CVE-2021-34788 : Security Advisory and Response

A vulnerability in the shared library loading mechanism of Cisco AnyConnect Secure Mobility Client for Linux and Mac OS could allow an authenticated, local attacker to perform a shared library hijacking attack on an affected device if the VPN Posture (HostScan) Module is installed on the AnyConnect client. This vulnerability is due to a race condition in the signature verification process for shared library files that are loaded on an affected device. An attacker could exploit this vulnerability by sending a series of crafted interprocess communication (IPC) messages to the AnyConnect process. A successful exploit could allow the attacker to execute arbitrary code on the affected device with root privileges. To exploit this vulnerability, the attacker must have a valid account on the system.

Understanding CVE-2021-34788

This section provides detailed information about the impact, technical details, and mitigation strategies related to CVE-2021-34788.

What is CVE-2021-34788?

The vulnerability in Cisco AnyConnect Secure Mobility Client for Linux and Mac OS allows a local attacker to execute arbitrary code with root privileges by exploiting a race condition in the shared library loading mechanism.

The Impact of CVE-2021-34788

The vulnerability poses a high risk as it could lead to an attacker gaining full control over the affected device, compromising confidentiality, integrity, and availability.

Technical Details of CVE-2021-34788

This section discusses the vulnerability description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

A race condition in the shared library loading process of Cisco AnyConnect Secure Mobility Client for Linux and Mac OS can be exploited by a local attacker to achieve arbitrary code execution with root privileges.

Affected Systems and Versions

The vulnerability affects Cisco AnyConnect Secure Mobility Client for Linux and Mac OS with the VPN Posture (HostScan) Module installed.

Exploitation Mechanism

An attacker can exploit this vulnerability by sending crafted interprocess communication (IPC) messages to the AnyConnect process, allowing them to execute arbitrary code with root privileges.

Mitigation and Prevention

To address CVE-2021-34788, immediate steps, long-term security practices, and patching guidelines are crucial.

Immediate Steps to Take

Organizations should disable or remove the VPN Posture (HostScan) Module to mitigate the risk until a patch is available. Additionally, restricting access to the affected systems is advised.

Long-Term Security Practices

Regularly updating the Cisco AnyConnect Secure Mobility Client and implementing security best practices can enhance the overall security posture.

Patching and Updates

Cisco may release a security patch to address the vulnerability. Organizations are recommended to apply the patch as soon as it is available to mitigate the risk of exploitation.