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=========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2024.2592 putty security update 26 April 2024 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: putty Publisher: Debian Operating System: Debian GNU/Linux Resolution: Patch/Upgrade CVE Names: CVE-2023-48795 CVE-2019-17069 CVE-2020-14002 CVE-2021-36367 Original Bulletin: https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html Comment: CVSS (Max): 8.1 CVE-2021-36367 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N) CVSS Source: NIST Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N - --------------------------BEGIN INCLUDED TEXT-------------------- - ------------------------------------------------------------------------- Debian LTS Advisory DLA-3794-1 debian-lts@lists.debian.org https://www.debian.org/lts/security/ Bastien RoucariA s April 25, 2024 https://wiki.debian.org/LTS - ------------------------------------------------------------------------- Package : putty Version : 0.74-1+deb11u1~deb10u1 CVE ID : CVE-2019-17069 CVE-2020-14002 CVE-2021-36367 CVE-2023-48795 Debian Bug : 990901 Putty, a Telnet/SSH client for X, was vulnerable. CVE-2019-17069 PuTTY allowed remote SSH-1 servers to cause a denial of service by accessing freed memory locations via an SSH1_MSG_DISCONNECT message. CVE-2020-14002 PuTTY had an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allowed man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). CVE-2021-36367 PuTTY proceeded with establishing an SSH session even if it has never sent a substantive authentication response. This made it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user). CVE-2023-48795 PuTTY was vulnerable to Terrapin attack. The SSH transport protocol with certain OpenSSH extensions, allowed 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. 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 chacha20-poly1305 and (if CBC is used) the -etm MAC algorithms. For Debian 10 buster, this problem has been fixed in version 0.74-1+deb11u1~deb10u1. We recommend that you upgrade your putty packages. For the detailed security status of putty please refer to its security tracker page at: https://security-tracker.debian.org/tracker/putty Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS - --------------------------END INCLUDED TEXT---------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. ===========================================================================