Test ID:	1.3.6.1.4.1.25623.1.1.2.2021.1389
Category:	Huawei EulerOS Local Security Checks
Title:	Huawei EulerOS: Security Advisory for dnsmasq (EulerOS-SA-2021-1389)
Summary:	The remote host is missing an update for the Huawei EulerOS 'dnsmasq' package(s) announced via the EulerOS-SA-2021-1389 advisory.
Description:	Summary: The remote host is missing an update for the Huawei EulerOS 'dnsmasq' package(s) announced via the EulerOS-SA-2021-1389 advisory. Vulnerability Insight: A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the 'Birthday Attacks' section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.(CVE-2020-25686) A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.(CVE-2020-25684) A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.(CVE-2020-25685) A flaw was found in dnsmasq. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause ... [Please see the references for more information on the vulnerabilities] Affected Software/OS: 'dnsmasq' package(s) on Huawei EulerOS Virtualization for ARM 64 3.0.2.0. Solution: Please install the updated package(s). CVSS Score: 8.3 CVSS Vector: AV:N/AC:M/Au:N/C:P/I:P/A:C
Cross-Ref:	Common Vulnerability Exposure (CVE) ID: CVE-2020-25681 Common Vulnerability Exposure (CVE) ID: CVE-2020-25682 Common Vulnerability Exposure (CVE) ID: CVE-2020-25683 Common Vulnerability Exposure (CVE) ID: CVE-2020-25684 Common Vulnerability Exposure (CVE) ID: CVE-2020-25685 Common Vulnerability Exposure (CVE) ID: CVE-2020-25686 Common Vulnerability Exposure (CVE) ID: CVE-2020-25687
Copyright	Copyright (C) 2021 Greenbone Networks GmbH

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