The version of dnsmasq installed on the remote host is prior to 2.76-16. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2021-1587 advisory.

  - 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 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)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Detections

Analytics

Amazon Linux 2 : dnsmasq (ALAS-2021-1587)

low Nessus Plugin ID 145454

Version 1.3