CVE-2020-25685

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.

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.

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 base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.(CVE-2020-25682)\r\n\r\n 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. A remote attacker, who can create valid DNS replies, could use this flaw 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 get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.(CVE-2020-25683)\r\n\r\n A flaw was found in dnsmasq. 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)\r\n\r\n A flaw was found in dnsmasq. 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…

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.

Multiples vulnerabilities have been discovered in dnsmasq up to version 2.82:

• subtle errors in dnsmasq's protections against cache-poisoning attacks (CVE-2020-25684, CVE-2020-25685 and CVE-2020-25686)
• buffer overflow in dnsmasq's DNSSEC code (CVE-2020-25681, CVE-2020-25682, CVE-2020-25683 and CVE-2020-25687)

This update for dnsmasq fixes the following issues:

• bsc#1177077: Fixed DNSpooq vulnerabilities

• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks.

• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.

• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update was imported from the SUSE:SLE-15-SP1:Update update project.

This update for dnsmasq fixes the following issues:

• bsc#1177077: Fixed DNSpooq vulnerabilities

• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks.

• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.

• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update was imported from the SUSE:SLE-15-SP1:Update update project.

These are all security issues fixed in the dnsmasq-2.86-1.1 package on the GA media of openSUSE Tumbleweed.

This update for dnsmasq fixes the following issues:

• bsc#1177077: Fixed DNSpooq vulnerabilities
• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks.
• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.
• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update for dnsmasq fixes the following issues:

• bsc#1177077: Fixed DNSpooq vulnerabilities

• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks.

• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.

• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update for dnsmasq fixes the following issues:

• bsc#1177077: Fixed DNSpooq vulnerabilities

• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks.

• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.

• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update for dnsmasq fixes the following issues:

• CVE-2019-14834: Fixed a memory leak which could have allowed to remote attackers to cause denial of service via DHCP response creation (bsc#1154849)
• bsc#1177077: Fixed DNSpooq vulnerabilities
• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache poisoning attacks.
• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled.
• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076)

This update for dnsmasq fixes the following issues:

Security issues fixed:

• CVE-2020-25684, CVE-2020-25685, CVE-2020-25686: Fixed multiple Cache Poisoning attacks (bsc#1177077).
• CVE-2020-25681, CVE-2020-25682, CVE-2020-25683, CVE-2020-25687: Fixed multiple potential Heap-based overflows when DNSSEC is enabled (bsc#1177077).

Non-security issue fixed:

• Retry query to other servers on receipt of SERVFAIL rcode (bsc#1176076).

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled memory when sorting RRsets. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25681, CVE-2020-25687)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled extracting certain names. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25682, CVE-2020-25683)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented address/port checks. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25684)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented query resource name checks. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25685)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled multiple query requests for the same resource name. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25686)

It was discovered that Dnsmasq incorrectly handled memory during DHCP response creation. A remote attacker could possibly use this issue to cause Dnsmasq to consume resources, leading to a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2019-14834)