A recently discovered vulnerability in the ISE Posture (System Scan) module of Cisco Secure Client for Linux could potentially allow an attacker, with local access and authentication, to elevate their privileges on an affected device. This vulnerability has been identified and assigned the CVE identifier CVE-2024-20338. In this blog post, we will delve into the details of this vulnerability, including code snippets, links to the original references, and exploitation details.

Vulnerability Details

The vulnerability in the ISE Posture (System Scan) module of Cisco Secure Client for Linux is caused by the use of an uncontrolled search path element. Specifically, when the ISE Posture module is initiated, the software performs a search for specific library files in a predetermined set of locations. However, an attacker could exploit this vulnerability by copying a malicious library file to a certain directory in the filesystem and persuading an administrator to restart the affected process.

Here is a step-by-step overview of how an attacker can potentially exploit this vulnerability

1. Create a malicious library file – The attacker creates a malicious library file with the same name as the legitimate library file, and embeds arbitrary code inside the malicious library file.

#include <stdio.h>
#include <stdlib .h>

void _init() {

2. Copy the malicious library file to the uncontrolled search path – The attacker copies the malicious library file to a specific directory in the filesystem, such as /tmp or another location that is writable by the attacker. This causes the affected process to unknowingly load the malicious library when it is restarted.

$ cp malicious_library.so /tmp

3. Persuade the administrator to restart the affected process – The attacker persuades an administrator to restart the affected process, either through social engineering tactics or by manipulating the system in a way that necessitates restarting the process.

4. Execute arbitrary code with root privileges – Once the process is restarted, the malicious library file is loaded instead of the legitimate library file, leading to the execution of the arbitrary code embedded within it. Consequently, the attacker can gain root privileges on the affected device.


At the time of writing this blog post, there has been no patch or software update released by Cisco to fix this vulnerability. However, administrators can keep themselves updated by regularly checking Cisco's Security Advisories for any updates on this issue.

In the meantime, administrators can take certain precautions to minimize the risk of this vulnerability. They can restrict write access to directories specified in the search path, monitor the filesystem for any potential unauthorized access or file modifications, and educate users on the potential risks of unknowingly executing malicious code.


The CVE-2024-20338 vulnerability poses a significant security risk for devices running Cisco Secure Client for Linux, as it could potentially allow an attacker to escalate their privileges and execute arbitrary code with root privileges. It is crucial for administrators to be aware of this vulnerability, take appropriate precautions, and stay informed on any updates or patches released by Cisco. Awareness and preparedness are the best defenses against potential security threats.


Published on: 03/06/2024 17:15:09 UTC
Last modified on: 03/07/2024 13:52:27 UTC