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Message-ID: <c6f17dee-ca33-7d57-ef89-0707d3189826@nic.cz> Date: Thu, 9 Aug 2018 08:06:36 +0200 From: Petr Špaček <petr.spacek@....cz> To: oss-security@...ts.openwall.com Subject: Knot Resolver 2.4.1 security release Hello, this is copy of e-mail for distros@ mailing list. Fixed version 2.4.1 is already available from https://secure.nic.cz/files/knot-resolver/ I apologize for delay between release and this post. Petr Špaček @ CZ.NIC -------- Forwarded Message -------- Subject: [vs] Knot Resolver 2.4.1 security release + CVE request Date: Wed, 1 Aug 2018 16:47:14 +0200 From: Petr Špaček <petr.spacek@....cz> Organization: CZ.NIC To: distros@...openwall.org Hello, this is pre-release advisory about bugs affecting security of Knot Resolver (a DNS resolver by CZ.NIC). Impact ====== Under certain circumstances this bug allows an attacker to hijack DNS domains. Unembargo date ============== Thursday 2nd August 2018 12:00 (noon) GMT Fixes ===== Minimal patch on top of version 2.4.0 is in attached fix.patch. The second file hardening.patch which provides additional hardening (defense in depth but not strictly necessary). We will be releasing version 2.4.1 with other fixes as well. If you are interested we could provide encrypted tarball with 2.4.1 sooner so you can build version with other fixes as well, just let me know. CVE assignment request ====================== [Requestors emails address (required)]: petr.spacek@....cz [I confirm that this CVE is for an Open Source software component/library/etc. (required)]: yes [I confirm that I have read the CVE Terms of Use and agree to them (required)]: yes [Vendor/Project of the product (required)]: CZ.NIC [Affected product name (required)]: Knot Resolver [Product URL (required)]: https://www.knot-resolver.cz/ [Affected version (required)]: Knot Resolver <= 2.4.0 [Fixed version (optional)]: Knot Resolver 2.4.1 [Vulnerability type (required)]: CWE-20: Improper Input Validation [Affected component (required)]: resolver [Impact of exploitation (required)]: Under certain circumstances this bug allows an attacker to hijack DNS domains. [Description of vulnerability]: Improper input validation bug in DNS resolver component of Knot Resolver allows remote attacker to poison cache. To execute this attack the attacker has to have: + access to rogue authoritative server and + ability to trigger query from resolver under attack to authoritative server under attacker's control For successful exploitation the data used to poison cache need to match certain criteria which we decided not to disclose at the moment. Please note that "classical" DNS answer spoofing is going to be very hard because Knot Resolver randomizes ports, query ID, and query name capitalization - i.e. plain Kaminsky attack will be difficult. This is why attacker needs to control an authoritative server. Attack Vector (AV): Network Attack Complexity (AC): Low Privileges Required (PR): None User Interaction (UI): None Scope (S): Unchanged Confidentiality (C): None Integrity (I): High Availability (A): None Technical Details: CWE-20 Acknowledgment: CZ.NIC would like to thank Marek Vavrusa for reporting this issue. [Reference URL 1 (required)]: https://www.knot-resolver.cz/2018-08-02-knot-resolver-2.4.1.html Thank you for processing this. -- Petr Špaček @ CZ.NIC View attachment "fix.patch" of type "text/x-patch" (1348 bytes) View attachment "hardening.patch" of type "text/x-patch" (2741 bytes)
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