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CVE-2017-18017: Linux Kernel: Use after free
CVE-2017-18017 is rated critical with a CVSS v3.1 base score of 9.8 and affects Linux Kernel, along with 28 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.
Vulnerability description
The tcpmss_mangle_packet function in net/netfilter/xt_TCPMSS.c in the Linux kernel before 4.11, and 4.9.x before 4.9.36, allows remote attackers to cause a denial of service (use-after-free and memory corruption) or possibly have unspecified other impact by leveraging the presence of xt_TCPMSS in an iptables action.
Severity breakdown
CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Unchanged. Impact stays within the vulnerable component.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-416: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
Affected products
- Linux Kernel: from 3.2 before 3.2.99; from 3.3 before 3.10.108; from 3.11 before 3.16.54; from 3.17 before 3.18.60; from 3.19 before 4.1.43; from 4.2 before 4.4.76; from 4.5 before 4.9.36; from 4.10 before 4.11
- Debian Linux: 7.0; 8.0
- Arista Eos: 4.20.1fx-virtual-router
- F5 Arx: from 6.2.0 up to and including 6.4.0
- Suse Caas Platform: all versions listed by NVD
- Suse Linux Enterprise Debuginfo: 11 sp3; 11 sp4
- Suse Linux Enterprise Module For Public Cloud: 12
- Suse Linux Enterprise Point Of Sale: 11 sp3
- Suse Openstack Cloud: 6
- Opensuse Leap: 42.3
- Suse Linux Enterprise Desktop: 12 sp2; 12 sp3
- Suse Linux Enterprise High Availability: 12 sp2; 12 sp3
- Suse Linux Enterprise High Availability Extension: 11 sp4
- Suse Linux Enterprise Live Patching: 12; 12 sp3
- Suse Linux Enterprise Real Time Extension: 11 sp4; 12 sp2; 12 sp3
References
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2638fd0f92d4397884fd991d8f4925cb3f081901
- http://patchwork.ozlabs.org/patch/746618/
- https://github.com/torvalds/linux/commit/2638fd0f92d4397884fd991d8f4925cb3f081901
- https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.36
- https://www.arista.com/en/support/advisories-notices/security-advisories/4577-security-advisory-34
- http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00008.html
- http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00013.html
- http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00015.html
- http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00038.html
- http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00047.html
- http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00030.html
- http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00067.html
- http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00070.html
- http://lists.opensuse.org/opensuse-security-announce/2018-03/msg00072.html