Privilege escalation in VMware PKS and vCloud Director Container Service Extension

1) Privilege escalation

EUVDB-ID: #VU17474

Risk: Medium

CVSSv3.1: 7.6 [CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2019-5736

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to gain elevated privileges.

The weakness exists in the runc container runtime due to file-descriptor mishandling, related to /proc/self/exe. A remote attacker can leverage the ability to execute a command as root within one of these types of containers: (1) a new container with an attacker-controlled image, or (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec, overwrite the host runc binary with minimal user interaction and execute arbitrary code with root privileges.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation

Update VMware PKS to version 1.2.9 or 1.3.2. Update vCloud Director Container Service Extension to version 1.2.7.

Vulnerable software versions

vCloud Director Container Service Extension: 1.0.0 - 1.2.6

VMware PKS: 1.2.0 - 1.3.1

External links

http://www.vmware.com/security/advisories/VMSA-2019-0001.html

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.