Xen DEBUGCTL MSR Denial of Service Vulnerability [CVE-2018-15468]

CVE Number – CVE-2018-15468

A vulnerability in Xen could allow a local attacker on a guest system to cause a denial of service (DoS) condition.

The vulnerability is due to improper value checks by the affected software. An attacker on a guest system could exploit this vulnerability by enabling the Branch Trace Store (BTS) feature of DEBUGCTL MSR. A successful exploit could cause the targeted host system to stop responding, resulting in a DoS condition.

Xen.org has confirmed the vulnerability and released software updates.

Analysis
  • To exploit this vulnerability, the attacker must have user-level access to a guest system on a targeted host system. This access requirement could reduce the likelihood of a successful exploit.

    Only systems using Intel CPUs are affected and only x86 HVM or PVH guests can exploit the vulnerability. x86 PV guests cannot exploit the vulnerability.

Safeguards
  • Administrators are advised to apply the appropriate updates.

    Administrators are advised to allow only trusted users to access local systems.

    Administrators are advised to allow only privileged users to access administration or management systems.

    Administrators are advised to monitor critical systems.

Vendor Announcements
  • Xen.org has released a security advisory at the following link: XSA-269

Fixed Software




Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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