VMware has released an updated security advisory and additional software updates to address the VMware VMX process RPC command arbitrary code execution vulnerability.
Multiple VMware products contain a vulnerability that could allow an authenticated, local attacker to execute arbitrary code or cause a denial of service (DoS) on a targeted system.
The vulnerability is due to improper handling of certain remote procedure call (RPC) commands by the affected software. A authenticated, local attacker could exploit this vulnerability by sending crafted RPC commands to the system. If successful, the attacker could execute arbitrary code or cause a DoS condition on the system.
Proof-of-concept exploit code is publicly available.
VMware has confirmed this vulnerability and released updated software.
The following VMware products are vulnerable:
VMware ESX versions 3.5, 4.0 and 4.1
VMware ESXi versions 3.5, 4.0 and 4.1
VMware Workstation versions prior to 7.1.5
VMware Player versions prior to 3.1.6
To exploit this vulnerability, the attacker would need to send crafted RPC commands to the targeted system. Depending on the network configuration, the attacker would need access to trusted, internal networks and to be authenticated to the virtual machine. These access requirements decreases the likelihood of a successful exploit.
VMware recommends several workarounds. Administrators may configure VMs to use less than 4 gigabytes (GB) of memory. VMs that use less than 4GB are not vulnerable.
Administrators may also refer to the workaround described in VMware Knowledge Base article 1714; disable VIX (VIX API) messages from guest VMs by updating the guest .vmx configuration file and adding the following line:
isolation.tools.vixMessage.disable = TRUE
(This workaround is not applicable to VMware Workstation 7.x)
VMware has released an updated security advisory at the following link: VMSA-2012-0009
An authenticated, local attacker could exploit this vulnerability to execute arbitrary code on a targeted system. The attacker could also exploit this vulnerability to cause a DoS condition on the system.
The vulnerability is in the handler function used by the affected software for RPC commands.
An authenticated, local attacker could exploit this vulnerability by sending crafted RPC commands to a targeted system. Processing the commands could allow the attacker to manipulate data pointers in the VMX process and overwrite system memory. If successful, the attacker could execute arbitrary code on the system or cause a DoS condition.
Administrators are advised to apply the appropriate updates.
Administrators may consider configuring VMs to use less than 4 GB of memory.
Administrators may consider disabling VIX messages from guest VMs.
Administrators are advised to allow only trusted users to access local systems.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
VMware has released updated software at the following links:
Version 3, May 17, 2012, 3:05PM: Proof-of-concept code that exploits the VMware ESX and ESXi VMX process RPC command arbitrary code execution vulnerability is publicly available.
Version 2, May 7, 2012, 12:35PM: VMware ESX and ESXi contain a vulnerability that could allow an authenticated, local attacker to execute arbitrary code or cause a denial of service on a targeted system. Updates are available.
Version 1, May 4, 2012, 6:10PM: VMware ESX and ESXi contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system. Updates are available.
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