Virtuozzo 6 : parallels-server-bm-release / vzkernel / etc (VZA-2017-025)
Critical Nessus Plugin ID 99106
SynopsisThe remote Virtuozzo host is missing multiple security updates.
DescriptionAccording 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.
SolutionUpdate the affected parallels-server-bm-release / vzkernel / etc packages.