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.

An authenticated SQL injection vulnerability exists in the BIG-IP Configuration utility which

may allow an authenticated attacker with network access to the Configuration utility through the BIG-IP management port and/or self IP addresses to execute arbitrary system commands.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated

An issue was discovered in Python before 3.8.18, 3.9.x before 3.9.18, 3.10.x before 3.10.13, and 3.11.x before 3.11.5. It primarily affects servers (such as HTTP servers) that use TLS client authentication. If a TLS server-side socket is created, receives data into the socket buffer, and then is closed quickly, there is a brief window where the SSLSocket instance will detect the socket as "not connected" and won't initiate a handshake, but buffered data will still be readable from the socket buffer. This data will not be authenticated if the server-side TLS peer is expecting client certificate authentication, and is indistinguishable from valid TLS stream data. Data is limited in size to the amount that will fit in the buffer. (The TLS connection cannot directly be used for data exfiltration because the vulnerable code path requires that the connection be closed on initialization of the SSLSocket.)

A stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Configuration utility that allows an attacker to run JavaScript in the context of the currently logged-in user. This vulnerability is due to an incomplete fix for CVE-2024-31156 https://my.f5.com/manage/s/article/K000138636 .

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

When Diffie-Hellman (DH) group Elliptic Curve Cryptography (ECC) Brainpool curves are configured in an SSL profile's Cipher Rule or Cipher Group, and that profile is applied to a virtual server, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate.

ISC BIND is vulnerable to a denial of service, caused by an error when preparing an NSEC3 closest encloser proof. By flooding the target resolver with queries, a remote attacker could exploit this vulnerability to cause CPU exhaustion on a DNSSEC-validating resolver.

A stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Configuration utility that allows an attacker to run JavaScript in the context of the currently logged-in user.

BIG-IP monitor functionality may allow an attacker to bypass access control restrictions, regardless of the port lockdown settings.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

When SIP session Application Level Gateway mode (ALG) profile with Passthru Mode enabled and SIP router ALG profile are configured on a Message Routing type virtual server, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

When a BIG-IP message routing profile is configured on a virtual server, undisclosed traffic can cause an increase in memory resource utilization.

When SNMP v1 or v2c are disabled on the BIG-IP system, undisclosed requests can cause an increase in memory resource utilization.