kdeconnect -- packet manipulation can be exploited in a Denial of Service attack

Albert Astals Cid reports:

KDE Project Security Advisory

Title
KDE Connect: packet manipulation can be exploited in a Denial of Service attack

Risk Rating
Important

CVE
CVE-2020-26164

Versions
kdeconnect <= 20.08.1

Author
Albert Vaca Cintora <[email protected]>

Date
2 October 2020

Overview

      An attacker on your local network could send maliciously crafted
      packets to other hosts running kdeconnect on the network, causing
      them to use large amounts of CPU, memory or network connections,
      which could be used in a Denial of Service attack within the
      network.

Impact

      Computers that run kdeconnect are susceptible to DoS attacks from
      the local network.

Workaround

      We advise you to stop KDE Connect when on untrusted networks like
      those on airports or conferences.
    

      Since kdeconnect is dbus activated it is relatively hard to make
      sure it stays stopped so the brute force approach is to uninstall
      the kdeconnect package from your system and then run
    

      kquitapp5 kdeconnectd
  

    Just install the package again once you're back in a trusted
    network.

Solution

    KDE Connect 20.08.2 patches several code paths that could result
    in a DoS.

You can apply these patches on top of 20.08.1:

      https://invent.kde.org/network/kdeconnect-kde/-/commit/f183b5447bad47655c21af87214579f03bf3a163
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/b279c52101d3f7cc30a26086d58de0b5f1c547fa
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/d35b88c1b25fe13715f9170f18674d476ca9acdc
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/b496e66899e5bc9547b6537a7f44ab44dd0aaf38
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/5310eae85dbdf92fba30375238a2481f2e34943e
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/721ba9faafb79aac73973410ee1dd3624ded97a5
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/ae58b9dec49c809b85b5404cee17946116f8a706
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/66c768aa9e7fba30b119c8b801efd49ed1270b0a
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/85b691e40f525e22ca5cc4ebe79c361d71d7dc05
    

      https://invent.kde.org/network/kdeconnect-kde/-/commit/48180b46552d40729a36b7431e97bbe2b5379306

Credits

    Thanks Matthias Gerstner and the openSUSE security team for
    reporting the issue.
  

    Thanks to Aleix Pol, Nicolas Fella and Albert Vaca Cintora for the
    patches.