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             AUSCERT External Security Bulletin Redistribution

               [SECURITY] [DLA 1884-1] linux security update
                              14 August 2019


        AusCERT Security Bulletin Summary

Product:           linux
Publisher:         Debian
Operating System:  Debian GNU/Linux 8
Impact/Access:     Root Compromise        -- Existing Account
                   Access Privileged Data -- Existing Account
                   Denial of Service      -- Existing Account
                   Reduced Security       -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-14284 CVE-2019-14283 CVE-2019-13631
                   CVE-2019-10638 CVE-2019-10207 CVE-2019-3900
                   CVE-2019-1428 CVE-2019-1125 CVE-2018-20836

Reference:         ASB-2019.0229

Original Bulletin: 

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Package        : linux
Version        : 3.16.72-1
CVE ID         : CVE-2017-18509 CVE-2018-20836 CVE-2019-1125 CVE-2019-3900
                 CVE-2019-10207 CVE-2019-10638 CVE-2019-13631 CVE-2019-14283

Several vulnerabilities have been discovered in the Linux kernel that
may lead to a privilege escalation, denial of service or information


    Denis Andzakovic reported a missing type check in the IPv4 multicast
    routing implementation. A user with the CAP_NET_ADMIN capability (in
    any user namespace) could use this for denial-of-service (memory
    corruption or crash) or possibly for privilege escalation.


    chenxiang reported a race condition in libsas, the kernel
    subsystem supporting Serial Attached SCSI (SAS) devices, which
    could lead to a use-after-free.  It is not clear how this might be


    It was discovered that most x86 processors could speculatively
    skip a conditional SWAPGS instruction used when entering the
    kernel from user mode, and/or could speculatively execute it when
    it should be skipped.  This is a subtype of Spectre variant 1,
    which could allow local users to obtain sensitive information from
    the kernel or other processes.  It has been mitigated by using
    memory barriers to limit speculative execution.  Systems using an
    i386 kernel are not affected as the kernel does not use SWAPGS.


    It was discovered that vhost drivers did not properly control the
    amount of work done to service requests from guest VMs.  A
    malicious guest could use this to cause a denial-of-service
    (unbounded CPU usage) on the host.


    The syzkaller tool found a potential null dereference in various
    drivers for UART-attached Bluetooth adapters.  A local user with
    access to a pty device or other suitable tty device could use this
    for denial-of-service (BUG/oops).


    Amit Klein and Benny Pinkas discovered that the generation of IP
    packet IDs used a weak hash function, "jhash".  This could enable
    tracking individual computers as they communicate with different
    remote servers and from different networks.  The "siphash"
    function is now used instead.


    It was discovered that the gtco driver for USB input tablets could
    overrun a stack buffer with constant data while parsing the device's
    descriptor.  A physically present user with a specially
    constructed USB device could use this to cause a denial-of-service
    (BUG/oops), or possibly for privilege escalation.


    The syzkaller tool found a missing bounds check in the floppy disk
    driver.  A local user with access to a floppy disk device, with a
    disk present, could use this to read kernel memory beyond the
    I/O buffer, possibly obtaining sensitive information.


    The syzkaller tool found a potential division-by-zero in the
    floppy disk driver.  A local user with access to a floppy disk
    device could use this for denial-of-service (oops).

(CVE ID not yet assigned)

    Denis Andzakovic reported a possible use-after-free in the
    TCP sockets implementation.  A local user could use this for
    denial-of-service (memory corruption or crash) or possibly
    for privilege escalation.

(CVE ID not yet assigned)

    The netfilter conntrack subsystem used kernel addresses as
    user-visible IDs, which could make it easier to exploit other
    security vulnerabilities.


    Julien Grall reported that Linux does not limit the amount of memory
    which a domain will attempt to balloon out, nor limits the amount of
    "foreign / grant map" memory which any individual guest can consume,
    leading to denial of service conditions (for host or guests).

For Debian 8 "Jessie", these problems have been fixed in version

We recommend that you upgrade your linux packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS

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