Withdrawn by the publisher.

A set of previously unknown vulnerabilities in the DNS forwarder implementation of dnsmasq were disclosed on January 19, 2021. The vulnerabilities are collectively known as DNSpooq. Exploitation of these vulnerabilities could result in remote code execution or denial of service (DoS), or may allow an attacker to more easily forge DNS answers that can poison DNS caches, depending on the specific vulnerability. Multiple Cisco products are affected by these vulnerabilities. Cisco will release software updates that address these vulnerabilities. Any workarounds for a specific Cisco product or service will be documented in the relevant Cisco bugs, which are identified in the Vulnerable Products ["#vp"] section of this advisory. Note: At the time of publication, no Cisco products were found to be affected by the remote code execution and DoS vulnerabilities, which are identified by the following Common Vulnerabilities and Exposures (CVE) IDs: CVE-2020-25681 CVE-2020-25682 CVE-2020-25683 CVE-2020-25687

Affected: CleanStart: dnsmasq

Security vulnerability affects the dnsmasq package. This issue is resolved in later releases. See references for vulnerability details.

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.

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.

Affected devices lack proper address/port check in the DNS reply_query function of dnsmasq.

This could make it easier for remote off-path attackers to forge replies. Affected devices lack query resource name (RRNAME) checks in the DNS reply_query function of dnsmasq.

This could allow a remote attacker to spoof DNS traffic that can lead to DNS cache poisoning. Affected devices lack sufficient entropy in dnsmasq to handle multiple DNS query requests from the same resource name (RRNAME).

This could allow a remote attacker to spoof DNS traffic, using a birthday attack (RFC 5452), than can lead to DNS cache poisoning.

Affected: openEuler:20.03-LTS: dnsmasq, openEuler:20.03-LTS-SP1: dnsmasq

Dnsmasq provides network infrastructure for small networks: DNS, DHCP, router advertisement and network boot. It is designed to be lightweight and have a small footprint, suitable for resource constrained routers and firewalls. It has also been widely used for tethering on smartphones and portable hotspots, and to support virtual networking in virtualisation frameworks. \r\n\r\n Security Fix(es):\r\n\r\n A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.(CVE-2020-25681)\r\n\r\n A flaw was found in dnsmasq. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the…

Security update for dnsmasq

dnsmasq: heap-based buffer overflow in sort_rrset() when DNSSEC is enabled dnsmasq: buffer overflow in extract_name() due to missing length check when DNSSEC is enabled dnsmasq: heap-based buffer overflow with large memcpy in get_rdata() when DNSSEC is enabled dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path attacker dnsmasq: heap-based buffer overflow with large memcpy in sort_rrset() when DNSSEC is enabled

Security update for dnsmasq

Affected: Ubuntu:Pro:14.04:LTS: dnsmasq, Ubuntu:16.04:LTS: dnsmasq, Ubuntu:18.04:LTS: dnsmasq, Ubuntu:20.04:LTS: dnsmasq

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.

Multiple issues have been identified in dnsmasq < 2.83

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in dnsmasq und mehreren Cisco Produkten ausnutzen, um beliebigen Programmcode auszuführen und um den DNS Cache zu manipulieren.