OpenSSH Dropbear 漏洞 CVE-2023-48795

[zhng920823]

https://nvd.nist.gov/vuln/detail/CVE-2023-48795

The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in [email protected] and (if CBC is used) the [email protected] MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD before 1.3.8b (and before1.3.9rc2), ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2 6401, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust; and there could be effects on Bitvise SSH through 9.31.

[RangerWolf]

NVD score not yet provided.

要是真的，估计运维又要痛苦一波了

[tool2d]

看了一下，严格来说是 https://terrapin-attack.com/ 这个网页。

其实没大问题，这是属于中间人攻击，破坏性很低。

除非是电信运营商想要黑你的 SSH 服务器，一般黑客没办法。

[zhng920823]

@tool2d #2 是的，对普通人威胁不大，但是对高价值目标还是有威胁性的。

[acess]

https://github.com/mkj/dropbear/blob/41a6abca32dd3da273152c07dbded41fb6d70726/CHANGES#L17

At present the flaw does not seem to reduce Dropbear's security (the only packet affected would be a server-sig-algs extension, which is used for compatibility not security).

dropbear 官方还没修

而且 dropbear 好像并没有真正受到这个漏洞的影响