🚨Cisco IOS XE Arbitrary File Upload Vulnerability Exploited🚨

Critical Cisco IOS XE Arbitrary File Upload Vulnerability Exploited

A newly disclosed critical flaw in Cisco IOS XE, tracked as CVE-2025–20188, is raising alarms across the cybersecurity community. Technical details now made public demonstrate how attackers can exploit the bug to achieve remote code execution (RCE), placing enterprise wireless infrastructure at serious risk. Although a complete plug-and-play exploit is not yet available, the detailed analysis by researchers leaves very little to the imagination. This puts the burden on CISOs and security teams to act quickly before threat actors operationalize the exploit.

CVE-2025–20188: What Makes It So Dangerous?

On May 7, 2025, Cisco disclosed this maximum-severity vulnerability in its IOS XE Wireless LAN Controllers (WLC). The issue stems from a hardcoded JWT (JSON Web Token) secret that allows unauthenticated attackers to upload files, traverse file paths, and run arbitrary code with root-level access.

• The flaw is only exploitable if the Out-of-Band AP Image Download feature is enabled. Affected devices include:
• Catalyst 9800-CL Wireless Controllers for Cloud
• Catalyst 9800 Embedded Wireless Controller (for 9300, 9400, 9500 Switches)
• Catalyst 9800 Series Wireless Controllers
• Embedded Wireless Controller on Catalyst APs
• For CISOs, this is a textbook example of how default configurations and embedded secrets can create enterprise-scale exposure.

Anatomy of the Exploit

Security researchers at Horizon3 uncovered that Cisco’s backend logic falls back to using "notfound" as a JWT secret if the expected key file is absent. The backend, built with OpenResty (Lua + Nginx), trusts any token signed using this fallback string.

Here’s how the attack unfolds:

• Generate a JWT signed using HS256 and the string "notfound"
• Send a POST request with a malicious payload to /ap_spec_rec/upload/ on port 8443
• Use path traversal in the filename to drop files outside the intended directory
• Overwrite configuration files used by backend services like pvp.sh
• Trigger a reload and execute attacker-controlled commands
• This effectively allows the attacker to upload web shells, hijack configuration, or run unauthorized code all without credentials.

Urgent Actions for CISOs and Network Teams

With exploit details now public, time is critical. Cisco has released patched firmware (version 17.12.04 or later). If patching isn’t immediately possible, CISOs are advised to disable the Out-of-Band AP Image Download feature as a temporary workaround.

Additional recommendations include:

• Monitor for unusual activity on port 8443 and upload endpoints
• Audit JWT usage in custom middleware or proxies
• Apply network segmentation to isolate vulnerable controllers
• Use file integrity monitoring on critical directories
• CISOs must also include this threat in their executive risk dashboards and incident response runbooks.

Strategic Importance for the CISO Role

This incident underscores the importance of secure defaults and vulnerability lifecycle management. For CISOs, it is a direct reminder to enhance security policies, ensure rapid patch validation, and enforce zero-trust segmentation across all layers of network infrastructure.

From a leadership perspective, this flaw demands executive awareness, cross-team coordination, and swift action — hallmarks of a mature cyber resilience strategy.

Closing Thoughts

The publication of CVE-2025–20188’s exploitation path marks a shift from theoretical risk to imminent operational threat. Organizations relying on Cisco WLCs must move beyond detection to active defense, led by their CISOs and supported by partners experienced in real-world attack surface reduction.

Wire Tor: Your Frontline Cybersecurity Partner

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