Vulnerability in Arista Eos

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.

EPSS: 0.022 (80.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-25685?
CVE-2020-25685 is a low-severity vulnerability in Arista Eos, classified under Inadequate Encryption Strength. CVSS score: 3.7/10. Published 2021-01-20.
How severe is CVE-2020-25685?
Low severity. CVSS v3 base score is 3.7 out of 10.
Is CVE-2020-25685 known to be exploited?
22 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.