CVE-2020-25685

2021-01-2000:00:00

CWE-326

redhat

www.cve.org

6.2 Medium

AI Score

Confidence

Low

0.012 Low

EPSS

Percentile

85.0%

JSON

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.

CNA Affected

[
  {
    "vendor": "n/a",
    "product": "dnsmasq",
    "versions": [
      {
        "version": "dnsmasq 2.83",
        "status": "affected"
      }
    ]
  }
]