ALAS-2018-1023

References: CVE-2017-13215  CVE-2017-16939  CVE-2018-1000199  CVE-2018-10675  CVE-2018-1068  CVE-2018-1087  CVE-2018-10901  CVE-2018-1091  CVE-2018-1108  CVE-2018-7995  CVE-2018-8897 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

A weakness was found in the Linux kernel's implementation of random seed data. Programs, early in the boot sequence, could use the data allocated for the seed before it was sufficiently generated. (CVE-2018-1108)

A flaw was found in the way the Linux kernel handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged system user could use this flaw to crash the system kernel resulting in the denial of service. (CVE-2018-8897)

A flaw was found in the Linux kernel's implementation of 32-bit syscall interface for bridging. This allowed a privileged user to arbitrarily write to a limited range of kernel memory. (CVE-2018-1068)

The Linux kernel is vulerable to a use-after-free flaw when Transformation User configuration interface(CONFIG_XFRM_USER) compile-time configuration were enabled. This vulnerability occurs while closing a xfrm netlink socket in xfrm_dump_policy_done. A user/process could abuse this flaw to potentially escalate their privileges on a system. (CVE-2017-16939)

A flaw was found in the Linux kernel where a crash can be triggered from unprivileged userspace during core dump on a POWER system with a certain configuration. This is due to a missing processor feature check and an erroneous use of transactional memory (TM) instructions in the core dump path leading to a denial of service.(CVE-2018-1091)

An address corruption flaw was discovered in the Linux kernel built with hardware breakpoint (CONFIG_HAVE_HW_BREAKPOINT) support. While modifying a h/w breakpoint via 'modify_user_hw_breakpoint' routine, an unprivileged user/process could use this flaw to crash the system kernel resulting in DoS OR to potentially escalate privileges on a the system.(CVE-2018-1000199)

A flaw was found in the way the Linux kernel's KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest or, potentially, escalate their privileges in the guest.(CVE-2018-1087)

A flaw was found in the Linux kernel's skcipher component, which affects the skcipher_recvmsg function. Attackers using a specific input can lead to a privilege escalation.(CVE-2017-13215)

The do_get_mempolicy() function in mm/mempolicy.c in the Linux kernel allows local users to hit a use-after-free bug via crafted system calls and thus cause a denial of service (DoS) or possibly have unspecified other impact. Due to the nature of the flaw, privilege escalation cannot be fully ruled out.(CVE-2018-10675)

A flaw was found in Linux kernel's KVM virtualization subsystem. The VMX code does not restore the GDT.LIMIT to the previous host value, but instead sets it to 64KB. With a corrupted GDT limit a host's userspace code has an ability to place malicious entries in the GDT, particularly to the per-cpu variables. An attacker can use this to escalate their privileges.(CVE-2018-10901)

A race condition in the store_int_with_restart() function in arch/x86/kernel/cpu/mcheck/mce.c in the Linux kernel allows local users to cause a denial of service (panic) by leveraging root access to write to the check_interval file in a /sys/devices/system/machinecheck/machinecheck<cpu number> directory. (CVE-2018-7995)

Issue Correction:
Run yum update kernel then reboot the instance to update your system.

New Packages:

i686:
    kernel-4.14.42-52.37.amzn1.i686
    kernel-debuginfo-common-i686-4.14.42-52.37.amzn1.i686
    kernel-headers-4.14.42-52.37.amzn1.i686
    perf-debuginfo-4.14.42-52.37.amzn1.i686
    kernel-tools-4.14.42-52.37.amzn1.i686
    perf-4.14.42-52.37.amzn1.i686
    kernel-tools-debuginfo-4.14.42-52.37.amzn1.i686
    kernel-debuginfo-4.14.42-52.37.amzn1.i686
    kernel-devel-4.14.42-52.37.amzn1.i686
    kernel-tools-devel-4.14.42-52.37.amzn1.i686

src:
    kernel-4.14.42-52.37.amzn1.src

x86_64:
    kernel-tools-4.14.42-52.37.amzn1.x86_64
    kernel-debuginfo-common-x86_64-4.14.42-52.37.amzn1.x86_64
    kernel-4.14.42-52.37.amzn1.x86_64
    kernel-tools-debuginfo-4.14.42-52.37.amzn1.x86_64
    kernel-tools-devel-4.14.42-52.37.amzn1.x86_64
    kernel-debuginfo-4.14.42-52.37.amzn1.x86_64
    kernel-devel-4.14.42-52.37.amzn1.x86_64
    perf-4.14.42-52.37.amzn1.x86_64
    perf-debuginfo-4.14.42-52.37.amzn1.x86_64
    kernel-headers-4.14.42-52.37.amzn1.x86_64