#VU28180 NULL pointer dereference in Linux kernel


Published: 2020-05-22

Vulnerability identifier: #VU28180

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-10711

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the Linux kernel's SELinux subsystem when importing the Commercial IP Security Option (CIPSO) protocol's category bitmap into the SELinux extensible bitmap via the' ebitmap_netlbl_import' routine. While processing the CIPSO restricted bitmap tag in the 'cipso_v4_parsetag_rbm' routine, it sets the security attribute to indicate that the category bitmap is present, even if it has not been allocated.

A remote attacker can send specially crafted packets the affected system, trigger a NULL pointer dereference error and crash the Linux kernel.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 4.18 - 4.18.20, 3.10 - 3.10.107, 2.6 - 2.6_test9_cvs, 5.0 - 5.0.21


External links
http://www.openwall.com/lists/oss-security/2020/05/12/2
http://access.redhat.com/security/cve/cve-2020-10711
http://bugzilla.redhat.com/show_bug.cgi?id=1825116
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4b8feff251da3d7058b5779e21b33a85c686b974


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.


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