A incomplete list of disallowed inputs vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.2, FortiWeb 7.6.0 through 7.6.5, FortiWeb 7.4 all versions, FortiWeb 7.2 all versions, FortiWeb 7.0 all versions may allow attacker to improper access control via <insert attack vector here>

A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate within a set time period.

A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiADC 7.6.0 through 7.6.1, FortiADC 7.4.0 through 7.4.6, FortiADC 7.2.0 through 7.2.7, FortiADC 7.1.0 through 7.1.4, FortiADC 7.0 all versions, FortiADC 6.2 all versions, FortiADC 6.1 all versions, FortiADC 6.0 all versions, FortiADC 5.4 all versions, FortiADC 5.3 all versions, FortiADC 5.2 all versions, FortiADC 5.1 all versions, FortiADC 5.0 all versions, FortiADC 4.8 all versions, FortiADC 4.7 all versions, FortiADC 4.6 all versions, FortiADC 4.5 all versions, FortiADC 4.4 all versions, FortiADC 4.3 all versions, FortiADC 4.2 all versions, FortiADC 4.1 all versions, FortiADC 4.0 all versions, FortiADC 3.2 all versions, FortiADC 3.1 all versions, FortiADC 3.0 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>

A buffer copy without checking size of input ('classic buffer overflow') vulnerability in Fortinet FortiClientWindows 7.4.0 through 7.4.3, FortiClientWindows 7.2.0 through 7.2.11 may allow an unauthenticated attacker in a position to alter or craft DNS responses to the targeted host to execute arbitrary code via malicious packets.

A allocation of resources without limits or throttling vulnerability in Fortinet FortiOS 7.6.0 through 7.6.6, FortiOS 7.4 all versions, FortiOS 7.2 all versions may allow attacker to denial of service via <insert attack vector here>

A authentication bypass using an alternate path or channel vulnerability in Fortinet FortiManager 7.6.1, FortiManager 7.4.3 through 7.4.5, FortiManager 7.2.5 through 7.2.9, FortiManager Cloud 7.6.1, FortiManager Cloud 7.4.3 through 7.4.5, FortiManager Cloud 7.2.5 through 7.2.9 may allow attacker to improper access control via <insert attack vector here>

A Stack-based Buffer Overflow vulnerability [CWE-121] vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6 may allow an unauthenticated attacker who can bypass stack protection and ASLR to execute arbitrary code or commands in the context of the WAD daemon via crafted sockets, only if the explicit proxy is configured with Kerberos authentication and SOCKS enabled.

A server-side request forgery (ssrf) vulnerability in Fortinet FortiSIEM 7.5.0, FortiSIEM 7.4.0 through 7.4.2, FortiSIEM 7.3.0 through 7.3.5, FortiSIEM 7.2 all versions, FortiSIEM 7.1 all versions, FortiSIEM 7.0 all versions, FortiSIEM 6.7 all versions, FortiSIEM 6.6 all versions, FortiSIEM 6.5 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>

An Improper Authentication vulnerability [CWE-287] vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.2, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11, FortiWeb 7.2.0 through 7.2.12, FortiWeb 7.0.0 through 7.0.12 may allow a remote unauthenticated attacker to login into the Fortiweb GUI/CLI with a random username and password

A session fixation vulnerability [CWE-384] in FortiOS may allow an unauthenticated attacker to hijack user session via a phishing SAML authentication link.

An improper neutralization of special elements used in an OS command ('OS Command Injection') vulnerability [CWE-78] vulnerability in Fortinet FortiSIEM 7.3.0 through 7.3.1, FortiSIEM 7.2.0 through 7.2.5, FortiSIEM 7.1.0 through 7.1.7, FortiSIEM 7.0.0 through 7.0.3, FortiSIEM 6.7.0 through 6.7.9, FortiSIEM 6.6 all versions, FortiSIEM 6.5 all versions, FortiSIEM 6.4 all versions, FortiSIEM 6.3 all versions, FortiSIEM 6.2 all versions, FortiSIEM 6.1 all versions, FortiSIEM 5.4 all versions, FortiSIEM 5.3 all versions, FortiSIEM 5.2 all versions, FortiSIEM 5.1 all versions, FortiSIEM 5.0 all versions, FortiSIEM 4.10 all versions, FortiSIEM 4.9 all versions, FortiSIEM 4.7 all versions allows an unauthenticated attacker to execute unauthorized code or commands via crafted CLI requests.

A Heap-based Buffer Overflow vulnerability [CWE-122] vulnerability in Fortinet FortiClientWindows 7.4.0 through 7.4.3, FortiClientWindows 7.2.0 through 7.2.8 may allow an authenticated local IPSec user to execute arbitrary code or commands via "fortips74.sys". The attacker would need to bypass the Windows heap integrity protections

A Default Configuration vulnerability in FortiOS may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server.

