Linux Kernel - Multiple Vulnerabilities

Background

The Linux kernel is the core component of the Linux operating system. It provides essential services and functions for the proper functioning of the system. The kernel manages system resources, handles hardware interactions, and enables communication between software and hardware components. Due to its critical role, vulnerabilities in the Linux kernel can have severe consequences for system security and stability.

Vulnerability Detail

Multiple vulnerabilities have been discovered in the Linux kernel. These vulnerabilities include privilege escalation, denial of service, information leaks, and potential execution of arbitrary code. Some of the notable vulnerabilities include:

• CVE-2017-7482: A flaw in RxRPC Kerberos 5 ticket handling code could lead to information disclosure, denial of service, or arbitrary code execution.
• CVE-2017-7542: An integer overflow vulnerability in the ip6_find_1stfragopt() function could allow a local attacker to cause a denial of service.
• CVE-2017-7889: The mm subsystem does not properly enforce the CONFIG_STRICT_DEVMEM protection mechanism, allowing a local attacker to obtain sensitive information or execute arbitrary code.
• CVE-2017-10661: The timerfd facility does not handle certain concurrent operations correctly, leading to denial of service or potential arbitrary code execution.
• CVE-2017-10911: An information leak flaw in Xen blkif response handling could allow a malicious unprivileged guest to obtain sensitive information from the host or other guests.
• CVE-2017-11176: The mq_notify() function does not set the sock pointer to NULL, allowing an attacker to cause denial of service or other impact.
• CVE-2017-11600: The xfrm subsystem does not properly validate a parameter, allowing local users to cause denial of service or execute arbitrary code.
• CVE-2017-12134: Linux running in a Xen PV domain on an x86 system may incorrectly merge block I/O requests, leading to denial of service or potential arbitrary code execution.
• CVE-2017-12153: The cfg80211 (wifi) subsystem does not properly validate parameters, allowing local users with CAP_NET_ADMIN capability to cause denial of service.
• CVE-2017-12154: The KVM implementation for Intel x86 processors does not handle certain nested hypervisor configurations correctly, leading to denial of service.
• CVE-2017-14106: A specific sequence of operations on a TCP socket could lead to division by zero, resulting in denial of service.
• CVE-2017-14140: The move_pages() system call allows users to discover the memory layout of a set-UID process, making it easier to exploit vulnerabilities in set-UID programs.
• CVE-2017-14156: An information leak in the atyfb video driver allows local users to obtain sensitive information.
• CVE-2017-14340: The XFS implementation allows the creation of files with the realtime flag on a filesystem with no realtime device, leading to a crash.
• CVE-2017-14489: The iSCSI subsystem does not properly validate the length of a netlink message, leading to memory corruption and denial of service or arbitrary code execution.
• CVE-2017-1000111: A race condition in the raw packet (af_packet) feature allows local users with CAP_NET_RAW capability to cause denial of service or arbitrary code execution.
• CVE-2017-1000251: The Bluetooth subsystem does not properly validate L2CAP configuration responses, leading to a stack buffer overflow and denial of service or arbitrary code execution.
• CVE-2017-1000363: The lp driver does not properly bounds-check passed arguments, but this has no security impact in Debian.
• CVE-2017-1000365: Argument and environment pointers are not properly taken into account by the size restrictions on arguments and environmental strings passed through execve(), allowing local attackers to execute arbitrary code.
• CVE-2017-1000380: A race condition in the ALSA (sound) timer driver leads to an information leak, allowing local users to obtain sensitive information.

sudo apt-get install --only-upgrade linux

Workaround

For the vulnerability identified as CVE-2017-12134, a workaround is available to disable merges on the underlying block devices. This can be achieved by executing the following command:

echo 2 > /sys/block/nvme0n1/queue/nomerges

This workaround prevents the exploitation of the vulnerability and mitigates the associated risks.

Conclusion

The Linux kernel is prone to multiple vulnerabilities that can have severe consequences for system security and stability. It is crucial to promptly upgrade the kernel to the patched versions provided by the Linux distribution. Additionally, applying workarounds, such as disabling merges for the specific vulnerability identified as CVE-2017-12134, can further mitigate the risks. For further support on vulnerability remediation, please contact DevNack.com.

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