Enhancing Cisco IOS XE Security: Safeguarding Against BADCANDY Threats

Cisco IOS XE Vulnerability Exploited by Cybercriminals,’BADCANDY’ Implant Deployed

November 1,2025 – Cybercriminals are currently leveraging a security flaw within Cisco IOS XE software to deploy a malicious implant known as “BADCANDY,” posing a important threat to network infrastructure globally.

The Threat: BADCANDY Implant

Since October 2023,with renewed activity observed throughout 2024 and 2025,attackers have been successfully installing variants of the BADCANDY implant on vulnerable Cisco IOS XE devices. This Lua-based web shell is relatively unsophisticated, but offers attackers a foothold within compromised systems. Attackers are often attempting to conceal their activities by applying temporary fixes to mask the underlying vulnerability.

How Does BADCANDY Operate?

The BADCANDY implant itself doesn’t maintain persistence after a device is restarted. However, if malicious actors have already obtained login credentials or implemented other methods of maintaining access, thay can continue to exploit the compromised system or network even after a reboot. It’s critical to address the root cause of the vulnerability, which lies in CVE-2023-20198.

CVE-2023-20198: A Critical Weakness

CVE-2023-20198 impacts the web user interface (UI) of Cisco IOS XE software. Prosperous exploitation allows unauthenticated attackers to remotely create a high-privilege account, effectively granting them control of the vulnerable system. This vulnerability was notably exploited by the threat actor known as SALT TYPHOON,and was among the most frequently targeted weaknesses in 2023.

Global Impact and Response

The Australian Signals Directorate (ASD) estimates that over 400 devices in Australia were potentially compromised with BADCANDY as of July 2025, with more than 150 still affected at the end of October 2025. The ASD believes a variety of actors, including both criminal organizations and state-sponsored groups, might potentially be utilizing the implant.

The ASD proactively notified affected organizations thru their service providers, providing instructions on patching systems, restarting devices, and implementing security hardening measures. These notifications will continue on an ongoing basis to alert operators to potential compromises.

Key Recommendations for Organizations

The following measures are recommended to remove existing BADCANDY implants and prevent future exploitation:

• Examine the running configuration for user accounts with permission level 15 and eliminate any unfamiliar or unauthorized accounts.
• Pay close attention to accounts with random character strings,or accounts named “cisco_tac_admin,” “cisco_support,” “cisco_sys_manager,” or “cisco,” deleting those that aren’t legitimate.
• Inspect the running configuration for unknown tunnel interfaces.
• If TACACS+ is enabled, review AAA command logging for any unauthorized configuration changes.

Patching is Paramount

Organizations using the Cisco IOS XE Web UI are strongly urged to promptly install the available patch and follow the recommendations outlined in Cisco’s security advisories regarding “Multiple vulnerabilities in the Web UI feature of Cisco IOS XE software.” Cisco has issued active exploitation notices and provided indicators of compromise to help identify suspicious activity.

Restarting Devices: A Temporary Fix

While restarting a device will remove the BADCANDY implant, it does not address the root vulnerability. A restart is only a temporary measure. Organizations must subsequently scrutinize the current configuration for any unusual or unauthorized changes.

Did you know? The BADCANDY implant’s initial discovery dates back to October 2023, but its activity continues to be a significant concern for network security professionals.

Vulnerability	Impact	Mitigation
CVE-2023-20198	Remote code execution via web UI	Apply Cisco patch, restrict web UI access
BADCANDY Implant	Compromised system control	Remove malicious accounts, monitor for tunnel interfaces

Staying Ahead of Network Threats

The exploitation of Cisco IOS XE highlights the importance of proactive vulnerability management and robust network security practices. Regularly patching systems and restricting access to sensitive interfaces are crucial steps in mitigating risk. It’s also essential to monitor network traffic for malicious activity and implement strong authentication measures.

pro Tip: Consider implementing network segmentation to limit the blast radius of a potential breach.this can definitely help contain an attack and prevent it from spreading throughout your entire network.

Frequently Asked Questions

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What are the specific IOS XE versions impacted by the BADCANDY vulnerability (CVE-2023-20190)?

