Table of Contents
February 6, 2025
|6m
How to Protect Cisco ISE from CVE-2025-20124: Critical Remote Command Execution Vulnerability?
Cisco Identity Services Engine (ISE) is a critical component for network access control. Recently, a severe vulnerability, CVE-2025-20124, has been identified in Cisco ISE, posing a significant threat to network security. This vulnerability could allow a remote attacker to execute arbitrary commands with root privileges on affected devices.
This article dives into the specifics of CVE-2025-20124, providing security professionals with the necessary information to understand the risks, determine if their systems are vulnerable, and implement effective mitigation strategies. This includes security professionals who work in DevSecOps, application security, product security, vulnerability management and assessment, penetration testing and red teams, and security operations and engineering teams. Our goal is to provide actionable guidance to protect your Cisco ISE deployments from potential exploitation.
A Short Introduction to Cisco ISE
Cisco Identity Services Engine (ISE) is a network administration product that enables enterprises to enforce security policies and ensure compliance across their networks. It provides centralized access control, guest access management, profiling, posture assessment, and threat mitigation capabilities. ISE integrates with various network devices and security solutions to provide a comprehensive approach to network security.
Summary of CVE-2025-20124
Here's a quick rundown of the vulnerability:
CVE ID: CVE-2025-20124
Description: A vulnerability in an API of Cisco ISE could allow an authenticated, remote attacker to execute arbitrary commands as the root user on an affected device.
CVSS Score: 9.9 (Critical)
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H
CVE-2025-20124 stems from insecure deserialization of user-supplied Java byte streams within a specific API of Cisco ISE. An attacker with valid read-only administrative credentials can exploit this vulnerability by sending a crafted serialized Java object to the affected API. Successful exploitation would allow the attacker to execute arbitrary commands on the device with root privileges. In a single-node deployment, new devices will not be able to authenticate during the reload time.
Impact of CVE-2025-20124
The impact of CVE-2025-20124 is significant due to the potential for remote command execution with root privileges. A successful exploit could allow an attacker to:
Gain complete control of the affected Cisco ISE device.
Compromise network access control policies.
Exfiltrate sensitive data.
Disrupt network operations.
Elevate privileges within the network.
The vulnerability has a CVSS v3.1 base score of 9.9, indicating a critical severity level. The impact on confidentiality is low, while the impact on integrity and availability is high. The scope is changed, meaning the vulnerable component impacts resources beyond its security scope. Due to the criticality of ISE in network security, a successful exploit could have far-reaching consequences. You can find more information about CVSS at thesecmaster.com.
Products Affected by CVE-2025-20124
The vulnerability affects Cisco ISE and Cisco ISE Passive Identity Connector (ISE-PIC), regardless of device configuration. It is crucial to identify the versions of ISE deployed in your environment to assess potential exposure. For further details, refer to the Cisco Security Advisory.
|
Product
|
Vulnerable Versions
|
Fixed Version(s)
|
|---|---|---|
|
Cisco ISE
|
3.0, 3.1, 3.2, 3.3
|
3.1P10, 3.2P7, 3.3P4, 3.4 (Not vulnerable)
|
|
Cisco ISE Passive Identity Connector (ISE-PIC)
|
3.0, 3.1, 3.2, 3.3
|
3.1P10, 3.2P7, 3.3P4, 3.4 (Not vulnerable)
|
Products Confirmed Not Vulnerable:
Cisco ISE Software Release 3.4
How to Check Your Product is Vulnerable?
To determine if your Cisco ISE deployment is vulnerable to CVE-2025-20124, consider the following checks:
Software Version: Log in to the Cisco ISE administration console and check the software version. Compare the version against the "Vulnerable Versions" column in the table above.
Feature Check: While the vulnerability affects all configurations, verify if the NX-API feature is enabled and if there are any suspicious configurations.
Network Monitoring: Monitor network traffic for suspicious activity, especially HTTP POST requests containing serialized Java objects directed towards the ISE API endpoints. For those new to the topic, here's what is security information and event management.
Authentication Logs: Examine the authentication logs for any unusual patterns, such as successful logins from unexpected sources or failed login attempts followed by successful ones.
How to Fix the Vulnerabilities?
Cisco has released software updates to address CVE-2025-20124. It is highly recommended to upgrade to a fixed software release as soon as possible. You can also check NVD CVE details.
Primary Remediation Strategy: Upgrade to a Fixed Software Release
Refer to the "Fixed Version(s)" column in the table above to identify the appropriate target release for your current version of Cisco ISE. Follow the documented upgrade procedures provided by Cisco for your specific ISE deployment. For instructions on upgrading a device, see the Upgrade Guides located on the Cisco Identity Service Engine support page.
Workarounds
Cisco has stated that there are no workarounds that address these vulnerabilities.
Additional Security Measures (If patching is not immediately possible)
While patching is the primary solution, consider these additional measures to mitigate the risk if immediate patching is not feasible:
Restrict Access to the API: Implement network access controls to limit access to the affected ISE API to only authorized users and systems.
Monitor for Suspicious Activities: Continuously monitor network traffic and system logs for any suspicious activities, particularly those involving Java serialization. Analyzing logs effectively may require tools like Splunk platform.
Implement Strong Authentication: Enforce strong password policies and consider implementing multi-factor authentication (MFA) for administrative access to Cisco ISE.
Disable Unnecessary APIs: If the vulnerable API is not critical for your operations, consider temporarily disabling it until a patch can be applied.
Stay Informed: Monitor official Cisco security channels for any updates or new information regarding this vulnerability.
Intrusion Detection/Prevention Systems (IDS/IPS): Deploy or update IDS/IPS rules to detect and block attempts to exploit this vulnerability.
By following these steps, you can significantly reduce the risk of exploitation and protect your Cisco ISE deployments from CVE-2025-20124. Remember, proactive patching and continuous monitoring are essential for maintaining a strong security posture.
Found this article interesting? Keep visit thesecmaster.com, and our social media page on Facebook, LinkedIn, Twitter, Telegram, Tumblr, Medium, and Instagram and subscribe to receive tips like this.
You may also like these articles:
Arun KL
Arun KL is a cybersecurity professional with 15+ years of experience in IT infrastructure, cloud security, vulnerability management, Penetration Testing, security operations, and incident response. He is adept at designing and implementing robust security solutions to safeguard systems and data. Arun holds multiple industry certifications including CCNA, CCNA Security, RHCE, CEH, and AWS Security.
