Pierluigi Paganini April 10, 2020

VMware has addressed a critical information disclosure vulnerability related to the Directory Service that can be exploited to compromise vCenter Server.

VMware has addressed a critical information disclosure flaw, tracked as CVE-2020-3952, that could be exploited by attackers to compromise vCenter Server or other services that use the Directory Service (vmdir) for authentication.

The CVE-2020-3952 vulnerability has received a CVSSv3 score of 10, it resides in the vCenter Server version 6.7 on Windows and virtual appliances.

According to VMware, the vulnerability could be exploited only on vCenter Server installs that ware upgraded from a previous version.  Clean installs of vCenter Server 6.7 (embedded or external PSC) are not impacted.

The vulnerability has been addressed with the release of the 6.7u3f update.

“A sensitive information disclosure vulnerability in the VMware Directory Service (vmdir) was privately reported to VMware. vCenter updates are available to address this vulnerability.” reads the advisory published by WMware. “Under certain conditions¹ vmdir that ships with VMware vCenter Server, as part of an embedded or external Platform Services Controller (PSC), does not correctly implement access controls. VMware has evaluated the severity of this issue to be in the Critical severity range with a maximum CVSSv3 base score of 10.0.”

VMware users can determine if they are affected by searching for vmdir entries in the logs because a log entry is created when the vmdir service starts stating that legacy ACL mode is enabled.

Below an example provided by WMware:

2020-04-06T17:50:41.860526+00:00 info vmdird  t@139910871058176: ACL MODE: Legacy

In March, VMware has released security updates to address high severity privilege escalation and denial-of-service (DoS) flaws in the Workstation, Fusion, Remote Console and Horizon Client.

The two security vulnerabilities have been tracked as CVE-2020-3950 and CVE-2020-3951 respectively.

The CVE-2020-3950 is a privilege escalation vulnerability caused by the improper use of setuid binaries, it could be exploited by attackers to escalate privileges to root.

The CVE-2020-3951 vulnerability is a denial-of-service issue caused by a heap-overflow issue in Cortado Thinprint.

Pierluigi Paganini

(SecurityAffairs – Virtualization, hacking)

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