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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.022 (81.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 81.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000
Affected products
- Arista Eos
- Thekelleys Dnsmasq
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 32, 33
- Dnsmasq — versions dnsmasq 2.83
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.jsof-tech.com/disclosures/dnspooq/ (Third Party Advisory)
- bugzilla.redhat.com/show_bug.cgi (Patch, Third Party Advisory, Issue Tracking)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202101-17 (vendor-advisory, Third Party Advisory)
- www.debian.org/security/2021/dsa-4844 (vendor-advisory, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- www.arista.com/en/support/advisories-notices/security-advisories/12135-security… (Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108
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.