The various Is methods (IsPrivate, IsLoopback, etc) did not work as expected for IPv4-mapped IPv6 addresses, returning false for addresses which would return true in their traditional IPv4 forms.

Calling Parse on a "// +build" build tag line with deeply nested expressions can cause a panic due to stack exhaustion.

Calling Decoder.Decode on a message which contains deeply nested structures can cause a panic due to stack exhaustion. This is a follow-up to CVE-2022-30635.

The net/http HTTP/1.1 client mishandled the case where a server responds to a request with an "Expect: 100-continue" header with a non-informational (200 or higher) status. This mishandling could leave a client connection in an invalid state, where the next request sent on the connection will fail.

An attacker sending a request to a net/http/httputil.ReverseProxy proxy can exploit this mishandling to cause a denial of service by sending "Expect: 100-continue" requests which elicit a non-informational response from the backend. Each such request leaves the proxy with an invalid connection, and causes one subsequent request using that connection to fail.

The ParseAddressList function incorrectly handles comments (text within parentheses) within display names. Since this is a misalignment with conforming address parsers, it can result in different trust decisions being made by programs using different parsers.

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames.

Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed.

This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send.

The fix sets a limit on the amount of excess header frames we will process before closing a connection.

The filepath package does not recognize paths with a ??\ prefix as special.

On Windows, a path beginning with ??\ is a Root Local Device path equivalent to a path beginning with \?. Paths with a ??\ prefix may be used to access arbitrary locations on the system. For example, the path ??\c:\x is equivalent to the more common path c:\x.

Before fix, Clean could convert a rooted path such as \a..??\b into the root local device path ??\b. Clean will now convert this to .??\b.

Similarly, Join(, ??, b) could convert a seemingly innocent sequence of path elements into the root local device path ??\b. Join will now convert this to .??\b.

In addition, with fix, IsAbs now correctly reports paths beginning with ??\ as absolute, and VolumeName correctly reports the ??\ prefix as a volume name.

UPDATE: Go 1.20.11 and Go 1.21.4 inadvertently changed the definition of the volume name in Windows paths starting with ?, resulting in filepath.Clean(?\c:) returning ?\c: rather than ?\c:\ (among other effects). The previous behavior has been restored.

A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing.

With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection.

This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2.

The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function.

A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing.

With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection.

This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2.

The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function.

Calling Decoder.Decode on a message which contains deeply nested structures can cause a panic due to stack exhaustion. This is a follow-up to CVE-2022-30635.

When parsing a multipart form (either explicitly with Request.ParseMultipartForm or implicitly with Request.FormValue, Request.PostFormValue, or Request.FormFile), limits on the total size of the parsed form were not applied to the memory consumed while reading a single form line. This permits a maliciously crafted input containing very long lines to cause allocation of arbitrarily large amounts of memory, potentially leading to memory exhaustion.

With fix, the ParseMultipartForm function now correctly limits the maximum size of form lines.

Verifying a certificate chain which contains a certificate with an unknown public key algorithm will cause Certificate.Verify to panic.

This affects all crypto/tls clients, and servers that set Config.ClientAuth to VerifyClientCertIfGiven or RequireAndVerifyClientCert. The default behavior is for TLS servers to not verify client certificates.

The archive/zip package's handling of certain types of invalid zip files differs from the behavior of most zip implementations. This misalignment could be exploited to create an zip file with contents that vary depending on the implementation reading the file. The archive/zip package now rejects files containing these errors.

On Windows, The IsLocal function does not correctly detect reserved device names in some cases.

Reserved names followed by spaces, such as "COM1 ", and reserved names "COM" and "LPT" followed by superscript 1, 2, or 3, are incorrectly reported as local.

With fix, IsLocal now correctly reports these names as non-local.

A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body.

A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request.

Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.

Calling any of the Parse functions on Go source code which contains deeply nested literals can cause a panic due to stack exhaustion.

When following an HTTP redirect to a domain which is not a subdomain match or exact match of the initial domain, an http.Client does not forward sensitive headers such as "Authorization" or "Cookie". For example, a redirect from foo.com to www.foo.com will forward the Authorization header, but a redirect to bar.com will not.

A maliciously crafted HTTP redirect could cause sensitive headers to be unexpectedly forwarded.

