EulerOS 2.0 SP5 : kernel (EulerOS-SA-2019-1076)
Medium Nessus Plugin ID 122699
SynopsisThe remote EulerOS host is missing multiple security updates.
DescriptionAccording to the versions of the kernel packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :
- A security flaw was found in the ip_frag_reasm() function in net/ipv4/ip_fragment.c in the Linux kernel which can cause a later system crash in ip_do_fragment(). With certain non-default, but non-rare, configuration of a victim host, an attacker can trigger this crash remotely, thus leading to a remote denial of service.(CVE-2018-14641)
- A flaw named FragmentSmack was found in the way the Linux kernel handled reassembly of fragmented IPv4 and IPv6 packets. A remote attacker could use this flaw to trigger time and calculation expensive fragment reassembly algorithm by sending specially crafted packets which could lead to a CPU saturation and hence a denial of service on the system.(CVE-2018-5391)
- The resv_map_release function in mm/hugetlb.c in the Linux kernel, through 4.15.7, allows local users to cause a denial of service (BUG) via a crafted application that makes mmap system calls and has a large pgoff argument to the remap_file_pages system call. (CVE-2018-7740)
- A use-after-free vulnerability was found in the way the Linux kernel's KVM hypervisor emulates a preemption timer for L2 guests when nested (=1) virtualization is enabled. This high resolution timer(hrtimer) runs when a L2 guest is active. After VM exit, the sync_vmcs12() timer object is stopped. The use-after-free occurs if the timer object is freed before calling sync_vmcs12() routine. A guest user/process could use this flaw to crash the host kernel resulting in a denial of service or, potentially, gain privileged access to a system.
- An information leakage issue was found in the way Linux kernel's KVM hypervisor handled page fault exceptions while emulating instructions like VMXON, VMCLEAR, VMPTRLD, and VMWRITE with memory address as an operand.
It occurs if the operand is a mmio address, as the returned exception object holds uninitialized stack memory contents. A guest user/process could use this flaw to leak host's stack memory contents to a guest.
- The xfs_dinode_verify function in fs/xfs/libxfs/xfs_inode_buf.c in the Linux kernel can cause a NULL pointer dereference in xfs_ilock_attr_map_shared function. An attacker could trick a legitimate user or a privileged attacker could exploit this by mounting a crafted xfs filesystem image to cause a kernel panic and thus a denial of service.
- The Linux kernel is vulnerable to a NULL pointer dereference in the ext4/mballoc.c:ext4_process_freed_data() function. An attacker could trick a legitimate user or a privileged attacker could exploit this by mounting a crafted ext4 image to cause a kernel panic.(CVE-2018-1092)
- The Linux kernel is vulnerable to a NULL pointer dereference in the ext4/xattr.c:ext4_xattr_inode_hash() function. An attacker could trick a legitimate user or a privileged attacker could exploit this to cause a NULL pointer dereference with a crafted ext4 image.
- An issue was discovered in the XFS filesystem in fs/xfs/libxfs/xfs_attr_leaf.c in the Linux kernel. A NULL pointer dereference may occur for a corrupted xfs image after xfs_da_shrink_inode() is called with a NULL bp. This can lead to a system crash and a denial of service. (CVE-2018-13094)
- A flaw was found in the Linux kernel with files on tmpfs and hugetlbfs. An attacker is able to bypass file permissions on filesystems mounted with tmpfs/hugetlbs to modify a file and possibly disrupt normal system behavior. At this time there is an understanding there is no crash or privilege escalation but the impact of modifications on these filesystems of files in production systems may have adverse affects.
- A use-after-free flaw can occur in the Linux kernel due to a race condition between packet_do_bind() and packet_notifier() functions called for an AF_PACKET socket. An unprivileged, local user could use this flaw to induce kernel memory corruption on the system, leading to an unresponsive system or to a crash. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. (CVE-2018-18559)
- A flaw was found In the Linux kernel, through version 4.19.6, where a local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c.
An attacker could corrupt memory and possibly escalate privileges if the attacker is able to have physical access to the system.(CVE-2018-19824)
- An issue was discovered in the Linux kernel before 4.18.11. The ipddp_ioctl function in drivers/net/appletalk/ipddp.c allows local users to obtain sensitive kernel address information by leveraging CAP_NET_ADMIN to read the ipddp_route dev and next fields via an SIOCFINDIPDDPRT ioctl call.
- A use-after-free vulnerability was found in the way the Linux kernel's KVM hypervisor implements its device control API. While creating a device via kvm_ioctl_create_device(), the device holds a reference to a VM object, later this reference is transferred to the caller's file descriptor table. If such file descriptor was to be closed, reference count to the VM object could become zero, potentially leading to a use-after-free issue. A user/process could use this flaw to crash the guest VM resulting in a denial of service issue or, potentially, gain privileged access to a system. (CVE-2019-6974)
- Since Linux kernel version 3.2, the mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused.(CVE-2018-18281)
- A division-by-zero in set_termios(), when debugging is enabled, was found in the Linux kernel. When the [io_ti] driver is loaded, a local unprivileged attacker can request incorrect high transfer speed in the change_port_settings() in the drivers/usb/serial/io_ti.c so that the divisor value becomes zero and causes a system crash resulting in a denial of service. (CVE-2017-18360)
Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected kernel packages.