=========================================================================Ubuntu Security Notice USN-2684-1
July 23, 2015

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

- Ubuntu 15.04

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

A flaw was discovered in the kvm (kernel virtual machine) subsystem's
kvm_apic_has_events function. A unprivileged local user could exploit this
flaw to cause a denial of service (system crash). (CVE-2015-4692)

Daniel Borkmann reported a kernel crash in the Linux kernel's BPF filter
JIT optimization. A local attacker could exploit this flaw to cause a
denial of service (system crash). (CVE-2015-4700)

A flaw was discovered in how the Linux kernel handles invalid UDP
checksums. A remote attacker could exploit this flaw to cause a denial of
service using a flood of UDP packets with invalid checksums.
(CVE-2015-5364)

A flaw was discovered in how the Linux kernel handles invalid UDP
checksums. A remote attacker can cause a denial of service against
applications that use epoll by injecting a single packet with an invalid
checksum. (CVE-2015-5366)

Update instructions:

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

Ubuntu 15.04:
  linux-image-3.19.0-23-generic   3.19.0-23.24
  linux-image-3.19.0-23-generic-lpae  3.19.0-23.24
  linux-image-3.19.0-23-lowlatency  3.19.0-23.24
  linux-image-3.19.0-23-powerpc-e500mc  3.19.0-23.24
  linux-image-3.19.0-23-powerpc-smp  3.19.0-23.24
  linux-image-3.19.0-23-powerpc64-emb  3.19.0-23.24
  linux-image-3.19.0-23-powerpc64-smp  3.19.0-23.24

After a standard system update you need to reboot your computer to make
all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed. If
you use linux-restricted-modules, you have to update that package as
well to get modules which work with the new kernel version. Unless you
manually uninstalled the standard kernel metapackages (e.g. linux-generic,
linux-server, linux-powerpc), a standard system upgrade will automatically
perform this as well.

References:
  https://ubuntu.com/security/notices/USN-2684-1
  CVE-2015-4692, CVE-2015-4700, CVE-2015-5364, CVE-2015-5366

Package Information:
  https://launchpad.net/ubuntu/+source/linux/3.19.0-23.24