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.

Undisclosed requests can cause the Traffic Management Microkernel (TMM) to terminate. For the Application Visibility and Reporting module, this may occur when the HTTP Analytics profile with URLs enabled under Collected Entities is configured on a virtual server and the DB variables avr.IncludeServerInURI or avr.CollectOnlyHostnameFromURI are enabled. For BIG-IP Advanced WAF and ASM, this may occur when either a DoS or Bot Defense profile is configured on a virtual server and the DB variables avr.IncludeServerInURI or avr.CollectOnlyHostnameFromURI are enabled.

A SQL injection vulnerability exists in an undisclosed page of the BIG-IP Configuration utility.

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

F5 BIG-IP Configuration utility contains an authentication bypass using an alternate path or channel vulnerability due to undisclosed requests that may allow an unauthenticated attacker with network access to the BIG-IP system through the management port and/or self IP addresses to execute system commands. This vulnerability can be used in conjunction with CVE-2023-46748.

On specific hardware platforms, on BIG-IP versions 16.1.x before 16.1.3.1, 15.1.x before 15.1.7, 14.1.x before 14.1.5.1, and all versions of 13.1.x, while Intel QAT (QuickAssist Technology) and the AES-GCM/CCM cipher is in use, undisclosed conditions can cause BIG-IP to send data unencrypted even with an SSL Profile applied.

When an 'Attack Signature False Positive Mode' enabled security policy is configured on a virtual server, undisclosed requests can cause the bd process to terminate.

In versions 16.1.x before 16.1.3.1, 15.1.x before 15.1.6.1, 14.1.x before 14.1.5.1, and 13.1.x before 13.1.5.1, When the Advanced WAF / ASM module is provisioned, an authenticated remote code execution vulnerability exists in the BIG-IP iControl REST interface.

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3, undisclosed requests to a virtual server may be incorrectly handled by the Traffic Management Microkernel (TMM) URI normalization, which may trigger a buffer overflow, resulting in a DoS attack. In certain situations, it may theoretically allow bypass of URL based access control or remote code execution (RCE). Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3 amd BIG-IQ 7.1.0.x before 7.1.0.3 and 7.0.0.x before 7.0.0.2, the iControl REST interface has an unauthenticated remote command execution vulnerability. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

In BIG-IP versions 15.0.0-15.1.0.3, 14.1.0-14.1.2.5, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, the Traffic Management User Interface (TMUI), also referred to as the Configuration utility, has a Remote Code Execution (RCE) vulnerability in undisclosed pages.

When running in Appliance mode, a highly privileged authenticated attacker with access to SCP and SFTP may be able to bypass Appliance mode restrictions using undisclosed commands.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

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.

A command injection vulnerability exists in iControl REST and the BIG-IP TMOS Shell (tmsh), which may allow an authenticated attacker to execute arbitrary system commands.

When running in Appliance mode, a command injection vulnerability exists in an undisclosed iControl REST and BIG-IP TMOS Shell (tmsh) command that may allow an authenticated attacker with administrator role privileges to execute arbitrary system commands. A successful exploit can allow the attacker to cross a security boundary.

On the BIG-IP system, undisclosed endpoints that contain static non-sensitive information are accessible to an unauthenticated remote attacker through the Configuration utility.

When an iRule using an ILX::call command is configured on a 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.

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.

Under undisclosed traffic conditions along with conditions beyond the attacker's control, hardware systems with a High-Speed Bridge (HSB) and an embedded Packet Velocity Acceleration (ePVA) chip may experience a lockup of the HSB.

When a TCP profile with Multipath TCP (MPTCP) enabled is configured on a virtual server, undisclosed traffic along with conditions beyond the attacker's control can cause the Traffic Management Microkernel (TMM) to terminate.

When DNS cache is configured on a BIG-IP or BIG-IP Next CNF virtual server, undisclosed DNS queries can cause an increase in memory resource utilization.

On BIG-IP systems, undisclosed traffic can cause data corruption and unauthorized data modification in protocols which do not have message integrity protection.

When a virtual server, network address translation (NAT) object, or secure network address translation (SNAT) object uses the embedded Packet Velocity Acceleration (ePVA) feature, and the Auto Last Hop setting is disabled, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. The Auto Last Hop setting is enabled globally by default. For more information about the Auto Last Hop setting, refer to K13876: Overview of the Auto Last Hop setting (15.x - 17.x). To determine which BIG-IP platforms have an ePVA chip, refer to K12837: Overview of the ePVA feature.

When a BIG-IP Advanced WAF or BIG-IP ASM Security Policy is configured with a JSON content profile that has a malformed JSON schema, and the security policy is applied to a virtual server, undisclosed requests can cause the bd process to terminate.

When the database variable tm.tcpudptxchecksum is configured as non-default value Software-only on a BIG-IP system, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate.

A vulnerability exists in the iHealth command that may allow an authenticated attacker with at least a resource administrator role to bypass tmsh restrictions and gain access to a bash shell.  For BIG-IP systems running in Appliance mode, a successful exploit can allow the attacker to cross a security boundary.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

A vulnerability exists in an undisclosed iControl REST and BIG-IP TMOS Shell (tmsh) command that may allow an authenticated attacker with at least resource administrator role to execute arbitrary system commands with higher privileges.  A successful exploit can allow the attacker to cross a security boundary.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

When a BIG IP Advanced WAF or ASM security policy is configured on a virtual server, undisclosed requests can cause the bd process to terminate.

When IPsec is configured on the BIG-IP system, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate.

When using a multi-bladed platform with more than one active blade, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate.