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.

Threat-Mapped Scoring

Score: 0.0

Priority: Unclassified

EPSS

Score: 0.00368
Percentile: 0.5793

CVSS Scoring

Mapped CWE(s)

• CWE-326 : Inadequate Encryption Strength

All CAPEC(s)

CAPEC(s) with Mapped TTPs

Mapped ATT&CK TTPs

• T1110 : Brute Force
  Kill Chain: credential-access

Malware

APTs Threat Group Associations

Campaigns

Affected Products

• cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
• cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*
• cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*
• cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*
• cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*
• cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*

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