7 did not sanitize urls when writing them to its log file. This could lead to go-retryablehttp writing sensitive HTTP basic auth credentials to its log file. This vulnerability, CVE-2024-6104, was fixed in go-retryablehttp 0.7.7.
Access of Resource Using Incompatible Type ('Type Confusion')
Affected range
<1.0.2
Fixed version
1.0.2
CVSS Score
3
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N
Description
Impact
In the OCI Image Specification version 1.0.1 and prior, manifest and index documents are not self-describing and documents with a single digest could be interpreted as either a manifest or an index.
Patches
The Image Specification will be updated to recommend that both manifest and index documents contain a mediaType field to identify the type of document.
Release v1.0.2 includes these updates.
Workarounds
Software attempting to deserialize an ambiguous document may reject the document if it contains both “manifests” and “layers” fields or “manifests” and “config” fields.
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This PR contains the following updates:
0.19.0->0.19.1Warning
Some dependencies could not be looked up. Check the Dependency Dashboard for more information.
Release Notes
marcosnils/bin (marcosnils/bin)
v0.19.1Compare Source
Changelog
4ae9285add support for arm64 architectureConfiguration
📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).
🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.
♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.
🔕 Ignore: Close this PR and you won't be reminded about this update again.
This PR has been generated by Renovate Bot.