Privilege escalation in Linux kernel

1) Missing Authorization

EUVDB-ID: #VU56242

Risk: Low

CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-27777

CWE-ID: CWE-862 - Missing Authorization

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to the way RTAS handles memory accesses in userspace to kernel communication. On a locked down (usually due to Secure Boot) guest system running on top of PowerVM or KVM hypervisors (pseries platform) a root like user could use this flaw to further increase their privileges to that of a running kernel.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: All versions

External links

http://bugzilla.redhat.com/show_bug.cgi?id=1900844
http://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=bd59380c5ba4147dcbaad3e582b55ccfd120b764
http://www.openwall.com/lists/oss-security/2020/10/09/1
http://www.openwall.com/lists/oss-security/2020/11/23/2

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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