A Improper Access Control in Fortinet FortiOS 6.0.2, 5.6.7 and before, FortiADC 6.1.0, 6.0.0 to 6.0.1, 5.4.0 to 5.4.4 allows attacker to obtain the LDAP server login credentials configured in FortiGate via pointing a LDAP server connectivity test request to a rogue LDAP server instead of the configured one.

An improper neutralization of special elements used in an SQL command ('SQL injection') [CWE-89] in FortiAnalyzer, FortiAnalyzer Cloud, FortiManager and FortiManager Cloud may allow an authenticated privileged attacker to execute unauthorized code or commands via crafted requests.

A client-side enforcement of server-side security [CWE-602] vulnerability in FortiManager and FortiAnalyzer may allow a remote attacker with low privileges to access a privileged web console via client side code execution.

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 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com MACs) are vulnerable against an arbitrary prefix truncation attack (a.k.a. Terrapin attack). This allows for an extension negotiation downgrade by stripping the SSHMSGEXTINFO sent after the first message after SSHMSGNEWKEYS, 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 SSHMSGIGNORE 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 SSHMSGIGNORE 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 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com), 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.

An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below may result in a user being able to log in successfully without being prompted for the second factor of authentication (FortiToken) if they changed the case of their username.

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.

A improper limitation of a pathname to a restricted directory ('path traversal') vulnerability in Fortinet FortiOS 7.6.0 through 7.6.6, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions, FortiPAM 1.8.0, FortiPAM 1.7.0 through 1.7.2, FortiPAM 1.6 all versions, FortiPAM 1.5 all versions, FortiPAM 1.4 all versions, FortiPAM 1.3 all versions, FortiPAM 1.2 all versions, FortiPAM 1.1 all versions, FortiPAM 1.0 all versions, FortiProxy 7.6.0 through 7.6.5, FortiProxy 7.4 through 7.4.13, FortiProxy 7.2 all versions, FortiProxy 7.0 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>

A buffer over-read vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions, FortiProxy 7.6.0 through 7.6.5, FortiProxy 7.4.0 through 7.4.13, FortiProxy 7.2 all versions, FortiProxy 7.0 all versions may allow attacker to information disclosure via <insert attack vector here>

A stack-based buffer overflow vulnerability in Fortinet FortiOS 7.4.0 through 7.4.1, FortiOS 7.2 all versions, FortiPAM 1.8.0 through 1.8.2, FortiPAM 1.7 all versions, FortiPAM 1.6 all versions, FortiPAM 1.5 all versions, FortiPAM 1.4 all versions, FortiPAM 1.3 all versions, FortiPAM 1.2 all versions, FortiPAM 1.1 all versions, FortiPAM 1.0 all versions, FortiProxy 7.4.0 through 7.4.13, FortiProxy 7.2 all versions may allow a privileged authenticated attacker who can bypass stack protection and ASLR to execute arbitrary code or commands via crafted HTTP requests.

An Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability [CWE-79] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.6, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiPAM 1.8.0, FortiPAM 1.7 all versions, FortiPAM 1.6 all versions, FortiPAM 1.5 all versions, FortiPAM 1.4 all versions, FortiPAM 1.3 all versions, FortiPAM 1.2 all versions, FortiPAM 1.1 all versions, FortiPAM 1.0 all versions, FortiProxy 7.4.0 through 7.4.3, FortiProxy 7.2.0 through 7.2.9 may allow an authenticated remote user to execute code or commands via crafted requests.

An Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability [CWE-113] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.4, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions may allow an attacker in possession of a valid web filter override token to inject arbitrary headers via tricking a user into clicking on a crafted link.

An Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability [CWE-113] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.4, FortiOS 7.4 all versions, FortiOS 7.2 all versions, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions may allow an attacker able to intercept and modify a user's captive portal authentication request to inject arbitrary headers via crafted HTTP requests.

A buffer over-read vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions may allow an authenticated remote attacker to return a portion of device memory in the redirect response via submitting a specially crafted request.

An Internal Asset Exposed to Unsafe Debug Access Level or State vulnerability [CWE-1244] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.2, FortiOS 7.4.0 through 7.4.7, FortiOS 7.2.0 through 7.2.10, FortiOS 7.0.0 through 7.0.16, FortiOS 6.4 all versions, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4.0 through 7.4.10, FortiProxy 7.2.0 through 7.2.14, FortiProxy 7.0 all versions may allow an authenticated admin to execute lua scripts via crafted CLI commands.

An improper verification of cryptographic signature vulnerability in Fortinet FortiWeb 8.0.0, FortiWeb 7.6.0 through 7.6.4, FortiWeb 7.4.0 through 7.4.9 may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.

A improper verification of cryptographic signature vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4.0 through 7.4.10, FortiProxy 7.2.0 through 7.2.14, FortiProxy 7.0.0 through 7.0.21, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.

An Unchecked Return Value vulnerability [CWE-252] in Fortinet FortiOS version 7.6.0 through 7.6.3 and before 7.4.8 API allows an authenticated user to cause a Null Pointer Dereference, crashing the http daemon via a specialy crafted request.