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 closing HTTP/2 server connection could hang forever waiting for a clean shutdown that was preempted by a subsequent fatal error. This failure mode could be exploited to cause a denial of service.

References: https://go.dev/issue/54658 https://groups.google.com/g/golang-announce/c/x49AQzIVX-s/m/0tgO0pjiBQAJ

Upstream Commits: Master: https://github.com/golang/go/commit/29af494fca8a25d7d46276f6d4835c4dcd09e47d Branch.go1.18 : https://github.com/golang/go/commit/5bc9106458fc07851ac324a4157132a91b1f3479 Branch.go1.19 : https://github.com/golang/go/commit/9cfe4e258b1c9d4a04a42539c21c7bdb2e227824

Arbitrary code execution during build via line directives in cmd/go

Mbed TLS 2.x before 2.28.5 and 3.x before 3.5.0 has a Buffer Overflow.

An attacker can cause excessive memory growth in a Go server accepting HTTP/2 requests. HTTP/2 server connections contain a cache of HTTP header keys sent by the client. While the total number of entries in this cache is capped, an attacker sending very large keys can cause the server to allocate approximately 64 MiB per open connection.

A flaw was found in the Bind package, where the DNSSEC verification code for the EdDSA algorithm leaks memory when there is a signature length mismatch. By spoofing the target resolver with responses that have a malformed EdDSA signature, an attacker can trigger a small memory leak, resulting in crashing the program.

A flaw was found in the Bind package. By spoofing the target resolver with responses that have a malformed ECDSA signature, an attacker can trigger a small memory leak, resulting in crashing the program.

A flaw was found in bind. When flooding the target resolver with special queries, an attacker can significantly impair the resolver's performance, effectively denying legitimate clients access to the DNS resolution service.

A vulnerability was found in Ghostscript. This flaw occurs due to a mishandled permission validation for pipe devices (with the %pipe% prefix or the | pipe character prefix).

CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. The vulnerability allowed to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code. It affects all users using the CKEditor 4 at version < 4.17.0. The problem has been recognized and patched. The fix will be available in version 4.17.0.

Impact

Since Requests v2.3.0, Requests has been vulnerable to potentially leaking Proxy-Authorization headers to destination servers, specifically during redirects to an HTTPS origin. This is a product of how rebuildproxies is used to recompute and reattach the Proxy-Authorization header to requests when redirected. Note this behavior has only been observed to affect proxied requests when credentials are supplied in the URL user information component (e.g. https://username:password@proxy:8080).

Current vulnerable behavior(s):

1. HTTP → HTTPS: leak 2. HTTPS → HTTP: no leak 3. HTTPS → HTTPS: leak 4. HTTP → HTTP: no leak

For HTTP connections sent through the proxy, the proxy will identify the header in the request itself and remove it prior to forwarding to the destination server. However when sent over HTTPS, the Proxy-Authorization header must be sent in the CONNECT request as the proxy has no visibility into further tunneled requests. This results in Requests forwarding the header to the destination server unintentionally, allowing a malicious actor to potentially exfiltrate those credentials.

The reason this currently works for HTTPS connections in Requests is the Proxy-Authorization header is also handled by urllib3 with our usage of the ProxyManager in adapters.py with proxymanagerfor. This will compute the required proxy headers in proxyheaders and pass them to the Proxy Manager, avoiding attaching them directly to the Request object. This will be our preferred option going forward for default usage.

Patches Starting in Requests v2.31.0, Requests will no longer attach this header to redirects with an HTTPS destination. This should have no negative impacts on the default behavior of the library as the proxy credentials are already properly being handled by urllib3's ProxyManager.

For users with custom adapters, this may be potentially breaking if you were already working around this behavior. The previous functionality of rebuildproxies doesn't make sense in any case, so we would encourage any users impacted to migrate any handling of Proxy-Authorization directly into their custom adapter.

Workarounds For users who are not able to update Requests immediately, there is one potential workaround.

You may disable redirects by setting allowredirects to False on all calls through Requests top-level APIs. Note that if you're currently relying on redirect behaviors, you will need to capture the 3xx response codes and ensure a new request is made to the redirect destination. import requests r = requests.get('http://github.com/', allowredirects=False)

Credits

This vulnerability was discovered and disclosed by the following individuals.

Dennis Brinkrolf, Haxolot (https://haxolot.com/) Tobias Funke, (tobiasfunke93@gmail.com)

A security issue was discovered in Kubernetes where a user that can create pods and persistent volumes on Windows nodes may be able to escalate to admin privileges on those nodes. Kubernetes clusters are only affected if they are using an in-tree storage plugin for Windows nodes.

CVE-2022-24834 - A specially crafted Lua script executing in Redis can trigger a heap overflow in the cjson and cmsgpack libraries, and result in heap corruption and potentially remote code execution. The problem exists in all versions of Redis with Lua scripting support, starting from 2.6, and affects only authenticated and authorized users.

https://github.com/redis/redis/security/advisories/GHSA-p8x2-9v9q-c838

EmailValidator and URLValidator were subject to potential regular expression denial of service attack via a very large number of domain name labels of emails and URLs.

Affected versions: Django main development branch, Django 4.2, Django 4.1, Django 3.2

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 RSTSTREAM 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 RSTSTREAM 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 RSTSTREAM 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 RSTSTREAM 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.

.NET and Visual Studio Denial of Service Vulnerability

Netlogon RPC Elevation of Privilege Vulnerability

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability

Windows Kerberos Elevation of Privilege Vulnerability

An out-of-bounds read vulnerability exists due to a boundary error when reading SONMP packets. A remote user can send specially crafted packets to the application, trigger a heap-based buffer overflow read and leak memory values from lldpd application or crash it.

Reference:

https://www.cybersecurity-help.cz/vdb/SB2021111808 https://github.com/lldpd/lldpd/commit/73d42680fce8598324364dbb31b9bc3b8320adf7 https://lldpd.github.io/security.html

A flaw was found in the grafana package. Auth proxy allows authentication of a user by only providing the username (or email) in an X-WEBAUTH-USER HTTP header. The trust assumption is that a front proxy will take care of authentication and that the Grafana server is only publicly reachable with this front proxy.

CVE-2023-45145 - The wrong order of listen(2) and chmod(2) calls creates a race condition that can be used by another process to bypass desired Unix socket permissions on startup.

Upstream have released version 7.0.14/7.2.2 to fix CVE-2023-45145.

Reference: - https://github.com/redis/redis/releases/tag/7.0.14 - https://bugs.mageia.org/32406

A vulnerability was found in Redis. This flaw allows authenticated users to use the HINCRBYFLOAT command to create an invalid hash field that may crash Redis on access.

A security vulnerability was found in zlib. The flaw triggered a heap-based buffer in inflate in the inflate.c function via a large gzip header extra field. This flaw is only applicable in the call inflateGetHeader.

Impact

using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs noticeable slowdown is observed with inputs above 10k characters users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks

Patches The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking.

Workarounds In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities.

References There is an excellent writeup of the issue here: https://github.com/moment/moment/pull/6015#issuecomment-1152961973=

Details The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. moment("(".repeat(500000)) will take a few minutes to process, which is unacceptable.

A use-after-free flaw was found in the Expat package, caused by destruction of a shared DTD in XMLExternalEntityParserCreate in out-of-memory situations. This may lead to availability disruptions.

A flaw in XML parsing could have led to a use-after-free causing a potentially exploitable crash.In official releases of Firefox this vulnerability is mitigated by wasm sandboxing; versions managed by Linux distributions may have other settings.

A vulnerability exists in Async through 3.2.1 for 3.x and through 2.6.3 for 2.x (fixed in 3.2.2 and 2.6.4), which could let a malicious user obtain privileges via the mapValues() method.

A specially crafted web page can abuse this vulnerability to cause memory corruption and potentially arbitrary code execution. A user would need to visit a malicious webpage to trigger this vulnerability.

Reference: https://webkitgtk.org/security/WSA-2023-0009.html#CVE-2023-39928

NGINX Open Source before versions 1.23.2 and 1.22.1, NGINX Open Source Subscription before versions R2 P1 and R1 P1, and NGINX Plus before versions R27 P1 and R26 P1 have a vulnerability in the module ngxhttpmp4module that might allow a local attacker to cause a worker process crash, or might result in worker process memory disclosure by using a specially crafted audio or video file. The issue affects only NGINX products that are built with the module ngxhttpmp4module, when the mp4 directive is used in the configuration file. Further, the attack is possible only if an attacker can trigger processing of a specially crafted audio or video file with the module ngxhttpmp4module.