#VU78673 Permissions, Privileges, and Access Controls in linux-image-6.2.0-1006-ibm (Ubuntu package) - CVE-2023-2640

Vulnerability identifier: #VU78673

Vulnerability risk: Low

CVSSv4.0: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Clear]

CVE-ID: CVE-2023-2640

CWE-ID: CWE-264

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
linux-image-6.2.0-1006-ibm (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor: Canonical Ltd.

Description

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

The vulnerability exists due to missing permission checks for trusted.overlayfs.* xattrs". A local user can set privileged extended attributes on the mounted files, leading them to be set on the upper files without the appropriate security checks.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

linux-image-6.2.0-1006-ibm (Ubuntu package): before 6.2.0-1006.6

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External links
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640
https://ubuntu.com/security/notices/USN-6250-1
https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html
https://wiz.io/blog/ubuntu-overlayfs-vulnerability
https://www.zerodayinitiative.com/advisories/ZDI-23-1009/

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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. However, a fully functional exploit for this vulnerability is available.