Slackware-14.0 ChangeLog (2021-02-09)

Tue Feb 9 20:43:33 UTC 2021

  • patches/packages/dnsmasq-2.84-i486-1_slack14.0.txz
    This update fixes bugs and remotely exploitable security issues:
    Use the values of –min-port and –max-port in outgoing
    TCP connections to upstream DNS servers.
    Fix a remote buffer overflow problem in the DNSSEC code. Any
    dnsmasq with DNSSEC compiled in and enabled is vulnerable to this,
    referenced by CVE-2020-25681, CVE-2020-25682, CVE-2020-25683
    Be sure to only accept UDP DNS query replies at the address
    from which the query was originated. This keeps as much entropy
    in the {query-ID, random-port} tuple as possible, to help defeat
    cache poisoning attacks. Refer: CVE-2020-25684.
    Use the SHA-256 hash function to verify that DNS answers
    received are for the questions originally asked. This replaces
    the slightly insecure SHA-1 (when compiled with DNSSEC) or
    the very insecure CRC32 (otherwise). Refer: CVE-2020-25685.
    Handle multiple identical near simultaneous DNS queries better.
    Previously, such queries would all be forwarded
    independently. This is, in theory, inefficent but in practise
    not a problem, _except_ that is means that an answer for any
    of the forwarded queries will be accepted and cached.
    An attacker can send a query multiple times, and for each repeat,
    another {port, ID} becomes capable of accepting the answer he is
    sending in the blind, to random IDs and ports. The chance of a
    succesful attack is therefore multiplied by the number of repeats
    of the query. The new behaviour detects repeated queries and
    merely stores the clients sending repeats so that when the
    first query completes, the answer can be sent to all the
    clients who asked. Refer: CVE-2020-25686.
    For more information, see:
    (* Security fix *)
  • news/2021/02/09/slackware-14.0-changelog.txt
  • Last modified: 15 months ago
  • by Giuseppe Di Terlizzi