If errors returned from MarshalJSON methods contain user controlled data, they may be used to break the contextual auto-escaping behavior of the html/template package, allowing for subsequent actions to inject unexpected content into templates.

A security vulnerability has been detected in certain versions of Docker Engine, which could allow an attacker to bypass authorization plugins (AuthZ) under specific circumstances. The base likelihood of this being exploited is low. This advisory outlines the issue, identifies the affected versions, and provides remediation steps for impacted users.

Impact

Using a specially-crafted API request, an Engine API client could make the daemon forward the request or response to an authorization plugin without the body. In certain circumstances, the authorization plugin may allow a request which it would have otherwise denied if the body had been forwarded to it.

A security issue was discovered In 2018, where an attacker could bypass AuthZ plugins using a specially crafted API request. This could lead to unauthorized actions, including privilege escalation. Although this issue was fixed in Docker Engine v18.09.1 in January 2019, the fix was not carried forward to later major versions, resulting in a regression. Anyone who depends on authorization plugins that introspect the request and/or response body to make access control decisions is potentially impacted.

Docker EE v19.03.x and all versions of Mirantis Container Runtime are not vulnerable.

Vulnerability details

• AuthZ bypass and privilege escalation: An attacker could exploit a bypass using an API request with Content-Length set to 0, causing the Docker daemon to forward the request without the body to the AuthZ plugin, which might approve the request incorrectly.
• Initial fix: The issue was fixed in Docker Engine v18.09.1 January 2019..
• Regression: The fix was not included in Docker Engine v19.03 or newer versions. This was identified in April 2024 and patches were released for the affected versions on July 23, 2024. The issue was assigned CVE-2024-41110.

Patches

• docker-ce v27.1.1 containes patches to fix the vulnerability.
• Patches have also been merged into the master, 19.0, 20.0, 23.0, 24.0, 25.0, 26.0, and 26.1 release branches.

Remediation steps

• If you are running an affected version, update to the most recent patched version.
• Mitigation if unable to update immediately:
  • Avoid using AuthZ plugins.
  • Restrict access to the Docker API to trusted parties, following the principle of least privilege.

References

• moby/moby@fc274cd
• moby/moby@a79fabb
• https://www.docker.com/blog/docker-security-advisory-docker-engine-authz-plugin/

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.

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.
• PR libnet: Don't forward to upstream resolvers on internal nw moby/moby#46609 was opened in public to fix this issue, as it was not originally considered to have a security implication.
• 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.

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.

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8694
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8695
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-12912
• https://platypusattack.com/
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=949dd0104c496fa7c14991a23c03c62e44637e71
• https://web.eece.maine.edu/~vweaver/projects/rapl/

A Helm contributor discovered uninitialized variable vulnerability when Helm parses index and plugin yaml files missing expected content.

Impact

When either an index.yaml file or a plugins plugin.yaml file were missing all metadata a panic would occur in Helm.

In the Helm SDK this is found when using the LoadIndexFile or DownloadIndexFile functions in the repo package or the LoadDir function in the plugin package. For the Helm client this impacts functions around adding a repository and all Helm functions if a malicious plugin is added as Helm inspects all known plugins on each invocation.

Patches

This issue has been resolved in Helm v3.14.2.

Workarounds

If a malicious plugin has been added which is causing all Helm client commands to panic, the malicious plugin can be manually removed from the filesystem.

If using Helm SDK versions prior to 3.14.2, calls to affected functions can use recover to catch the panic.

For more information

Helm's security policy is spelled out in detail in our SECURITY document.

Credits

Disclosed by Jakub Ciolek at AlphaSense.

A Helm contributor discovered a path traversal vulnerability when Helm saves a chart including at download time.

Impact

When either the Helm client or SDK is used to save a chart whose name within the Chart.yaml file includes a relative path change, the chart would be saved outside its expected directory based on the changes in the relative path. The validation and linting did not detect the path changes in the name.

Patches

This issue has been resolved in Helm v3.14.1.

Workarounds

Check all charts used by Helm for path changes in their name as found in the Chart.yaml file. This includes dependencies.

Credits

Disclosed by Dominykas Blyžė at Nearform Ltd.

