Virtuozzo 6 : parallels-server-bm-release / vzkernel / etc (VZA-2017-025)

This script is Copyright (C) 2017 Tenable Network Security, Inc.


Synopsis :

The remote Virtuozzo host is missing multiple security updates.

Description :

According to the versions of the parallels-server-bm-release /
vzkernel / etc packages installed, the Virtuozzo installation on the
remote host is affected by the following vulnerabilities :

- A flaw was found in the Linux kernel's handling of
packets with the URG flag. Applications using the
splice() and tcp_splice_read() functionality can allow
a remote attacker to force the kernel to enter a
condition in which it can loop indefinitely.

- It was discovered that a remote attacker could leverage
the generation of IPv6 atomic fragments to trigger the
use of fragmentation in an arbitrary IPv6 flow (in
scenarios in which actual fragmentation of packets is
not needed) and could subsequently perform any type of
a fragmentation-based attack against legacy IPv6 nodes
that do not implement RFC6946.

- It was found that the blk_rq_map_user_iov() function in
the Linux kernel's block device implementation did not
properly restrict the type of iterator, which could
allow a local attacker to read or write to arbitrary
kernel memory locations or cause a denial of service
(use-after-free) by leveraging write access to a
/dev/sg device.

- A flaw was found in the Linux kernel's implementation
of the SCTP protocol. A remote attacker could trigger
an out-of-bounds read with an offset of up to 64kB
potentially causing the system to crash.

- A flaw was found in the Linux networking subsystem
where a local attacker with CAP_NET_ADMIN capabilities
could cause an out-of-bounds memory access by creating
a smaller-than-expected ICMP header and sending to its
destination via sendto().

- It was found that when file permissions were modified
via chmod and the user modifying them was not in the
owning group or capable of CAP_FSETID, the setgid bit
would be cleared. Setting a POSIX ACL via setxattr sets
the file permissions as well as the new ACL, but
doesn't clear the setgid bit in a similar way. This
could allow a local user to gain group privileges via
certain setgid applications.

- It was found that when the gcc stack protector was
enabled, reading the /proc/keys file could cause a
panic in the Linux kernel due to stack corruption. This
happened because an incorrect buffer size was used to
hold a 64-bit timeout value rendered as weeks.

- A race condition flaw was found in the ioctl_send_fib()
function in the Linux kernel's aacraid implementation.
A local attacker could use this flaw to cause a denial
of service (out-of-bounds access or system crash) by
changing a certain size value.

- When creating audit records for parameters to executed
children processes, an attacker can convince the Linux
kernel audit subsystem can create corrupt records which
may allow an attacker to misrepresent or evade logging
of executing commands.

- A flaw was discovered in the way the Linux kernel dealt
with paging structures. When the kernel invalidated a
paging structure that was not in use locally, it could,
in principle, race against another CPU that is
switching to a process that uses the paging structure
in question. A local user could use a thread running
with a stale cached virtual->physical translation to
potentially escalate their privileges if the
translation in question were writable and the physical
page got reused for something critical (for example, a
page table).

- A flaw was found in the USB-MIDI Linux kernel driver: a
double-free error could be triggered for the 'umidi'
object. An attacker with physical access to the system
could use this flaw to escalate their privileges.

Note that Tenable Network Security has extracted the preceding
description block directly from the Virtuozzo security advisory.
Tenable has attempted to automatically clean and format it as much as
possible without introducing additional issues.

See also :

https://help.virtuozzo.com/customer/portal/articles/2777857
https://rhn.redhat.com/errata/RHSA-2016-2766.html
https://rhn.redhat.com/errata/RHSA-2017-0036.html
https://rhn.redhat.com/errata/RHSA-2017-0293.html
https://rhn.redhat.com/errata/RHSA-2017-0307.html
https://rhn.redhat.com/errata/RHSA-2017-0817.html

Solution :

Update the affected parallels-server-bm-release / vzkernel / etc packages.

Risk factor :

Critical / CVSS Base Score : 10.0
(CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 7.8
(CVSS2#E:POC/RL:OF/RC:C)
Public Exploit Available : true

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