`head -cNUM ... | tr -dc SET` might generate output containing fewer
than NUM characters. Given the limited alphabet, this could result in a
fairly weak passphrase. The construction `tr </dev/urandom | head
-cNUM`, however, is sure to give us the full `NUM`.
From LWN:
From the NVD entries:
CVE-2016-5501: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect confidentiality,
integrity, and availability via vectors related to Core, a different
vulnerability than CVE-2016-5538.
CVE-2016-5538: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect confidentiality,
integrity, and availability via vectors related to Core, a different
vulnerability than CVE-2016-5501.
CVE-2016-5605: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.1.4 in Oracle Virtualization allows remote
attackers to affect confidentiality and integrity via vectors related
to VRDE.
CVE-2016-5608: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect availability via vectors
related to Core, a different vulnerability than CVE-2016-5613.
CVE-2016-5610: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect confidentiality,
integrity, and availability via vectors related to Core.
CVE-2016-5611: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect confidentiality via
vectors related to Core.
CVE-2016-5613: Unspecified vulnerability in the Oracle VM VirtualBox
component before 5.0.28 and 5.1.x before 5.1.8 in Oracle
Virtualization allows local users to affect availability via vectors
related to Core, a different vulnerability than CVE-2016-5608.