An issue was discovered in Cloud Native Computing Foundation (CNCF) Helm. It displays values of secrets when the --dry-run flag is used. This is a security concern in some use cases, such as a --dry-run call by a CI/CD tool. NOTE: the vendor's position is that this behavior was introduced intentionally, and cannot be removed without breaking backwards compatibility (some users may be relying on these values).

Impact

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.

Workarounds

None.

References

#6703

HTTP/2 Rapid reset attack

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.

Summary

Terrapin is a prefix truncation attack targeting the SSH protocol. More precisely, Terrapin breaks the integrity of SSH's secure channel. By carefully adjusting the sequence numbers during the handshake, an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it.

Mitigations

To mitigate this protocol vulnerability, OpenSSH suggested a so-called "strict kex" which alters the SSH handshake to ensure a Man-in-the-Middle attacker cannot introduce unauthenticated messages as well as convey sequence number manipulation across handshakes.

Warning: To take effect, both the client and server must support this countermeasure.

As a stop-gap measure, peers may also (temporarily) disable the affected algorithms and use unaffected alternatives like AES-GCM instead until patches are available.

Details

The SSH specifications of ChaCha20-Poly1305 ([email protected]) and Encrypt-then-MAC (*[email protected] MACs) are vulnerable against an arbitrary prefix truncation attack (a.k.a. Terrapin attack). This allows for an extension negotiation downgrade by stripping the SSH_MSG_EXT_INFO sent after the first message after SSH_MSG_NEWKEYS, downgrading security, and disabling attack countermeasures in some versions of OpenSSH. When targeting Encrypt-then-MAC, this attack requires the use of a CBC cipher to be practically exploitable due to the internal workings of the cipher mode. Additionally, this novel attack technique can be used to exploit previously unexploitable implementation flaws in a Man-in-the-Middle scenario.

The attack works by an attacker injecting an arbitrary number of SSH_MSG_IGNORE messages during the initial key exchange and consequently removing the same number of messages just after the initial key exchange has concluded. This is possible due to missing authentication of the excess SSH_MSG_IGNORE messages and the fact that the implicit sequence numbers used within the SSH protocol are only checked after the initial key exchange.

In the case of ChaCha20-Poly1305, the attack is guaranteed to work on every connection as this cipher does not maintain an internal state other than the message's sequence number. In the case of Encrypt-Then-MAC, practical exploitation requires the use of a CBC cipher; while theoretical integrity is broken for all ciphers when using this mode, message processing will fail at the application layer for CTR and stream ciphers.

For more details see https://terrapin-attack.com.

Impact

This attack targets the specification of ChaCha20-Poly1305 ([email protected]) and Encrypt-then-MAC (*[email protected]), which are widely adopted by well-known SSH implementations and can be considered de-facto standard. These algorithms can be practically exploited; however, in the case of Encrypt-Then-MAC, we additionally require the use of a CBC cipher. As a consequence, this attack works against all well-behaving SSH implementations supporting either of those algorithms and can be used to downgrade (but not fully strip) connection security in case SSH extension negotiation (RFC8308) is supported. The attack may also enable attackers to exploit certain implementation flaws in a man-in-the-middle (MitM) scenario.

/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.

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8694
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8695
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-12912
• https://platypusattack.com/
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=949dd0104c496fa7c14991a23c03c62e44637e71
• https://web.eece.maine.edu/~vweaver/projects/rapl/

Impact

For Windows users of github.com/cyphar/filepath-securejoin, until v0.2.4 it was possible for certain rootfs and path combinations (in particular, where a malicious Unix-style /-separated unsafe path was used with a Windows-style rootfs path) to result in generated paths that were outside of the provided rootfs.

It is unclear to what extent this has a practical impact on real users, but given the possible severity of the issue we have released an emergency patch release that resolves this issue.

Thanks to @pjbgf for discovering, debugging, and fixing this issue (as well as writing some tests for it).

Patches

c121231e1276e11049547bee5ce68d5a2cfe2d9b is the patch fixing this issue. v0.2.4 contains the fix.

Workarounds

Users could use filepath.FromSlash() on all unsafe paths before passing them to filepath-securejoin.

References

See #9.

The Kubernetes API server component has been found to be vulnerable to a denial of service attack via successful API requests.

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.

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.