Understanding the BADCANDY Vulnerability

The BADCANDY vulnerability (CVE-2023-20190) represents a meaningful threat to network infrastructure relying on Cisco IOS XE software. This critical vulnerability allows an unauthenticated, remote attacker to gain control of affected systems. The root cause lies in a weakness within the WebUI component of IOS XE, specifically related to handling crafted HTTP resource requests. Exploitation can lead to arbitrary code execution, complete system compromise, and potential data breaches. Understanding the specifics of this Cisco IOS XE vulnerability is the first step towards effective mitigation. Key terms related to this include IOS XE security, network security, and remote code execution.

identifying Affected Systems & Versions

Determining if your network devices are vulnerable is paramount. The BADCANDY vulnerability impacts a wide range of Cisco IOS XE versions. Here’s a breakdown:

* affected Software: Cisco IOS XE Software (versions 17.6.6a and earlier,17.9.4a and earlier, 17.10.1a and earlier)

* Specific Devices: Catalyst 9000 series switches, Cisco Industrial Routers, and other platforms running the vulnerable IOS XE versions.

* Verification: Utilize the Cisco Software Checker tool (https://software.cisco.com/softwarechecker/) to quickly identify impacted devices within your environment. Regular vulnerability scanning is crucial.

Immediate Mitigation Steps: Emergency Response

Following the initial discovery of BADCANDY, cisco released urgent recommendations. These should be considered your immediate response:

1. Disable HTTP Server: the most effective short-term mitigation is to disable the HTTP server on affected devices. This prevents attackers from exploiting the WebUI vulnerability. Use the command no ip http server in global configuration mode.
2. Disable WebUI: If disabling the HTTP server isn’t feasible, disable the WebUI specifically using no platform webui.
3. Restrict Access: Implement strict access control lists (ACLs) to limit access to the HTTP and HTTPS interfaces to only authorized personnel. This is a core network access control practice.
4. Monitor for Suspicious Activity: Closely monitor network traffic for any unusual patterns or indicators of compromise (IOCs). Utilize intrusion detection systems (IDS) and intrusion prevention systems (IPS).

Long-Term Security Hardening: Proactive Measures

Beyond emergency responses, a robust security posture requires proactive hardening.

1. Software Updates & Patch Management

* Prioritize Updates: Apply the security patches released by Cisco as soon as possible. Cisco provides detailed upgrade guides for each affected platform.

* Automated Patching: Implement an automated patch management system to streamline the update process and ensure timely application of security fixes.

* Testing: Thoroughly test updates in a lab environment before deploying them to production networks.

2. Access Control & Authentication

* Strong Passwords: Enforce strong password policies for all user accounts.

* Multi-Factor Authentication (MFA): Implement MFA wherever possible, especially for administrative access.

* Role-Based Access Control (RBAC): Grant users only the privileges necessary to perform their duties. minimize administrative access.

* privileged Access Management (PAM): Implement a PAM solution to control and monitor access to privileged accounts.

3.Network Segmentation

* divide and Conquer: Segment your network into smaller, isolated zones. This limits the blast radius of a potential breach.

* Firewalling: Utilize firewalls to control traffic flow between network segments.

* Microsegmentation: Consider microsegmentation for even greater granularity and control.

4. Logging and monitoring

* Centralized Logging: Centralize logs from all network devices for extensive analysis.

* Security Information and Event Management (SIEM): Deploy a SIEM solution to correlate events,detect anomalies,and generate alerts.

* netflow/sFlow: Utilize NetFlow or sFlow to monitor network traffic patterns.

Real-World Implications & Case Studies

While specific details of successful BADCANDY exploits are frequently enough kept confidential, the potential impact is clear. Several organizations reported suspicious activity following the public disclosure of the vulnerability. One publicly reported incident involved a managed service provider (MSP) whose clients’ networks were potentially compromised due to unpatched IOS XE devices. This highlights the importance of proactive vulnerability management, especially for organizations that manage infrastructure for others. The incident underscored the need for rapid incident response planning.

Benefits of a Proactive Security Approach

Investing in robust Cisco IOS XE security measures yields significant benefits:

* Reduced Risk: Minimizes the likelihood of successful attacks and data breaches.

* Improved Compliance: Helps meet regulatory requirements and industry standards.

* Enhanced Reputation: Protects your association’s reputation and customer trust.

* Business Continuity: Ensures the availability and reliability of critical network services.

* **Cost