ID CVE-2020-10759
Summary A PGP signature bypass flaw was found in fwupd (all versions), which could lead to the installation of unsigned firmware. As per upstream, a signature bypass is theoretically possible, but not practical because the Linux Vendor Firmware Service (LVFS) is either not implemented or enabled in versions of fwupd shipped with Red Hat Enterprise Linux 7 and 8. The highest threat from this vulnerability is to confidentiality and integrity.
Vulnerable Configurations
  • cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
Base: 3.3 (as of 22-09-2020 - 16:51)
  • Padding Oracle Crypto Attack
    An adversary is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an adversary is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an adversary is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key. Any cryptosystem can be vulnerable to padding oracle attacks if the encrypted messages are not authenticated to ensure their validity prior to decryption, and then the information about padding error is leaked to the adversary. This attack technique may be used, for instance, to break CAPTCHA systems or decrypt/modify state information stored in client side objects (e.g., hidden fields or cookies). This attack technique is a side-channel attack on the cryptosystem that uses a data leak from an improperly implemented decryption routine to completely subvert the cryptosystem. The one bit of information that tells the adversary whether a padding error during decryption has occurred, in whatever form it comes, is sufficient for the adversary to break the cryptosystem. That bit of information can come in a form of an explicit error message about a padding error, a returned blank page, or even the server taking longer to respond (a timing attack). This attack can be launched cross domain where an adversary is able to use cross-domain information leaks to get the bits of information from the padding oracle from a target system / service with which the victim is communicating. To do so an adversary sends a request containing ciphertext to the target system. Due to the browser's same origin policy, the adversary is not able to see the response directly, but can use cross-domain information leak techniques to still get the information needed (i.e., information on whether or not a padding error has occurred). For instance, this can be done using "img" tag plus the onerror()/onload() events. The adversary's JavaScript can make web browsers to load an image on the target site, and know if the image is loaded or not. This is 1-bit information needed for the padding oracle attack to work: if the image is loaded, then it is valid padding, otherwise it is not.
cvss-vector via4 AV:L/AC:M/Au:N/C:P/I:P/A:N
redhat via4
id 1845714
title Show Details not working for e.g. Firefox installed from rpm
  • comment Red Hat Enterprise Linux must be installed
    oval oval:com.redhat.rhba:tst:20070304026
  • AND
    • comment Red Hat Enterprise Linux 8 is installed
      oval oval:com.redhat.rhba:tst:20193384074
    • OR
      • AND
        • comment libxmlb is earlier than 0:0.1.15-1.el8
          oval oval:com.redhat.rhsa:tst:20204436001
        • comment libxmlb is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20204436002
      • AND
        • comment libxmlb-debugsource is earlier than 0:0.1.15-1.el8
          oval oval:com.redhat.rhsa:tst:20204436003
        • comment libxmlb-debugsource is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20204436004
      • AND
        • comment gnome-software is earlier than 0:3.36.1-4.el8
          oval oval:com.redhat.rhsa:tst:20204436005
        • comment gnome-software is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20183140790
      • AND
        • comment gnome-software-debugsource is earlier than 0:3.36.1-4.el8
          oval oval:com.redhat.rhsa:tst:20204436007
        • comment gnome-software-debugsource is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20193553084
      • AND
        • comment appstream-data is earlier than 0:8-20200724.el8
          oval oval:com.redhat.rhsa:tst:20204436009
        • comment appstream-data is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20183140008
      • AND
        • comment fwupd is earlier than 0:1.4.2-4.el8
          oval oval:com.redhat.rhsa:tst:20204436011
        • comment fwupd is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20183140754
      • AND
        • comment fwupd-debugsource is earlier than 0:1.4.2-4.el8
          oval oval:com.redhat.rhsa:tst:20204436013
        • comment fwupd-debugsource is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20203216012
id RHSA-2020:4436
released 2020-11-04
severity Low
title RHSA-2020:4436: gnome-software and fwupd security, bug fix, and enhancement update (Low)
  • appstream-data-0:8-20200724.el8
  • fwupd-0:1.4.2-4.el8
  • fwupd-debuginfo-0:1.4.2-4.el8
  • fwupd-debugsource-0:1.4.2-4.el8
  • gnome-software-0:3.36.1-4.el8
  • gnome-software-debuginfo-0:3.36.1-4.el8
  • gnome-software-debugsource-0:3.36.1-4.el8
  • libxmlb-0:0.1.15-1.el8
  • libxmlb-debuginfo-0:0.1.15-1.el8
  • libxmlb-debugsource-0:0.1.15-1.el8
  • libxmlb-tests-debuginfo-0:0.1.15-1.el8
refmap via4
Last major update 22-09-2020 - 16:51
Published 15-09-2020 - 19:15
Last modified 22-09-2020 - 16:51
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