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             AUSCERT External Security Bulletin Redistribution

                      USN-3917-1: snapd vulnerability
                               22 March 2019


        AusCERT Security Bulletin Summary

Product:           snapd
Publisher:         Ubuntu
Operating System:  Ubuntu
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-7303  

Original Bulletin: 

Comment: This advisory references vulnerabilities in products which run on 
         platforms other than Ubuntu. It is recommended that administrators 
         running snapd check for an updated version of the software for their
         operating system.

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USN-3917-1: snapd vulnerability

21 March 2019

snapd vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  o Ubuntu 18.10
  o Ubuntu 18.04 LTS
  o Ubuntu 16.04 LTS
  o Ubuntu 14.04 LTS


An intended access restriction in snapd could be bypassed by strict mode snaps
on 64 bit architectures.

Software Description

  o snapd - Daemon and tooling that enable snap packages


The snapd default seccomp filter for strict mode snaps blocks the use of the
ioctl() system call when used with TIOCSTI as the second argument to the system
call. Jann Horn discovered that this restriction could be circumvented on 64
bit architectures. A malicious snap could exploit this to bypass intended
access restrictions to insert characters into the terminal's input queue. On
Ubuntu, snapd typically will have already automatically refreshed itself to
snapd 2.37.4 which is unaffected.

Update instructions

The problem can be corrected by updating your system to the following package

Ubuntu 18.10
    snapd - 2.37.4+18.10.1
Ubuntu 18.04 LTS
    snapd - 2.37.4+18.04.1
Ubuntu 16.04 LTS
    snapd - 2.37.4ubuntu0.1
Ubuntu 14.04 LTS
    snapd - 2.37.4~14.04.1

To update your system, please follow these instructions: https://
wiki.ubuntu.com/Security/Upgrades .

In general, a standard system update will make all the necessary changes.


  o CVE-2019-7303
  o LP: 1812973

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